2019 Microchip Technology Inc. DS40001922C-page 1
maXTouch® Adaptive Sensing Touchscreen
Technology
• Up to 14 X (transmit) lines and 24 Y (receive) lines
(see Section 4.1 “Permitted Configurations”)
• A maximum of 336 nodes can be allocated to the
touchscreen
• Touchscreen size 5.47 inches (16:9 aspect ratio),
assuming a sensor electrode pitch of 5 mm. Other
sizes may be possible with different electrode pitches
and appropriate sensor material
• Multiple touch support with up to 10 concurrent
touches tracked in real time
Touch Sensor Technology
• Discrete/out-cell support including glass and PET film-
based sensors
• On-cell/touch-on display support including TFT, IPS
and OLED
• Synchronization with display refresh timing capability
• Support for standard (for example, Diamond) and
proprietary sensor patterns (review of designs by
Microchip recommended)
Front Panel Material
• Works with PET or glass, including curved profiles
(configuration and stack-up to be approved by
Microchip)
• Glass 0.4 mm to 4.5 mm (dependent on screen size,
touch size, configuration and stack-up)
• Plastic 0.2 mm to 2.2 mm (dependent on screen size,
touch size, configuration and stack-up)
Touch Performance
• Moisture/Water Compensation
- No false touch with condensation or water drop up
to 22 mm di ameter
- One-finger tracking with condensation or water
drop up to 22 mm diameter
• Glove Support
- Multiple-finger glove touches up to 1.5 mm
thickness (subject to stack-up design)
- Single-finger glove touch up to 5 mm thickness
(subject to stack-up design)
• Mutual capacitance and self capacitance
measurements supported for robust touch detection
• Noise suppression technology to combat ambient,
charger noise, and power-line noise
- Up to 240 Vpp betw een 1 Hz and 1 kHz
sinusoidal waveform
- Up to 20 Vpp between 1 kHz and 1 MHz
sinusoidal waveform
• Radiated Noise
- Flexible and dynamic Tx burst frequency selection
- Controlled Tx burst frequency drift over process
and temperature range
• Scan Speed
- Up to 250Hz one finger reporting rate, subject to
configuration
- Initial touch latency <12 ms for first touch from
idle, subject to configuration
- Typical report rate for 10 touches 60 Hz (subject
to configuration)
- Configurable to allow for power and speed
optimization
On-chip Gestures
• Supports wake up/unlock gesture s , including symbol
recognition
Keys
• Up to 8 nodes can be allocated as mutual capacitance
sensor keys (subject to other configurations)
• Support for 3 Generic Keys in addition to the
touchscreen array (subject to other configurations)
• Adjacent Key Suppression (AKS) technology is
supported for false key touch prevention
Enhanced Algorithms
• Lens bending algorithms to remove display noise
• Touch suppression algorithms to remove unintentional
large touches, such as palm
• Palm Recovery Algorithm for quick restoration to
normal state
• Stylus Support
- Supports passive stylus with 2.5 m m contact
diameter, subject to configuration, stack up, and
sensor design
mXT336U 1.0
maXTouch 336-node Touchscreen Controller
MXT336U 1.0
DS40001922C-page 2 2019 Microchip Technology Inc.
Product Data Store Area
• Up to 60 bytes of user-defined data can be stored during production
Power Saving
• Programmable timeout for automatic transition from active to idle states
• Pipelined analog sensing detection and digital processing to optimize system power efficiency
Application Interfaces
•I
2C-compatible slave mode: Standard/Fast mode 400 kHz
• Interrup t to indi ca te wh e n a me ssa ge is ava i l abl e
• SPI Debug Interface to read the real-time raw data for tuning and debugging purposes
Power Supply
• Digital (Vdd) 3.3 V nominal
• Analog (AVdd) 3.3 V nominal
• Host interface I/O voltage (VddIO) 3.3 V nominal
• High voltage internal X line drive (XVdd) 6.6 V, with internal voltage pump
Package
• 56-pin XQFN 6 × 6 × 0.4 mm, 0.35 mm pitch
Environmental Conditions
• Operating temperature –40C to +85C
Design Services
• Review of device configuration, stack-up and sensor patterns
• Custom firmware versions can be considered, such as specific gestures or propri etary OEM host communication
protocols
• Contact your Microchip representative for more information
2019 Microchip Technology Inc. DS40001922C-page 3
MXT336U 1.0
CONNECTION AND CONFIGURATION INFORMATION
Pin Configuration – 56-pin XQFN
39
40
42
41
38
37
36
35
34
33
32
31
30
29
56 55 54 53
49
50
5152 43
44
48 47 46 45
1
2
3
4
5
6
7
8
9
10
11
12
13
14
17
1615
18
19 20 24
23
2221 25 26 27 28
GND
Top View
X0
X1
X13
X12
X11
X10
X9
X8
X7
X6
X5
X4
X3
X2
EXTCAP0
VDD
VDDCORE
VDDIO
TEST/DBG2_CLK
SDA
SCL
RESET
CHG/DBG2_FRAME
SYNC/DBG_DATA/DBG2_DATA0
SCAN_OUT/DBG_CLK/DBG2_DATA1
DS0/GKEYX0/DBG2_DATA2
GKEYY0/DBG_SS/DBG2_DATA3
GKEYY1/DBG2_DATA4
XVDD
Y23
Y22
Y21
Y20
Y19
Y18
Y17
Y16
Y15
Y14
Y13
Y12
EXTCAP1
GKEYY2/NOISE_IN/DBG2_DATA5
Y11
Y10
Y9
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
Y0
AVDD
MXT336U 1.0
DS40001922C-page 4 2019 Microchip Technology Inc.
TABLE 0-1: PIN LISTING – 56-PIN XQFN
Pin Name Type Supply Description If Unused...
1 X0 S XVdd X line connection Leave open
2 X1 S XVdd X line connection Leave open
3 X2 S XVdd X line connection Leave open
4 X3 S XVdd X line connection Leave open
5 X4 S XVdd X line connection Leave open
6 X5 S XVdd X line connection Leave open
7 X6 S XVdd X line connection Leave open
8 X7 S XVdd X line connection Leave open
9 X8 S XVdd X line connection Leave open
10 X9 S XVdd X line connection Leave open
11 X10 S XVdd X line connection Leave open
12 X11 S XVdd X line connection Leave open
13 X12 S XVdd X line connection Leave open
14 X13 S XVdd X line connection Leave open
15 XVDD P XVdd X line drive power –
16 EXTCAP1 P – Voltage doubler – connect to EXTCAP0 via capacitor –
17 Y12 S AVdd Y line connection Leave open
18 Y13 S AVdd Y line connection Leave open
19 Y14 S AVdd Y line connection Leave open
20 Y15 S AVdd Y line connection Leave open
21 Y16 S AVdd Y line connection Leave open
22 Y17 S AVdd Y line connection Leave open
23 Y18 S AVdd Y line connection Leave open
24 Y19 S AVdd Y line connection Leave open
25 Y20 S AVdd Y line connection Leave open
26 Y21 S AVdd Y line connection Leave open
27 Y22 S AVdd Y line connection Leave open
28 Y23 S AVdd Y line connection Leave open
29 EXTCAP0 P – Voltage doubler – connect to EXTCAP1 via capacitor –
30 VDD P – Digital power –
31 VDDCORE P – Digital core power –
32 VDDIO P – Digital IO interface power –
33 TEST –VddIO Reserved for factory use; pull up to VddIO Pull up to VddIO
DBG2_CLK O Secondary Debug Clock
34 SDA OD VddIO Serial Interface Data –
35 SCL OD VddIO Serial Interface clock –
36 RESET I VddIO Reset low. Connection to host system is
recommended Pull up to VddIO
37 CHG OD VddIO
State change interrupt
Note: Briefly set (~100 ms) as an input after power-up/
reset for diagnostic purposes Pull up to VddIO
DBG2_FRAME O Secondary Debug Frame
38 SYNC I VddIO External synchronization –DBG_DATA O Primary Debug Data
DBG2_DATA0 O Secondary Debug Data 0
39 SCAN_OUT O VddIO
Indicates touch scanning in progress. Polarity
configurable Leave open
DBG_CLK O Primary Debug Clock
DBG2_DATA1 O Secondary Debug Data 1
2019 Microchip Technology Inc. DS40001922C-page 5
MXT336U 1.0
40 DS0 S Vdd
Driven Shield; used as guard track between X/Y
signals and ground Leave open
GKEYX0 S Generic keys X line
DBG2_DATA2 O Secondary Debug Data 2
41 GKEYY0 S Vdd Generic keys Y line Leave openDBG_SS O Primary Debug SS line
DBG2_DATA3 O Secondary Debug Data 3
42 GKEYY1 S Vdd Generic keys Y line Leave open
DBG2_DATA4 O Secondary Debug Data 4
43 GKEYY2 S Vdd Generic keys Y line Leave openNOISE_IN I Noise present input
DBG2_DATA5 O Secondary Debug Data 5
44 Y11 S AVdd Y line connection Leave open
45 Y10 S AVdd Y line connection Leave open
46 Y9 S AVdd Y line connection Leave open
47 Y8 S AVdd Y line connection Leave open
48 Y7 S AVdd Y line connection Leave open
49 Y6 S AVdd Y line connection Leave open
50 Y5 S AVdd Y line connection Leave open
51 Y4 S AVdd Y line connection Leave open
52 Y3 S AVdd Y line connection Leave open
53 Y2 S AVdd Y line connection Leave open
54 Y1 S AVdd Y line connection Leave open
55 Y0 S AVdd Y line connection Leave open
56 AVDD P – Analog power –
Pad GND P – Exposed pad must be connected to GND –
Key:
I Input only O Output only I/O Input or output
OD Open drain output P Ground or power S Sense pin
TABLE 0-1: PIN LISTING – 56-PIN XQFN (CONTINUED)
Pin Name Type Supply Description If Unused...
MXT336U 1.0
DS40001922C-page 6 2019 Microchip Technology Inc.
TABLE OF CONTENTS
Connection and Configuration Information ........................................................................................................................... 3
Table of Contents .................................................................................................................................................................. 6
To Our Valued Customers .................................................................................................................................................... 7
1.0 Overview of mXT336U ............................................................................................................................................... 8
2.0 Schematics ................................................................................................................................................................. 9
3.0 Touchscreen Basics ................................................................................................................................................. 12
4.0 Sensor Layout .......................................................................................................................................................... 13
5.0 Power-up / Reset Requirements .............................................................................................................................. 17
6.0 Detailed Operation ................................................................................................................................................... 20
7.0 I2C Communications ................................................................................................................................................ 23
8.0 PCB Design Considerations ..................................................................................................................................... 29
9.0 Getting Started with mXT336U ................................................................................................................................. 33
10.0 Debugging and Tuning ............................................................................................................................................. 37
11.0 Specifications ........................................................................................................................................................... 38
12.0 Packaging Information ............................................................................................................................................... 48
Appendix A. Associated Documents .................................................................................................................................. 50
Appendix B. Revision History .............................................................................................................................................. 51
Product Identification System ............................................................................................................................................. 55
The Microchip Web Site ...................................................................................................................................................... 56
Customer Change Notification Service ............................................................................................................................... 56
Customer Support ............................................................................................................................................................... 56
2019 Microchip Technology Inc. DS40001922C-page 7
MXT336U 1.0
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued cu stomers with the best documentation possible to ensure successful use of
your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our
publications will be refined and enhanced as new volumes and updates are introd uced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications
Department via E-mail at docerrors@microchip.com. We welcome your feedback.
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To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner
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A of document DS30000000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommende d workarounds, may
exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The
errata will specify the revision of silicon and revision of document to which it ap plies.
To determine if an errata sheet exists for a particular device, please check with one of the followi ng:
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When contacting Microchip, please specify which device, revision of silicon and data sheet (include literature number)
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Register on our web site at http://www .microchip.com to receive the most current information on all of our products.
MXT336U 1.0
DS40001922C-page 8 2019 Microchip Technology Inc.
1.0 OVERVIEW OF MXT336U
The Microchip maXTouch family of touch controllers brings ind ustry-leading capacitive touch performance to customer
applications. The mXT336U features the latest generation of Microchip adaptive sensing technology that utilizes a
hybrid mutual and self capacitive sensing system in order to deliver unparalleled touch features and a robust user
experience.
•Patented capacitive sensing method – The mXT336U uses a unique charge-transfer acquisitio n engine to
implement Microchip’s patented capacitive sensing method. Coupled with a state-of-the-art CPU, the entire
touchscreen sensing solution can measure, classify and track a number of individual finger touches with a high
degree of accuracy in the shortest respon se time.
•Capacitive Touch Engine (CTE) – The mXT336U features an acquisition engine, which uses an optimal
measurement approach to ensure almost complete immunity from parasitic capacitance on the receiver input
lines. The engine includes sufficient dynamic range to cope with anticipated touchscreen self and mutual
capacitances, which allows great flexibility for use with the Microchip proprietary sensor pattern designs. One- and
two-layer ITO sensors are possible using glass or PET substrates.
•Touch detection – The mXT336U allows for both mutual and self capacitance measurements, with the self
capacitance measurements being used to augment the mutual capacitance measurements to produce reliable
touch information.
When self capacitance measurements are enabled, touch classification is achieved using both mutual and self
capacitance touch data. This has the advantage that both types of measurement systems can work together to
detect touches under a wide variety of circumstances.
The system may be configured for various types of default measurements:
- Mutual Capacitance Touch Default Idle – During idle mode, the device performs mutual capacitance touch
scans.
- Mutual Capacitance Touch Default Active – During active mode, when one or more touches are detected, the
device performs mutual capacitance touch scans.
Note that in both of the above cases, other scans (for example, self capacitance touch) may also be made
depending on configuratio n.
- Self Capacitance Touch Default Idle – During idle mode, the device performs se lf capacitance touch scans.
- Self Capacitance Touch Default Active – During active mode, when a single touch is detected, the device
performs self capacitance touch scans. If multiple touches are detected, th e de vi ce pe rfo rms mu tu al
capacitance touch scans to process the touches.
The system may be configured for different types of default measurements in idle and active modes.
Mutual capacitance touch dat a is used wherever possible to classify touches as this has greater granularity than self
capacitance measurements and provides positional information on touches. For this reason, multiple touches can
only be determined by mutual capacitance touch data. In Self Capacitance Touch Default mode, if the self
capacitance touch processing detects multiple touches, touchscreen processing is skipped until mutual capacitance
touch data is available.
Self cap acita nce measur ement s, on the ot her hand, allo w for the detection of single touches in extreme cases, such
as single thick glove touches, when touches can only be detected by self capacitance data and may be missed by
mutual capacitance touch detection.
•Display Noise Cancellation – A combination of analog circuitry, hardware noise processing, and firmware that
combats display noise without requiring additional listening channels or synchronization to display timing. This
enables the use of shieldless touch sensor stacks, including touch-on-lens.
•Noise filtering – Hardware noise processing in the capacitive touch engine provides enhanced autonomous
filtering and allows a broad range of noise profiles to be handled. The result is good performance in the presence
of charger and LCD noise.
•Processing power – The main CPU has two powerful microsequencer coprocessors under its control consuming
low power. This system all ows the signal acquisition, preprocessing, postprocessing and housekeeping to be
partitioned in an efficient and flexible way.
•Interpreting user intention – The Microchip hybrid mutual and self capacitance method provi des unambiguous
multitouch performance. Algorithms in the mXT336U provide optimized touchscreen position filtering for the
smooth tracking of touches, responding to a user's intended touches while preventing false touches triggered by
ambient noise, conductive material on the sensor surface, such as moisture, or unintentiona l touches from the
user’s resting palm or fingers.
2019 Microchip Technology Inc. DS40001922C-page 9
MXT336U 1.0
2.0 SCHEMATICS
2.1 Schematic XQFN 56 Pins
See Section 2.2 “Schematic Notes”
SYNC
X5
X6
X7
X8
X9
X10
X11
X12
X13
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
Y8
Y9
Y10
Y11
Y12
Y13
Y14
Y15
Y16
Y17
Y18
Y19
X0
X1
X2
X3
X4
GND
Y20
Y21
Y22
Y23
GKEYY0
GKEYY1
GKEYY2/NOISE_IN
SCAN_OUT
EXTCAP0
EXTCAP1
X0 1
X2 3
X3 4
X4 5
X5 6
X6 7
X7 8
X8 9
X9 10
X10 11
X11 12
X12 13
X13 14
Y14 19
Y15 20
Y16 21
Y17 22
Y18 23
Y19 24
Y20 25
Y21 26
Y22 27
Y23 28
Y0 55
X1 2
RESET
36
GKEYY2/NOISE_IN/DBG2_DATA5
43
GKEYY1/DBG2_DATA4
42
SCL
35
SYNC/DBG_DATA/DBG2_DATA0
38
SCAN_OUT/DBG_CLK/DBG2_DATA1
39
GKEYX0/DS0/DBG2_DATA2
40
TEST/DBG2_CLK
33
SDA
34
GKEYY0/DBG_SS/DBG2_DATA3
41
VDD 30
VDDIO 32
AVDD 56
GND
PAD
VDDCORE 31
XVDD 15
EXTCAP0
29
EXTCAP1
16
Y1 54
Y2 53
Y3 52
Y4 51
Y5 50
Y6 49
Y7 48
Y8 47
Y9 46
Y10 45
Y11 44
Y12 17
Y13 18
CHG/DBG2_FRAME
37
SCL
SDA
RESET
CHG
2.2nF
Cd
GND
10nF
Creset
See Notes
Rp
VDDIO
Rp 10k
GKEYX0/DS0
10k
See Notes
10k
DBG_SS
DBG_DATA
DBG_CLK
10k
See Notes
VDD
VDDIO
VDDAVDD
22nF
GND
GND
22nF
22nF
GND
GND
22nF
1uF
2.2uF
1uF
22nF
2.2uF
GND
mXT336U
NOTE: See “Connection and Configuration Information”
for informati on on I/O pin supply
MXT336U 1.0
DS40001922C-page 10 2019 Microchip Technology Inc.
2.2 Schematic Notes
2.2.1 POWER SUPPLY
The sense and I/O pins are supplied by the power rails on the device as listed in Table 0-1. This information is also
indicated in “Connection and Configuration Information”.
s
2.2.2 DECOUPLING CAPACITORS
All decoupling capacitors must be X7R or X5R an d placed less than 5 mm awa y from the balls for which they act as
bypass capacitors. Pins of the same type can share a capacitor provided no pin is more than 10 mm from the capacitor .
The schematics on the previous pages show th e optimum capacitors required. The parallel combination of capacitors
is recommended to give high and low frequency filtering, which is beneficial if the voltage regulators are likely to be some
distance from the device (for example, If an active tail design is used). Note that this requires that the voltage regulator
supplies for A Vdd, Vdd and VddIO are clean and noise free. It also assumes that the track length between the capacitors
and on-board power supplies is less than 50 mm.
The number of base capacitors can be reduced if the pinout configuration means that sharing a bypass capacitor is
possible (subject to the distance between the pins satisfying the conditions above and there being no routing difficulties).
2.2.3 PULL-UP RESISTORS
The pull-up resistors shown in the schematic are suggested typical values and may be modified to meet the
requirements of an individual customer design. This applies, in particular , to the I2C pull-up resistor s (see Section 2.2.6
“I2C Interface”).
2.2.4 INTERNAL VOLTAGE PUMP
The voltage pump requires one exte rnal capacitor:
• EXTCAP0 must be connected to EXTCAP1 via a capa citor (Cd)
Capacitor Cd should provide a capacitance of 2.2 nF.
2.2.5 VDDCORE
VddCore is internally generated from the Vdd power suppl y. To guarantee stability of the internal voltage regulator, an
external capacitor is required. The capacitor should have a value of 1 µF.
2.2.6 I2C INTERFACE
The schematic shows pull-up resistors on the SDA and SCL lines. The values of these resistors depends on the speed
of the I2C interface. See Section 11.9 “I2C Specification” for details. Note that if a VddIO supply at the low end of the
allowable range is used, the pull-up resistor values may need to be reduced.
2.2.7 MULTIPLE FUNCTION PINS
Some pins may have multiple functions. In this case, only one function can be chosen and the circuit should be designed
accordingly.
CAUTION! The device may be permanently damaged if any XVDD pin is shorted to ground or high current is
drawn from it.
Table 0-1. Power Supply for Sense and I/O Pins
Power Supply Pins
XVdd X drive lines
AVdd Y sense lines
VddIO RESET, SYNC, SDA, SCL, CHG, SCAN_OUT, DBG_CLK, DBG_DATA
Vdd NOISE_IN, GKEYYn, GKEYX0, DS0, DBG_SS
2019 Microchip Technology Inc. DS40001922C-page 11
MXT336U 1.0
2.2.8 PRIMARY DEBUG LINES
The DBG_CLK, DBG_DATA and DBG_SS Lines form the SPI Debug Interface. These pins should be routed to test
points on all designs, such that they can be connected to external hardware during system development. See also
Section 10.1 “SPI Debug Interface”.
Note that the debug lines may share pins with other functionality. Only one function for each pin can be chosen and the
circuit should be designed accordingly. Note that the pull-up resistor for DBG_SS in the schematics is optional and
should be present only if the line is used as DBG_SS.
The DBG_CLK, DBG_DATA and DBG_SS lines should not be connected to power or GND.
MXT336U 1.0
DS40001922C-page 12 2019 Microchip Technology Inc.
3.0 TOUCHSCREEN BASICS
3.1 Sensor Construction
A touchscreen is usually constructed from a number of transparent electrodes. These are typically on a glass or plastic
substrate. They can also be made using non-transparent electrodes, such as copper or carbon. Electrodes are constructed
from Indium T in Oxide (ITO) or met al mesh. Thicker electrodes yield lower levels of resistance (perhaps tens to hundreds of /
square) at the expense of reduced optical clarity. Lower levels of resistance are generally more compatible with capacitive
sensing. Thinner electrodes lead to higher levels of re sistance (perhaps hundreds to thousands of /square) w ith so me of
the best optical characteristics.
Interconnecting tracks can cause problems. The excessive RC time constants formed between the resistance of the track and
the capacitance of the electrode to ground can inhibit the capacitive sensing function. In such cases, the tracks should be
replaced by screen p rinted conductive i nks (non-transpa rent) out side the touch screen viewing are a.
3.2 Electrode Configuration
The specific electrode designs used in Microchip touchscreens are the subject of various patents and patent
applications. Further information is availabl e on request.
The device supports various configurations of electrodes as summarized in Section 4.0 “Sensor Layout”.
3.3 Scanning Sequence
All nodes are scanned in sequence by the de vi ce . There is a ful l parallelism in the scanning sequence to improve overa ll
response time. The nodes are scanned by measuring cap aciti ve changes at the intersectio ns formed b etween th e first X line
and all th e Y lines. Then the in tersections betw een the ne xt X line an d all the Y lines are scan ned, and so on, until all X and Y
combinations ha ve been measured.
The d evice can be configured in various ways. It is possible to disable some nodes so that they are not scanned at all. This
can be used to improve overall scanning time.
3.4 Touchscreen Sensitivity
3.4.1 ADJUSTMENT
Sensitivity of touchscreens can vary across the extents of the electrode pattern due to natural differences in the parasitic
capacitance of the interconnections, control chip, and so on. An important factor in the uniformity of sensitivity is the
electrode design itself. It is a natural consequence of a touchscreen pattern that the edges form a discontinuity and
hence tend to have a different sensitiv ity. The e lectrodes at the far e dges do not h ave a neighb oring ele ctrode on o ne
side and this affects the electric fie ld distribution in that region.
A sensitivity adjustment is available for the whole touchscreen. This adjustment is a basic algorithmic threshold that
defines when a node is considered to have eno ugh signal change to qualify as being in detect.
3.4.2 MECHANICAL STACKUP
The mechanical stackup refers to the arrangement of materi al layers that exist above and below a touchscreen. The
arrangement of the touchscreen in relation to other parts of the mechanical stackup has an effect on the overall
sensitivity of the screen. QMatrix technology has an excellent ability to operate in the presence of ground planes close
to the sensor. QMatrix sensitivity is attributed more to the interactio n of the electric fi elds between the transmitting (X)
and receiving (Y) electrodes th an to the surface ar ea of these electrodes. F or this reason, stray capacitance on the X
or Y electrodes does not strongly reduce sensitivity.
Front panel dielectric material has a direct beari ng on sensitivity. Plastic front panels are usually suitable up to about
1.2 mm, and glass up to about 2.5 mm (dependent upon the screen size and layout ). The thicker the front panel, the
lower the signal-to-noise ratio of the measured capacitive changes and hence the lower the resolution of the
touchscreen. In general, glass front panels are near optimal because they conduct electric fields almost twice as easily
as plastic panels.
NOTE Care should be taken using ultra-thin glass panels as retransmission effects can occur, which can
significantly degrade performance.
2019 Microchip Technology Inc. DS40001922C-page 13
MXT336U 1.0
4.0 SENSOR LAYOUT
The specific electrode designs used in Microchip touchscreens are the subject of various patents and patent
applications. Further information is availabl e on request.
The physical matrix can be confi gured to have one o r mo re touch o bje cts. These are conf igu red usin g the approp riate
touch objects (Multiple Touch Touchscreen and Key Array). It is n ot mandatory to have al l the allow able touch objects
present. The objects are disabled by default so only those that you wish to use need to be enabled.
The device supports various configurations of electrodes as summarized below:
• Touchscreen: 14 X × 24 Y maximum (subject to other configurations)
• Standard Keys: Up to 8 keys in an X/Y grid (Key Array), implemented using sta ndard sense lines
• Generic Keys: Up to 3 keys in an X/Y grid (Key Array), implemented using the Generic Key lines
Note that the 3 nodes provided by th e Generic Key lines are in addition to the maximu m 336 nodes permitted on the
device. Note also that the Key Array must contain either Generic Key lines or standard sense lines, but not both.
When designing the physical layout of the touch panel, the following rules must be obeyed:
• Each touch object should be a regular rectangular shape in terms of the lines it uses.
• A Touchscreen object cannot share an X or Y line with another touch object if self-capacitance measurements are
enabled.
• The Touchscreen must start at X0, Y0.
• For mutual capacitance touchscreens, the following applies:
- The number of X lines supported must be 3 or higher. If Dual X Drive is enabled for use in the Noise
Suppression T72 object, the minimum is 4 X lines
- The number of Y lines supported must be 3 or higher
• For self capacitance touchscreens, the follow ing applies:
- The number of X lines supported must be in the range 8 to 14
- The number of Y lines supported must be one of: 24, 23, 20, 16, 12 or 8
• It is recommended that a standard Key Array should occupy th e highest X and Y lines within the XY touchscreen
matrix.
4.1 Permitted Configurations
The permitted configurations are shown in Table 4-1 and Table 4-2.
TABLE 4-1: PERMITTED TOUCHSCREEN CONFIGURATIONS – MUTUAL CAPACITANCE
Number of
Y Lines Number of X Lines
1413121110987654321
24 YYYYYYYYYYYX
23 YYYYYYYYYYYX
22 YYYYYYYYYYYX
21 YYYYYYYYYYYX
20 YYYYYYYYYYYX
19 YYYYYYYYYYYX
18 YYYYYYYYYYYX
17 YYYYYYYYYYYX
16 YYYYYYYYYYYX
15 YYYYYYYYYYYX
14 YYYYYYYYYYYX
13 YYYYYYYYYYYX
12 YYYYYYYYYYYX
11 YYYYYYYYYYYX
10 YYYYYYYYYYYX
9YYYYYYYYYYYX
8YYYYYYYYYYYX
7YYYYYYYYYYYX
6YYYYYYYYYYYX
5YYYYYYYYYYYX
4YYYYYYYYYYYX
3YYYYYYYYYYYX
2
1
Key: Y Configuration supported
X Configuration supported, but only if dual X is not used
Configuration not supported
MXT336U 1.0
DS40001922C-page 14 2019 Microchip Technology Inc.
4.2 Screen Size
Table 4-3 lists some typical screen size and electrode pitch combinations to achieve vario us aspect rati os.
4.3 Standard Key Array
For optimal performance in terms of cycle time overhead, it is recommended that the number of X (drive) lines used for
the standard Key Array is kept to the minimum and designs sho uld favor using Y li nes where possi ble (observing any
restriction on the number of Y lines that can be used).
Figure 4-1 on page 15 shows an example layout for a Touchscreen with a Key Array of 1 X × 4 Y lines. Note that in this
case using 1 X × 4 Y lines for the Key Array would give better performance than using 4 X × 1 Y lines.
TABLE 4-2: PERMITTED TOUCHSCREEN CONFIGURATIONS – SELF CAPACITANCE
Number of
Y Lines X Lines
1413121110987654321
24 YYYYYYY
23 YYYYYYY
22
21
20 YYYYYYY
19
18
17
16 YYYYYYY
15
14
13
12 YYYYYYY
11
10
9
8YYYYYYY
7
6
5
4
3
2
1
Key: Y Configuration supported
Configuration not supported
TABLE 4-3: TYPICAL SCREEN SIZES
Aspect Ratio Matrix Size Node Count
Screen Diagonal (Inches)
4 mm Pitch 5 mm Pitch 6 mm Pitch
16:10 X = 14, Y = 23 322 4.24 5.3 6.36
16:9 X = 14, Y = 24 336 4.38 5.47 6.56
4:3 X = 14, Y = 19 266 3.72 4.65 5.58
2:1 X = 12, Y = 24 288 4.23 5.28 6.34
2019 Microchip Technology Inc. DS40001922C-page 15
MXT336U 1.0
If, however , the intention is to preserve a larger touchscreen size and maintain an optimal aspect ratio, then using equal
X and Y lines for the key array can be considered, as in Figure 4-2 on page 15.
FIGURE 4-1: EXAMPLE LAYOUT – OPTIMAL CYCLE TIME
FIGURE 4-2: EXAMPLE LAYOUT – OPTIMAL ASPECT RATIO
XY Matrix
(Standard Sense
Lines)
XY Matrix
(Standard Sense
Lines)
Y0 X0
X13 Y23
Y20
Y19
Multiple Touch
Touchscreen
(13 X × 20 Y)
Keys
1 X × 4 Y
X12
XY Matrix
(Standard Sense
Lines)
XY Matrix
(Standard Sense
Lines)
XY Matrix
(Standard Sense
Lines)
Y0 X0
X12 X13 Y23
Y22
Y21
Multiple Touch
Touchscreen
(12 X × 22 Y)
Keys
2 X × 2 Y
X11
XY Matrix
(Standard Sense
Lines)
MXT336U 1.0
DS40001922C-page 16 2019 Microchip Technology Inc.
4.4 Generic Key Array
The Generic Key lines can be used to form 3 mutual capacitance nodes that can be used to form a Key Array only.
Using the Generic Keys may add extra noise line measu rements, which will impact power consumption and timings. It
is therefore recommended that, where spare mutual capacitance sense lines are available, the sense lines are used to
form a standard Key Array in preference to using the Generic Key lines.
FIGURE 4-3: EXAMPLE LAYOUT – TOUCHSCREEN WITH GENERIC KEYS
XY atrix
(Standard Se
nse Lines)
XY Matrix
(Standard Sense Lines)
X0
Y0
GKEYX0
GKEYY0
GKEYY2
Multiple Touch
touchscreen
(13 X × 24 Y)
X13
Generic Key Array
1 X x 3 Y
Y23
2019 Microchip Technology Inc. DS40001922C-page 17
MXT336U 1.0
5.0 POWER-UP / RESET REQUIRE ME NTS
5.1 Power-on Reset
There is an internal Power-on Reset (POR ) in the device.
If an external reset is to be used th e device must b e held in R ESET (active low) while the digital (Vdd) analog (AVdd)
and I/O (VddIO) power supplies are powering up. The supplies must have reached their nominal values before the
RESET signal is deasserted (that is, goes high). This is shown in Figure 5-1. See Section 11.2 “Recommended
Operating Conditions” for nominal valu es for Vdd, VddIO, and AVdd.
FIGURE 5-1: POWER SEQUENCING ON THE MXT336U
After power-up, the device typically takes 35 ms before it is ready to start communications.
If the RESET line is released before the A Vdd supply has reached its nominal voltage (see Figure 5-2 on page 18), then
some additional operations need to be carried out by the host. There are two options open to the host controller:
• Start the part in deep sleep mode and then send the command sequence to set the cycle time to wake the part
and allow it to run normally. Note that in this case a calibration command is also needed.
• Send a RESET command.
Note: When using external at power-up,RESET
VddIO must not be enabled after Vdd
RESET
(VddIO)
VddIO
AVdd
> 90 ns
Vdd
MXT336U 1.0
DS40001922C-page 18 2019 Microchip Technology Inc.
FIGURE 5-2: POWER SEQUENCING ON THE MXT336U – LATE RISE ON AVDD
The RESET pin can be used to reset the device whenever necessary. The RESET pin must be asserted low for at least
90 ns to cause a reset. After releasing the RESET pin the device typically takes 38 ms before it is ready to start
communications. It is recommended to connect the RESET pin to a host control ler to allo w it to i nitiate a full hardware
reset without requiring a power-down.
Make sure that any lines connected to the device are below or equ al to Vdd during power-up. For e xample, if RESET
is supplied from a different power domain to the VDDIO pi n, make sure that it is held low when Vdd is off. If this is not
done, the RESET signal could parasitically couple power via the RESET pin into the Vdd supply.
Note that the voltage level on the RESET pin of the device must never exceed VddIO (digital supply voltage).
A software RESET command (using the Command Processor T6 object) can be used to reset the chip. A software reset
takes typically 55 ms. After the chip has finished it asserts the CHG line to signal to the host that a message is available.
The reset flag is set in the Message Processor object to indicate to the host that it has just completed a reset cycle. This
bit can be used by the host to detect any unexpected brownout events. This allows the host to take any necessary
corrective actions, such as reconfiguration.
A checksum check is performed on the configuration settings held in the nonvolatile memory. If the checksum does not
match a stored copy of the last checksum, then this indicates that the settings have become corrupted. This is signaled
to the host by setting the configuration error bit in the message data for the Command Processor T6 object.
Note that the CHG line is briefly set as an in put during power-up or reset. It is therefore particularly important that the
line should be allowed to float high via the CHG line pull-up resistor during this peri od. It should not be driven by the
host (see Table 11.6.3 on pag e 45).
At power-on, the device performs a self-test routine (using the Self Test T25 object) to check for shorts that might cause
damage to the device.
5.2 Power-up and Reset Sequence – VddIO Enabled after Vdd
The power-up sequence that can be used in applications where VddIO must be powered up after Vdd, is shown in
Figure 5-3 on page 19.
In this case the communication interface to the maXTouch device is not driven by the host system. The RESET and
CHG pins are connected to VddIO using suitable pull-up resistors. Vdd is powered up, followed by VddIO, no more than
10 ms after Vdd. Due to the pull-up resistors, RESET and CHG will rise with VddIO. The internal POR system ensures
reliable boot up of the device and the CHG line will go low approximately 35 ms after Vdd to notify the host that the
device is ready to start communication.
WARNING The device should be rese t only by using the RE SET line. If an a ttempt is ma de to reset by removing
the power from the device without also sending the signal lines low, power will be drawn from the
interface lines and the device will not reset correctly.
(Nom)
AVdd
(Nom)
VddIO
(VddIO)
RESET
RESET d asserted before AVdd ate
nominal level
Vdd (Nom)
2019 Microchip Technology Inc. DS40001922C-page 19
MXT336U 1.0
FIGURE 5-3: POWER-UP SEQUENCE
5.2.1 SUMMARY
The power-up and reset requirements for the maXTouch devices are summarized in Table 5-1.
RESET
VddIO
> 90 ms
Vdd
< 10 ms
CHG
No External drive. Pull-up resistor to VddIO on andRESET CHG
RESET CHGwhen VddIO rises, and rise with VddIO
TABLE 5-1: POWER-UP AND RESET REQUIREMENTS
Condition External RESET VddIO Delay
(After Vdd) AVdd Power-Up Comments
1 Low at Power-up 0 ms Before RESET is
released If AVdd bring-up is delayed then additional
actions will be required by the host. See notes
in Figure 5-1 on page 17
2 Not driven <10 ms Before VddIO
MXT336U 1.0
DS40001922C-page 20 2019 Microchip Technology Inc.
6.0 DETAILED OPERATION
6.1 Touch Detection
The mXT336U allows for both mutual and self capacitance measurements, with the self capacitance measurements
being used to augment the mutual capacitance measurements to produce reliable touch information.
When self capacitance measurements are enabled, touch classification is achieved using both mutual and self
capacitance touch data. This has the advantage that both types of measurement systems can work together to de tect
touches under a wide variety of circumstances.
Mutual capacitance touch data is used wherever possible to classify touches as this has greater granularity than self
capacitance measurements and provides positional information on touches.
Self capacitance measurements, on the other hand, allow for the detection of single touches in extreme cases, such as
single thick glove touches, when touches can only be detected by self capacitance data and may be missed by mutual
capacitance touch detection.
6.2 Operational Modes
The device operates in two modes: Active (touch detected ) and Idle (no touches detected). Both modes operate as a
series of burst cycles. Each cycle consists of a short burst (during which measurements are taken) followed by an
inactive sleep period. The difference between these modes is the length of the cycles. Those in idle mode typically have
longer sleep periods. The cycle length is configured using the IDLEACQINT and ACTVACQINT settings in the Power
Configuration T7. In addition, an Active to Idle Timeout setting is provided.
6.3 Detection Integrator
The device features a touch detection integration mechanism. This acts to confirm a detection in a rob ust fashion. A
counter is incremented each time a touch has exceeded its threshold and has remained above the threshold for the
current acquisition. When this counter reaches a preset limit the sensor is finally declared to be touched. If, on any
acquisition, the signal is not seen to exceed the threshold level, the counter is cleared and the process has to start from
the beginning.
The detection integrator is configured using the appropriate touch objects (Multiple Touch Touchscreen T100, Key Array
T15).
6.4 Sensor Acquisition
The charge time is set using the Acquisition Configuration T8 object.
A number of factors influence the acquisiti on ti me for a single drive line and the total acquisition time for the sensor as
a whole must not exceed 250 ms. If this condition is not met, a SIGERR will be reported.
Care should be taken to configure all the objects that can affect the measurement timing, for example, Acquisition
Configuration T8, CTE Configuration T46 and Self Capacitance Configuration T111, so that these limits are not
exceeded.
6.5 Calibration
Calibration is the process by which a sensor chip assesses the background capacitance on each node. Nodes are only
calibrated on reset and when:
• The node is enabled (that is, activated)
or
• The node is already enabled and one of the following applies:
- The node is held in detect for longer than the Touch Automati c Calibration setting (TCHAUTOCAL in the
Acquisition Configuration T8 object)
- The si gnal delta on a node is at least the touch threshold (TCHTHR – TCHHYST) in the anti-touch direction,
while it meets the criteria in the Touch Recovery Processes that results in a recalibration and Self
Capacitance Configuration T111
- The host issues a recalibrate command
- Certain configuration settings are changed
2019 Microchip Technology Inc. DS40001922C-page 21
MXT336U 1.0
A status message is generated on the start and completion of a calibration.
Note that the device performs a global calibration; that is, all the nodes are calibrated tog ether.
6.6 Digital Filtering and Noise Suppression
The mXT336U supports on-chip filtering of the acquisition data received from the sensor. Specifically, the Noise
Suppression T72 object provides an algorithm to suppress the effects of noise (for example, from a noisy charger
plugged into the user’s product). This algorithm can automatically adjust some of the acquisition parameters on-the-fly
to filter the analog-to-digital conversions (ADCs) received from the sensor.
Additional noise suppression is provided by the Self Capacitance Noise Suppression T108 object. Similar in both design
and configuration to the Noise Suppression T72 object, the Self Capacitance Noise Suppression T108 object is the
noise suppression interface for self capacitance touch measurements.
Noise suppression is triggered when a noise source is detected.
• A hardware trigger can be implemented using the NOISE_IN pin.
• The host driver code can indicate when a noise source is present.
• The noise suppression is also triggered based on the noise levels detected using internal line measurements.The
Noise Suppression T72 and Self Capaci tance Noise Suppression T108 object selects the appro priate controls to
suppress the noise present in the system.
6.7 Shieldless Support and Display Noise Suppression
The mXT336U can suppo rt shieldless sensor design even with a noisy LCD.
Display noise suppression allows the device to overcome display noise simultaneously with external noise. This feature
is based on filtering provided by the Lens Bending T65 object (see Section 6.10 “Lens Bending”).
6.8 Retransmission Compensation
The device can limit the undesirable effects on the mutual capacit ance touch signals caused by poor device coupling to
ground, such as poor sensitivity and touch break-up. This is achieved using the Retransmission Compensation T80
object. This object can be configured to allow the touchscreen to compensate for signal degradation due to these
undesirable effects. If self capacitance measurements are also scheduled, the Retransmission Compensation T80
object will use the resultant data to enhance the compensation process.
The Retransmission Compensation T80 object is also capable of compensating for water presence on the sensor if self
capacitance measurements are scheduled. In this case, both mutu al capacitance and self capacitance measurements
are used to detect moisture and then, once moisture is detected, self capacitance measurements are used to detect
single touches in the presence of moisture.
6.9 Grip Suppression
The device has two grip suppression mech anisms to suppress false detections from a user’s grip.
Mutual grip suppression works by specifying a boundary around a touchscreen, within which touches can be
suppressed whilst still allowing touches in the center of the touchscreen. This ensures that a “rolling” hand touch (such
as when a user grips a mobile device) is suppressed. A “real” (finger) touch towards the center of the screen is allowed.
Mutual grip suppression is configured using the Grip Suppression T40 object. There is one instance of the Grip
Suppression T40 object for each Multipl e Touch Touchscreen T100 object present on the device.
Self Capacitance grip suppression works by looking for characteristic shapes in the self capacitance measurement
along the touchscreen boundary, and thereby distinguishing between a grip and a touch further into the sensor.
6.10 Lens Bending
The device supports algorithms to eliminate disturbances from the measured signal.
When the sensor suffers from the screen deformation (lens bendi ng) the signal values ac quired by normal procedure
are corrupted by the disturbance component (b end). The amount of bend depends on:
• The mechanical and electrical characteristics of the sensor
• The amount and location of the force applied by th e us er touch to the sensor
MXT336U 1.0
DS40001922C-page 22 2019 Microchip Technology Inc.
The Lens Bending T65 object measures the bend component and compensates for any distortion caused by the
bend. As the bend component is primarily influenced by the user touch force, it ca n be u sed as a secondary source to
identify the presence of a touch. The additional benefit of the Lens Bending T65 object is that it will eliminate LCD noise
as well.
6.11 Glove Detection
The device has glove detection algorithms that process the measurement data received from the touchscreen
classifying touches as potential gloved touches.
The Glove Detection T78 object is used to detect glove touches. In Normal Mode the Glove Detection T78 object applies
vigorous glove classification to small signal touches to minimize the effect of unintentional hovering finger reporting.
Once a gloved touch is found, the Glove Detection T78 object enters Glove Confidence Mode. In this mode the device
expects the user to be wearing gloves so the classification process is much less stringent.
6.12 Stylus Support
The mXT336U allows for the particular characteristics of passive stylus touches, whilst still allowing conventional finger
touches to be detected. The touch sensitivity and threshold controls for stylus touches a re configured separately from
those for conventional finger touches so that both types of touch es can be accommodated.
S tylus support ensures that the small touch area of a stylus registers as a touch, as this would otherwise be considered
too small for the touchscreen. Additionally, there are controls to distinguish a stylus touch from an unwanted
approaching finger (such as on the hand holding the stylus).
Passive stylus touches are configured by the Passive Stylus T47 object. There is one instance of the Passive Stylus
T47 object for each Multiple Touch Touchscreen T100 object present on the device.
6.13 Unintentional Touch Suppression
The Touch Suppression T42 object provides a mechanism to suppress false detections from unintentional touches from
a large body area, such as from a face, ear or palm. The Touch Suppression T42 object also provides Maximum Touch
Suppression to suppress all touches if more than a specified number of touches has been detected. There is one
instance of the Touch Suppression T42 object for each Multiple Touch Touchscreen T100 object present on the device.
6.14 Adjacent Key Suppression Technology
Adjacent Key Suppression (AKS) technology is a patented method used to detect which touch object is touched when
objects are located clos e together. A touch in a group of AKS objects is only indicated on the object in that group that is
touched first. This is assumed to be the intende d ob ject. Once a n object in a n AKS group is in d etect, there can be no
further detections within that group until the object is released. Objects can be in more than one AKS group.
Note that AKS technology works best when it operates in conjunction with a detect integration setting of several
acquisition cycles.
The device has two levels of AKS. The first level works between the touch objects (Multiple Touch Touchscreen T100
and Key Array T15). The touch objects are assigned to AKS groups. If a touch occurs within one of the touch objects in
a group, then touches within other obj ects inside that group are supp ressed. For e xample , if a touchscreen and a Key
Array are placed in the same AKS group, then a touch in the touchscreen will suppress touches in the Key Array, and
vice versa.
The second level of AKS is internal AKS within an individual Key Array object (note that internal AKS is not present on
other types of touch objects, only a Key Array T15). If internal AKS is enabled, then when one key is touched, touches
on all the other keys within the Key Array are suppressed.
AKS is configured using the touch objects (Multiple Touch Touchscreen T100 or Key Array T15).
NOTE If a touch is in detect and then AKS is enabled, that touch will not be forced out of detect. It will not go out
of detect until the touch is released. AKS will then operate normally. This applies to both levels of AKS.
2019 Microchip Technology Inc. DS40001922C-page 23
MXT336U 1.0
7.0 I2C COMMUNICATIONS
The device can use an I 2C interface for communication.
The I2C interface is used in con junction with the C HG line. Th e CHG lin e going a ctive signi fies that a new data packet
is available. This provides an interrupt-style interface and allows the device to present data packets when internal
changes have occurred.
7.1 I2C Address
The device supports one I2C device address – 0x4A.
The I2C address is shifted left to form the SLA+W or SLA+R address when transmitted over the I2C interface, a s shown
in Table 7-1.
7.2 Writing To the Device
A WRITE cycle to the device consists of a START condition followed by th e I2C address of the device (SLA+W). The
next two bytes are the address of the location into which the writing starts. The first byte is the L east Significant Byte
(LSByte) of the address, and the second byte is the Most Significant Byte (MSByte). This address is then stored as the
address pointer.
Subsequent bytes in a multi-byte transfer form the actual data. These are written to the location of the address pointer,
location of the a ddress pointer + 1, location of the address pointer + 2, and so on. The address pointer returns to its
starting value when the WRITE cycle STOP condition is detected.
Figure 7-1 shows an example of writing four bytes of data to contiguous addresses starting at 0x1234.
FIGURE 7-1: EXAMPLE OF A FOUR-BYTE WRITE STARTING AT ADDRESS 0X1234
7.3 I2C Writes in Checksum Mode
In I2C checksum mode an 8-bit CRC is added to all I2C writes. The CRC is sent at the end of the data write as the last
byte before the STOP condition. All the bytes sent are included in the CRC, including the two address bytes. Any
command or data sent to the device is processed even if the CRC fails.
To indicate that a checksum is to be sent in the write, the most significant bit of the MSByte of the address is set to 1.
For example, the I2C command shown in Figure 7-2 writes a value of 150 (0x96) to address 0x1234 with a checksum.
The address is changed to 0x9234 to indicate checksu m mode.
FIGURE 7-2: EXAMPLE OF A WRITE TO ADDRESS 0X1234 WITH A CHECKSUM
TABLE 7-1: FORMAT OF AN I2C ADDRESS
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Address: 0x4A Read/write
Write Data
START SLA+W 0x34 0x12 0x96 0x9B 0xA0 0xA5 STOP
Write Address
(LSB MSB)
Write Data
START SLA+W 0x34 0x92 0x96 Checksum
Write Address
(LSB, MSB)
STOP
MXT336U 1.0
DS40001922C-page 24 2019 Microchip Technology Inc.
7.4 Reading From the Device
Two I2C bus activities must take place to read from the device. The first activity is an I2C write to set the address pointer
(LSByte then MSByte). The second activity is the actual I2C read to receive the data. The address pointer returns to its
starting value when the read cycle NACK is detected.
It is not necessary to set the address pointer before every read. The address pointer is updated automatically after every
read operation. The address pointer will be correct if the reads occur in order. In particular, when reading multiple
messages from the Message Processor T5 object, the address pointer is automatically reset to allow continuous
reads (see Section 7.5 “Reading Status Messages with DMA”).
The WRITE and READ cycles consist of a START condition followed by the I2C address of the device (SLA+W or
SLA+R respectively). Note that in this mode, calculating a checksum of the data packets is not supported.
Figure 7-3 shows the I2C commands to read four bytes starting at address 0x1234.
FIGURE 7-3: EXAMPLE OF A FOUR-BYTE READ STARTING AT ADDRESS 0X1234
7.5 Reading Status Messages with DMA
The device facilitates the easy reading of multiple messages using a single continuous read operation. This allows the
host hardware to use a direct memory access (DMA) controller for the fast reading of messages, as follows:
1. The host uses a write operation to set the address pointer to the start of the Message Count T44 object, if
necessary. Note that the STOP condition at the end of the read resets the add ress pointer to its initial l ocation,
so it may already be pointing at the Message Count T44 object following a previous message read. If a checksum
is required on each message, the most significant bit of the MSByte of the read address must be set to 1.
2. The host starts the read operation of the messa g e by sending a START conditio n.
3. The host reads the Message Count T44 object (one byte) to retrieve a count of the pending messages.
4. The host ca lculates the number o f bytes to read by multiplying the messa ge count by the size of the Messa ge
Processor T5 object. Note that the ho st shoul d h ave al read y read the size of the Message Pro cessor T5 object
in its initialization code.
5. Note that the size of the Message Processor T5 object as recorded in the Object Table includes a checksum byte.
If a checksum has not been requested, one byte should be deducted from the size of the object.
That is: number of bytes = count × (size – 1).
6. The host reads the calculated number of message bytes. It is important that the host does not send a STOP
condition during th e message read s, as this will terminate the continuous read operation and reset the address
pointer. No START and STOP conditions must be sent between the messages.
7. The host sends a STOP condition at the end of the read operation a fter the last message has been read. The
NACK condition immediately before the STOP condition resets the address pointer to the start of the Message
Count T44 object.
Read Data
START SLA+R 0x96 0x9B 0xA0 0xA5 STOP
START SLA+W 0x34 0x12
Read Address
(LSB, MSB)
Set Address Pointer
Read Data
STOP
2019 Microchip Technology Inc. DS40001922C-page 25
MXT336U 1.0
Figure 7-4 shows an example of using a continuo us read operat ion to rea d three messages from the device without a
checksum. Figure 7-5 on page 26 shows the same example with a checksum.
FIGURE 7-4: CONTINUOUS MESSAGE READ EXAMPLE – NO CHECKSUM
START SLA+W LSB MSB
Start Address of
Message Count Object
STOP
Set Address Pointer
Read Message Count
START SLA+R Count = 3
Message Count Object
Read Message Data
Report ID Data Data
Message Processor Object Message # 1–
( 1) bytes
size
–
Report ID Data Data
Message Processor Object Message # 2–
Report ID Data Data
Message Processor Object Message # 3–
STOP
Continuous
Read
MXT336U 1.0
DS40001922C-page 26 2019 Microchip Technology Inc.
FIGURE 7-5: CONTINUOUS MESSAGE READ EXAMPLE – I2C CHECKSUM MODE
There are no checksums added on any other I2C reads. An 8-bit CRC can be added, however, to all I2C writes, as
described in Section 7.3 “I2C Writes in Checksum Mode”.
An alternative method of reading messages using the CHG line is given in Section 7.6 “CHG Line”.
7.6 CHG Line
The CHG line is an active-low, open -drain output that is used to alert the host that a n ew message is available in the
Message Processor T5 object. This provides the host with an interrupt-style interface with the potential for fast response
times. It reduces the need for wasteful I2C communications.
The CHG line should al ways be confi gured as an input on the host d uring norma l usage. This is particularly important
after power-up or reset (see Section 5.0 “Power-up / Reset Requirements”).
A pull-up resistor is required to VddIO (see Section 2.0 “Schematics”).
The CHG line operates in two modes, as defined by the Communica tions Configuration T18 object.
Report ID Data Data Checksum
Report ID Data Data Checksum
Start Address of
Message Count Object
Set Address Pointer
Read Message Count
START SLA+R Count = 3
Message Count Object
Read Message Data
Message Processor Object –Message # 1
size bytes
Message Processor Object –Message # 2
Message Processor Object –Message # 3
STOP
Continuous
Read
START SLA+W LSB MSB | 0x80 Checksum STOP
Report ID Data Data Checksum
2019 Microchip Technology Inc. DS40001922C-page 27
MXT336U 1.0
FIGURE 7-6: CHG LINE MODES FOR I2C-COMPATIBLE TRANSFERS
In Mode 0 (edge-triggered operation):
1. The CHG line goes low to indicate that a message is present.
2. The CHG line goes high when the first byte of the first message (that is, its report ID) has been sent and
acknowledged (ACK sent) and the next byte has been prepared in the buffer.
3. The STOP condition at the end of an I2C transfer causes the CHG line to stay high if there are no more messages.
Otherwise the CHG li ne goes low to indicate a further message.
Note that Mode 0 also allows the host to continually read messages by simply continuing to read bytes back without
issuing a STOP condition. Message reading should end when a report ID of 255 (“invalid message”) is received.
Alternatively the host ends the transfer by sending a NACK after receiving the last byte of a message, followed by a
STOP condition. If there is another message present, the CHG line goes low again, as in step 1. In this mode the state
of the CHG line does not need to be checked during the I2C read.
In Mode 1 (level-triggered operation ):
1. The CHG line goes low to indicate that a message is present.
2. The CHG line remains lo w while there ar e further messages to be sent after the current message.
3. The CHG line goes high again only on ce the first byte of th e last message (that is, its report ID) has been sent
and acknowledged (ACK sent) and the next byte has been pr epared in the output buffer.
Mode 1 allows the host to contin ually read the messages un til the CHG line goes hig h, and the state of the CHG line
determines whether or not the host should continue receiving messages from the device.
The Communications Configuration T18 object can be used to configure the behavior of the CHG line. In addition to the
CHG line operation modes described above, this object allows direct control over the state of the CHG line.
7.7 SDA and SCL
The I2C bus transmits data and clock with SDA and SCL, respectively. These are open-drain. The device can only drive
these lines low or leave them open. The termination resistors (Rp) pull the line up to VddIO if no I2C device is pulling it
down.
The termination resistors should be chose n so tha t the rise times on SDA and SCL meet the I2C specifications for the
interface speed being used, bearing in mind other loads on the bus. For b est laten cy performan ce, it is recommended
that no other devices share the I2C bus with the maXTouch controller.
NOTE The state of the CHG line should be checked only between messages and not between the bytes of a
message. The precise point at which the CHG line changes state cannot be predicted and so the state of
the CHG line cannot be guaranteed between by tes.
Bn
…
B1B0Bn
…
B1B0 Bn
…
B1B0 STOPSTART SLA-R
I C Interface
2ACK NACK
…
Message #1 Message #2 Message #m
CHG Line
Mode 0
CHG line high or low; see text
Bn
…
B1B0Bn
…
B1B0 Bn
…
B1B0 STOPSTART SLA-R
I C Interface
2ACK
…
Message #1 Message #2 Message #m
CHG Line
Mode 1
CHG line high or low; see text
…
…
MXT336U 1.0
DS40001922C-page 28 2019 Microchip Technology Inc.
7.8 Clock Stretching
The device sup ports clock stretching in acco rdance with the I2C specification. It may also instigate a clock stretch if a
communications event happens during a period when the device is busy internally. The maximum clock stretch is
approximately 10–15ms.
2019 Microchip Technology Inc. DS40001922C-page 29
MXT336U 1.0
8.0 PCB DESIGN CONSIDERATIONS
8.1 Introduction
The following sections g ive the design consid erations that should be adh ered to when desig ning a PCB layout for use
with the mXT336U. Of these, power supply and ground tracking conside ra ti ons are the most critical.
By observing the following design rules, and with careful preparation for the PCB layout exercise, designers will be
assured of a far better chance of success and a correctly functioning product.
8.2 Printed Circuit Board
Microchip recommends the use of a four-layer printed circuit board for mXT336U applications. This, together with
careful layout, will ensure that the board meets relevant EMC requirements for both noise radiation an d susceptibility,
as laid down by the various national and international standards agencies.
8.2.1 PCB CLEANLINESS
Modern no-clean-flux is generally compatible with capacitive sensing circuits.
8.3 Power Supply
8.3.1 SUPPLY QUALITY
While the device has good Power Supply Rejection Ratio properties, poorly regulated and/or noisy power supplies can
significantly reduce performance.
Particular care should be taken of the AVdd supply, as it supplies the sensitive analog stages in the device.
8.3.2 SUPPLY RAILS AND GROUND TRACKING
Power supply and clock distributio n are the most critical parts of any board layout. Becaus e of thi s, it is advisable that
these be completed before any other tracking is undertaken. After these, supply decoupling, and analog and high speed
digital signals should be addressed. Track widths for all signals, especially power rails should be kept as wide as
possible in order to reduce inductance.
The Power and Ground pla nes themselves can form a useful capacitor. Flood filling for either or both of th ese supply
rails, therefore, should be used where possible. It is important to ensure that there are no floating copper areas
remaining on the board: all such areas should be connected to the ground plane. The flood filling should be done on the
outside layers of the board.
8.3.3 POWER SUPPLY DECOUPLING
Decoupling capacitor should be fitted as specified in Section 2.2 “Schematic Notes”.
The decoupling capacitors must be placed as close as possible to the pin being decoupled. The traces from these
capacitors to the respective device pins should be wide and take a straight route. They should be routed over a ground
plane as much as possible. The capacitor ground pins should also be connected directly to a ground plane.
Surface mounting capacitors are preferred over wire-leaded types due to their lower ESR an d ESL. It is often possible
to fit these decoupling capacitors underneath and on the opposite side of the PCB to the digital ICs. This will provide
the shortest tracking, and most effective decoupling possible.
Refer to the application note Selecting Decoupling Capacitors for Atmel PLDs (doc0484.pdf) for further general
information on decoupling capacitors.
8.3.4 VOLTAGE PUMP
The voltage pump capacitors between EXTCAP0 and EXTCAP1 (Cd on the schematic in Section 2.0 “Schematics”)
must be placed as close as possible to the EXTCAPn pins. The two traces must be kept as short and as wide as possible
for best pump performa nce. They should also be routed as parallel and as close as possible to each other in order to
reduce emissions.
CAUTION! If a PCB is reworked to correct soldering faults relating to any device, or to any associated traces or
components, be sure that you fully understand the nature of the flux used during the rework process.
Leakage currents from hygroscopic ionic residues can stop capacitive sensors from functioning. If you
have any doubts, a thorough cleaning after rework may be the only safe option.
MXT336U 1.0
DS40001922C-page 30 2019 Microchip Technology Inc.
8.4 Voltage Regulators
Each supply rail requi res a Low Drop-Out (LDO) voltage regulator, although an LDO can be share d where supply ra ils
share the same voltage level.
Figure 8-1 shows an example circuit for an LD O.
FIGURE 8-1: EXAMPLE LDO CIRCUIT
An LDO regulator should be chosen that provides adequate output capability, low noise, good load regulation and step
response. The voltage regulato rs listed i n Table 8-1 have been tested and fo und to work well with maXTouch devices.
If it is desired to use an alternative LDO, however, certain performance criteria should be verified before using the
device. These are:
• Stable with high value multi-layer ceramic capacitors on the output
• Low output noise – less than 100 µV RMS over the range 10 Hz to 1 MHz
• Good load transient response – this should be less than 35 mV peak when a lo ad step change of 100 mA is
applied at the device output terminal
.
8.4.1 SINGLE SUPPLY OPERATION
When designing a PCB for an application using a single LDO, extra care should be taken to ensure short, low inductance
traces between the supply and the touch controller supply input pins. Ideally, tracking for the individual supplies should
be arranged in a star configuration, with the LDO at the junction of the star . This will ensure that supply current variations
or noise in one supply rail will ha ve minimum effect on the other supplies. In applications where a g round plane is not
practical, this same star layout should also apply to the power supp ly ground returns.
TABLE 8-1: SUITABLE LDO REGULATORS
Manufacturer Device Current Rating (mA)
Microchip Technology Inc. MCP1824 300
Microchip Technology Inc. MCP1824S 300
Microchip Technology Inc . MAQ5300 300
Microchip Technology Inc. MCP1725 500
Microchip Technology Inc. MIC5323 300
Analog Devices ADP122/ADP123 300
Diodes Inc. AP2125 300
Diodes Inc. AP7335 300
Linear Technology LT1763CS8-3.3 500
NXP LD6836 300
Texas Instruments LP3981 300
Note: Some manufacturers claim that minimal or no capacitance is required for correct regulator operation. However, in all
cases, a minimum of a 1.0 µF ceramic, low ESR capacitor at the input and output of these devices should be used. The
manufacturer’s datasheets should always be referred to when selecting capacitors for these devices and the typical
recommended values, types and dielectrics adhered to.
SUPPLY FROM HOST
GNDGND GND
VIN
SHDN
VOUT
SENSE/ADI
GND
BYP
SUPPLY TO MAXTOUCH DEVICE
2019 Microchip Technology Inc. DS40001922C-page 31
MXT336U 1.0
Only regulators with a 300 mA or greater rating can be used in a single-supply design.
Refer to the following application note for more information on routing with a sing le LDO:
• Application Note: MXTAN0208 – Design Guide for PCB Layouts for Atmel Touch Controllers
8.4.2 MULTIPLE VOLTAGE REGULATOR SUPPLY
The A Vdd supply stability is critical for the device because this supply interacts directly with the analog front end. If noise
problems exist when using a single LDO regulator, Microchip recommends that AVdd is supplied by a regulator that is
separate from the digital supply. This reduces the amount of noise injected into the sensitive, low signal level parts of
the design.
8.5 I2C Line Pull-up Resistors
The values for pull-up re sistors on SDA and SCL need to be chosen to ensure rise times are within I2C spe cification.
If the rise time is too long the overall clock rate will be reduced.
8.6 Analog I/O
In general, tra cking for the an alog I/O si gnals from the de vice sh ould be kept as short as possib le. These no rmally go
to a connector which interfaces directly to the touchscreen.
Ensure that adequate ground-planes are used. An analog ground plane should be used in addition to a digital one. Care
should be taken to ensure that both ground planes are kept separate and are connected togeth er only at the point of
entry for the power to the PCB. This is usually at the input connector.
8.7 Component Placement and Tracking
It is important to orient all devices so that the tracking for important signals (such as power and clocks) are kept as short
as possible.
8.7.1 DIGITAL SIGNALS
In general, when tracking digital signals, it is advisable to avoid sharp directional changes on sensitive signal tracks
(such as analog I/O) and any clock or crystal tracking.
A good ground return path for all signals should be provided, where possible, to ensure that there are no discontinuities.
8.7.2 QFN PACKAGE RESTRICTIONS
The central pad on the underside of the QFN device should be connected to ground. Do not run any tracks underneath
the body of the device, onl y ground. Figure 8-2 shows examples of good and bad tracking.
FIGURE 8-2: EXAMPLES OF GOOD AND BAD TRACKING
Good Tracking Bad Tracking
Note: The number of
pins and their functions
is shown for example
purposes only and may
not reflect the actual
number or function on
the device.
MXT336U 1.0
DS40001922C-page 32 2019 Microchip Technology Inc.
8.8 EMC and Other Observations
The following recommendations are no t manda tory, but may help in situations where particularly difficult EMC or other
problems are present:
• T ry to keep as many signals as possible on the inside layers of the board. If suitable ground flood fills are used on
the top and bottom layers, these will provide a good level of screening for noisy signals, both into and out of the
PCB.
• Ensure that the on-board regulato r s have sufficient tracking around and underneath the devices to act as a
heatsink. This heatsink will normally be connected to the 0 V or ground supply pin. Increasing the width of the
copper tracking to any of the device pins will aid in removing heat. There should be no solder mask over the
copper track underneath the body of the regulators.
• Ensure that the decoupling capacitors, especially high capacity ceramic type, have the requisite low ESR, ESL
and good stability/temperature properties. Refer to the regulator ma nufacturer’s datasheet for more information.
2019 Microchip Technology Inc. DS40001922C-page 33
MXT336U 1.0
9.0 GETTING STARTED WITH MXT336U
9.1 Establishing Contact
9.1.1 COMMUN ICAT I ON WITH THE HOST
The host can use the following interface to communicate with the device:
•I
2C interface (see Section 7.0 “I2C Communications”)
9.1.2 POWER-UP SEQUENCE
On power-up, the CHG line goes low to indicate that there is new data to be read from the device. If the CHG line does
not go low, th ere is a problem with the device.
The host should a ttempt to read any available messages to establish that the device is present and running followi ng
power-up or a reset. Examples of messages include reset or calibration messages. The host should also check that
there is no configuration error reported.
9.2 Using the Object Protocol
The device has an object-based protocol that is used to communicate with the device. Typical communication includes
configuring the device, sending commands to the device, and receiving messages from the device.
The host must perform the following initialization so that it can communicate with the device:
1. Read the start positions of all the objects in the device from the Object Table and build up a list of these
addresses.
2. Use the Object Table to calculate the report IDs so that messages from the device can be correctly interpreted.
9.2.1 CLASSES OF OBJECTS
The mXT336U contains the following classes of objects:
•Debug objects – prov ide a raw data output method for development and testing.
•General objects – required for global configuration, transmitting messages and receiving commands.
•Touch objects – operate on measured signals from the touch sensor and report touch data.
•Signal processing objects – process data from other objects (typically signal filtering operations).
•Support objects – provide additio nal functionality on the device.
9.2.2 OBJECT INSTANCES
TABLE 9-1: OBJECTS ON THE MXT336U
Object Description Number of
Instances Usage
Debug Objects
Diagnostic Debug T37 Allows access to diagnostic debug data to
aid development. 1 Debug commands only. No
configuration/tuning
necessary. Not for use in
production.
General Objects
Message Processor T5 Handles the transmission of messages.
This object holds a message in its memory
space for the host to read.
1 No configuration necessary.
Command Processor T6 Performs a command when written to.
Commands include reset, calibrate and
backup settings.
1 No configuration necessary.
Power Configuration T7 Controls the sleep mode of the device.
Power consumption can be lowered by
controlling the acquisition frequency and
the sleep time between acquisitions.
1 Must be configured before
use.
Acquisition Configuration T8 Controls how the device takes each
capacitive measurement. 1 Must be configured before
use.
MXT336U 1.0
DS40001922C-page 34 2019 Microchip Technology Inc.
Touch Objects
Key Array T15 Creates a rectangular array of keys. A Key
Array T15 object reports simple on/off
touch information.
1 Enable and configure as
required.
Multiple Touch Touchscreen
T100 Creates a Touchscreen that supports the
tracking of more than one touch. 1 Enable and configure as
required.
Signal Processing Objects
Grip Suppression T40 Suppresses false detections caused, for
example, by the user gripping the edge of
the touchscreen.
1 Enable and configure as
required.
Touch Suppression T42 Suppresses false detections caused, for
example, by the user placing their face too
near the touchscreen on a mobile phone.
1 Enable and configure as
required.
Passive Stylus T47 Processes passive stylus input. 1 Enable and configure as
required.
Shieldless T56 Allows a sensor to use true single-layer
co-planar construction. 1 Enable and configure as
required.
Lens Bending T65 Compensates for lens deformation (lens
bending) by attempting to eliminate the
disturbance signal from the reported
deltas.
3 Enable and configure as
required.
Noise Suppression T72 Performs various noise reduction
techniques during touchscreen signal
acquisition.
1 Enable and configure as
required.
Glove Detection T78 Allows for the reporting of glove touches. 1 Enable and configure as
required.
Retransmission
Compensation T80 Limits the negative effects on touch
signals caused by poor device coupling to
ground.
1 Enable and configure as
required.
Unlock Gesture T81 Sends a message when a gesture
satisfies the configuration settings for use
in wake up or unlock situations.
4 Enable and configure as
required.
Touch Sequence Processor
T93 Captures a sequence of touch and release
locations to allow double taps to be
detected.
1 Enable and configure as
required.
Self Capacitance Noise
Suppression T108 Suppresses the effects of external noise
within the context of self capacitance
touch measurements.
1 Enable and configure as
required.
Symbol Gesture Processor
T115 Detects arbitrary shaped gestures as a
series of ordinal strokes. These are
typically symbols drawn by the user for
interpretation by the host as wake-up
gestures or other application triggers.
1 Enable and configure as
required.
Sensor Correction T121 Allows adjustments to be made to mutual
measurements from an associated
touchscreen sensor.
1 Enable and configure as
required.
Support Objects
Communications
Configuration T18 Configures additional communications
behavior for the device. 1 Check and configure as
necessary.
Self Test T25 Configures and performs self-test routines
to find faults on a touch sensor. 1 Configure as required for
pin test commands.
User Data T38 Provides a data storage area for user
data. 1 Configure as required.
Message Count T44 Provides a count of pending messages. 1 Read-only object.
TABLE 9-1: OBJECTS ON THE MXT336U (CONTINUED)
Object Description Number of
Instances Usage
2019 Microchip Technology Inc. DS40001922C-page 35
MXT336U 1.0
9.2.3 CONFIGURING AND TUNING THE DEVICE
The objects are designed such that a default value of zero in their fields is a “safe” value that typically disables
functionality. The ob jects must be configure d before use and the settings written to th e non-vola tile memory using the
Command Processor T6 object.
Perform the following actions for each object:
1. Enable the object, if the object requires it.
2. Configure the fi elds in the object, as required.
3. Enable reporting, if the obje c t supports messages, to receive messages from the object.
9.3 Writing to the Device
The following mechanisms can be used to write to the device:
• Using an I2C write operation (see Section 7.2 “Writing To the Device”).
Communication with the device is achieved by writing to the appropriate object:
• To send a command to the device, an appropriate command is written to the Command Processor T6 object.
CTE Configuration T46 Controls the capacitive touch engine for
the device. 1 Must be configured.
Timer T61 Provides control of a timer. 6 Enable and configure as
required.
Serial Data Command T68 Provides an interface for the host driver to
deliver various data sets to the device. 1 Enable and configure as
required.
Dynamic Configuration
Controller T70 Allows rules to be defined that respond to
system events. 20 Enable and configure as
required.
Dynamic Configuration
Container T71 Allows the storage of user configuration on
the device that can be selected in run-time
based on rules defined in the Dynamic
Configuration Controller T70 object.
1 Configure if Dynamic
Configuration Controller T70
is in use.
CTE Scan Configuration
T77 Configures enhanced X line scanning
features. 1 Enable and configure as
required.
Auxiliary Touch
Configuration T104 Allows the setting of self capacitance gain
and thresholds for a particular
measurement to generate auxiliary touch
data for use by other objects.
1 Enable and configure if
using self capacitance
measurements
Self Capacitance Global
Configuration T109 Provides configuration for a self
capacitance measurements employed on
the device.
1 Check and configure as
required (if using self
capacitance
measurements).
Self Capacitance Tuning
Parameters T110 Provides configuration space for a generic
set of settings for self capacitance
measurements.
4 Use under the guidance of
Microchip field engineers
only.
Self Capacitance
Configuration T111 Provides configuration for self capacitance
measurements employed on the device. 2 Check and configure as
required (if using self
capacitance
measurements).
Self Capacitance
Measurement Configuration
T113
Configures self capacitance
measurements to generate data for use by
other objects.
1 Enable and configure as
required.
Symbol Gesture
Configuration T116 Stores configuration data that defines the
symbols to be detected by the Symbol
Gesture Processor T115 object.
1 Configure if Symbol Gesture
Processor T115 is in use.
TABLE 9-1: OBJECTS ON THE MXT336U (CONTINUED)
Object Description Number of
Instances Usage
MXT336U 1.0
DS40001922C-page 36 2019 Microchip Technology Inc.
• To configure the device, a configuration parameter is written to the appropriate object. For example, writing to the
Power Configuration T7 configures the power consumpti on for the device and writing to the touchscreen Multiple
Touch Touchscreen T100 object sets up the touchscreen. Some objects are optional and need to be enabled
before use.
9.4 Reading from the Device
Status information is stored in the Message Processor T5 object. This object can be read to receive any status
information from the device. The following mechanisms provide an interrupt-style interface for reading messages in the
Message Processor T5 object:
• The CHG line is asserted whenever a new message is available in the Message Processor T5 object (see
Section 7.6 “CHG Line”). See Section 7.4 “Reading From the Device” for information on the format of the I2C read
operation.
Note that the host should always wait to be notified of messages. The host should not poll the device for messages.
IMPORTANT! When the host issues any command within an object that results in a flash write to the device Non-
Volatile Memory (NVM), that object should have its CTRL RPTEN bit set to 1, if it has one (For
example, from the following objects: Command Processor T6, Serial Data Command T68, Self
Capacitance Global Configuration T109). This ensu res that a message from the object writing to
the NVM is generated at the completion of the process and an assertion of the CHG line is
executed.
The host must also ensure that the assertion of the CHG line refers to th e expected object report
ID before asserting the RESET line to perform a reset. Failure to follow this guidance may result in
a corruption of device configuration area and the generation of a CFGERR.
2019 Microchip Technology Inc. DS40001922C-page 37
MXT336U 1.0
10.0 DEBUGGING AND TUNING
10.1 SPI Debug Interface
10.2 Secondary Debug Interface
This interface is used for low-level debugging when developing the system.
The interface consists of the DBG2_CLK, DBG2_FRAME and DBG2_DATA0 to DBG2_DATA5 lines.
These pins should be routed to test points on designs where a new sensor or display technology is being used, or if the
design will use an active stylus. These lines should not be connected to power or GND.
The touch controller will take care of the pin configuration. When these lines are in use, any alternative function for the
pins cannot be used.
The secondary interface i s enabled by a special firmware build and by default will be off.
10.3 Object-based Protocol
The device provides a mechanism for obtaining debug data for development and testing purposes by reading data from
the Diagnostic Debug T37 object.
Note that the Diagnostic Debug T37 is of most use for simple tuning purposes. When debugging a design, it is preferable
to use the SPI Debug Interface, as this will have a much higher bandwidth and can provide real-time data.
10.4 Self Test
There is a Self Test T25 object th at runs self-test routines in the device to find hard ware faults on the sense lines and
the electrodes. This object also performs an initial pin fault test on power-up to ensure that there is no X-to-Y short before
the high-voltage supply is enabled inside the chip. A high-voltage short on the sense lines would break the device.
This interface is used for tuning and debugging when running the system and allows the development engineer to use
Microchip maXTouch Studi o to read the real-time raw data. This uses the low-l evel debug port, accessed via the SPI
interface.
The SPI Debug Interface consists of the DBG_SS, DBG_CLK, and DBG_DA TA lines. It is recommended that these pins
are routed to test points on all designs such that they can be connected to external hardware during system
development. These lines should not be connected to power or GND.
The SPI Debug Interface is ena bled by the Command Processor T6 object and by default will be off.
NOTE The touch controller will take care of the pin configuration. When the DBG_SS , DBG_CLK, and
DBG_DATA lines are in use for de bugging, any alternative function for the pins cannot be used.
Note that the Diagnostic Debug T37 is of most use for simple tuning purposes. When debugging a design, it is preferable
to use the SPI Debug Interface, as this will have a much higher bandwidth and can provide real-time data.
MXT336U 1.0
DS40001922C-page 38 2019 Microchip Technology Inc.
11.0 SPECIFICATIONS
11.1 Absolute Maximum Specifications
11.2 Recommended Operating Conditions
11.2.1 DC CHARACTERISTICS
11.2.1.1 Analog Voltage Supply – AVdd
Vdd 3.6 V
VddIO 3.6 V
AVdd 3.6 V
Voltage forced onto any pin –0.3 V to (Vdd, VddIO or AVdd) + 0.3 V
Configuration parameters maximum writes 10,000
Maximum junction temperature 125C
CAUTION! Stresses beyond those listed under Absolute Maximum Spec ifications may cause permanent damage
to the device. This is a stress rating only and functional operation of the device at these or other
conditions beyond those indicated in the operational sections of this specificatio n is not implied.
Exposure to absolute maximum specification conditions for extended periods may affect device
reliability.
Operati n g te mperature –40C to +85C
Stora ge temperature –60C to +150C
Vdd 3.3 V
VddIO 1.8 V to 3.3 V
AVdd 3.3 V
XVdd with internal voltage doubler Vdd to 2 × Vdd
Cx transverse load capacitance per node 0.6 pF to 3 pF
Temperature slew rate 10C/min
Parameter Min Typ Max Units Notes
AVdd
Operating limits 3.0 3.3 3.47 V
Supply Rise Rate – – 0.036 V/µs For example, for a 3.3 V rail,
the voltage must not rise in
less than 92 µs
2019 Microchip Technology Inc. DS40001922C-page 39
MXT336U 1.0
11.2.1.2 Digital Voltage Supply – Vdd, VddIO
11.2.1.3 XVdd Voltag e Supply – XVdd
11.2.2 POWER SUPPLY RIPPLE AND NOISE
Parameter Min Typ Max Units Notes
VddIO
Operating limits 1.71 3.3 3.47 V I2C
Supply Rise Rate – – 0.036 V/µs For example, for a 3.3 V rail,
the voltage must not rise in
less than 92 µs
Vdd
Operating limits 2.7 3.3 3.47 V
Supply Rise Rate – – 0.036 V/µs For example, for a 3.3 V rail,
the voltage must not rise in
less than 92 µs
Supply Fall Rate – – 0.05 V/µs For example, for a 3.3 V rail,
the voltage must not fall in
less than 66 µs
Parameter Min Typ Max Units Notes
XVdd
Operating limits Vdd – 2 × Vdd V Maximum value with internal
voltage doubler
Parameter Min Typ Max Units Notes
Vdd – – ±50 mV Across frequency range
1Hz to 1MHz
AVdd – – ±40 mV Across frequency range
1 Hz to 1 MHz, with Noise
Suppression enabled
MXT336U 1.0
DS40001922C-page 40 2019 Microchip Technology Inc.
11.3 Test Configuration
The values listed below were used in the refere nce unit to validate the interfaces and derive the ch aracterization data
provided in the following sections.
The values for the user appli cation will d epend on th e circumstances of that particular project and will vary from th ose
listed here. Further tuning will be required to achieve an optimal performance.
TABLE 11-1: TEST CONFIGURATION
Object/Parameter Description/Setting (Numbers in Decimal)
Acquisition Configuration T8
CHRGTIME 34
MEASALLOW 11
MEASIDLEDEF 8
MEASACTVDEF 2
Key Array T15 Object Enabled
XSIZE 1
YSIZE 3
CTE Configuration T46
IDLESYNCSPERX 16
ACTVSYNCSPERX 16
Shieldless T56 Object Enabled
INTTIME 25
Lens Bending T65 Instance 0 Object Enabled
Noise Suppression T72 Object Enabled
Glove Detection T78 Object Enabled
Retransmission Compensation T80 Object Enabled
Multiple To uch Touchscreen T100 Object Enabled
XSIZE 14
YSIZE 24
Auxiliary Touch Configuration T104 Object Enabled
Self Capacitance Noise Suppression T108 Object Enabled
Self Capacitance Configuration T111 Instance 0
INTTIME 60
IDLESYNCSPERL 24
ACTVSYNCSPERL 24
Self Capacitance Configuration T111 Instance 1
INTTIME 60
IDLESYNCSPERL 32
ACTVSYNCSPERL 32
Self Capacitance Measurement Configuration T113 Object Enabled
2019 Microchip Technology Inc. DS40001922C-page 41
MXT336U 1.0
11.4 Supply Current
11.4.1 ANALOG SUPPLY
Acquisition Rate (ms) 0 Touches (mA) 1 Touch (mA) 2 Touches (mA) 5 Touches (mA)
Free-run 5.26 5.98 6.82 6.75
8 1.93 3.87 6.30 6.29
10 1.53 3.14 5.06 5.08
11 1.38 2.89 4.52 4.25
16 1.00 2.02 3.19 3.13
17 0.95 1.93 2.97 2.96
25 0.67 1.37 2.02 2.02
30 0.57 1.18 1.67 1.70
32 0.48 1.09 1.58 1.57
42 0.38 0.88 1.20 1.21
50 0.35 0.80 1.01 0.99
64 0.25 0.67 0.78 0.79
100 0.21 0.41 0.50 0.48
128 0.14 0.34 0.38 0.39
254 0.08 0.15 0.22 0.17
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Current Consumption (mA)
Acquisition Rate (ms)
0 Touches (mA)
1 Touch (mA)
2 Touches (mA)
5 Touches (mA)
MXT336U 1.0
DS40001922C-page 42 2019 Microchip Technology Inc.
11.4.2 DIGITAL SUPPLY
11.4.2.1 Vdd
Acquisition Rate (ms) 0 Touches (mA) 1 Touch (mA) 2 Touches (mA) 5 Touches (mA)
Free-run 5.18 5.71 6.01 7.35
8 1.96 3.74 5.94 7.09
10 1.61 3.04 4.54 5.54
11 1.50 2.57 4.11 4.99
16 1.01 1.94 2.85 3.46
17 0.98 1.88 2.69 3.16
25 0.65 1.29 1.83 2.19
30 0.58 1.12 1.52 1.88
32 0.55 1.06 1.42 1.74
42 0.42 0.86 1.06 1.28
50 0.35 0.74 0.91 1.11
64 0.28 0.66 0.74 0.89
100 0.16 0.46 0.46 0.53
128 0.20 0.39 0.38 0.50
254 0.12 0.18 0.19 0.25
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Current Consumption (mA)
Acquisition Rate (ms)
0 Touches (mA)
1 Touch (mA)
2 Touches (mA)
5 Touches (mA)
2019 Microchip Technology Inc. DS40001922C-page 43
MXT336U 1.0
11.4.2.2 VddIO
11.5 Deep Sleep Current
Acquisition Rate (ms) 0 Touches (mA) 1 Touch (mA) 2 Touches (mA) 5 Touches (mA)
Free-run 0.01 3.25 3.25 3.25
8 0.01 3.25 3.25 3.25
10 0.01 3.25 3.25 3.25
11 0.01 3.25 3.25 3.25
16 0.01 3.25 3.25 3.25
17 0.01 3.25 3.25 3.25
25 0.01 3.25 3.25 3.25
30 0.01 3.25 3.25 3.25
32 0.01 3.25 3.25 3.25
42 0.01 3.25 3.25 3.25
50 0.01 3.25 3.25 3.25
64 0.01 3.25 3.25 3.25
100 0.01 3.25 3.25 3.25
128 0.01 3.25 3.25 3.25
254 0.01 3.25 3.25 3.25
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Current Consumption (mA)
Acquisition Rate (ms)
0 Touches (mA)
1 Touch (mA)
2 Touches (mA)
5 Touches (mA)
TA = 25C
Parameter Min Typ Max Units Notes
Deep Sleep Current – 15 – µA Vdd = 3.3 V, AVdd = 3.3 V
Deep Sleep Power – 49 – µW Vdd = 3.3 V, AVdd = 3.3 V
MXT336U 1.0
DS40001922C-page 44 2019 Microchip Technology Inc.
11.6 Timing Specifications
11.6.1 TOUCH LATENCY
11.6.2 SPEED
0
5
10
15
20
25
123
Average Latency (ms)
T100 TCHDIDOWN
T7 = Free run, pipelining ON
T7 = Free run, pipelining OFF
0
50
100
150
200
250
12345
Refresh Rate (Hz)
Number of Moving Touches
Pipelining ON (active mode)
Pipelining OFF (active mode)
2019 Microchip Technology Inc. DS40001922C-page 45
MXT336U 1.0
11.6.3 RESET TIMINGS
11.7 Touchscreen Sensor Characteristics
11.8 Input/Output Characteristics
Parameter Min Typ Max Units Notes
Power on to CHG line low – 35 – m s Vdd supply for POR
VddIO supply for external
reset
Hardware reset to CHG line low – 38 – ms
Software reset to CHG line low – 55 – ms
Note 1: Any CHG line activity before the power-on or reset period has expired should be ignored by the host. Operation of this
signal cannot be guaranteed before the power-on/reset periods have expired.
Parameter Description
Cm Mutual capacitance Typical value is between 0.15 pF and 10 pF on a single node.
Cpx Mutual capacitance load to X Microchip recommends a maximum load of 300 pF on each X or Y
line. (1)
Cpy Mutual capacitance load to Y
Cpx Self capacitance load to X Microchip recommends a maximum load of 100 pF on each X or Y
line. (1)
Cpy Self capacitance load to Y
Cpx Self capacitance imbalance on X Nominal value is 9.7 pF. Value increases by 1 pF for every 20 pF
reduction in Cpx/Cpy (based on 100 pF load)
Cpy Self capacitance imbalance on Y
Note 1: Please contact your Microchip representative for advice if you intend to use higher values.
Parameter Description Min Typ Max Units Notes
Input (RESET)
Vil Low input logic level –0.3 – 0.3 ×
VddIO V VddIO = 1.8 V to Vdd
Vih High input logic level 0.7 ×
VddIO – VddIO V VddIO = 1.8 V to Vdd
RESET pin Internal pull-up resistor 9 10 16 k
Input (SYNC, SDA, SCL, CHG)
Vil Low input logic level –0.3 – 0.3 ×
VddIO V VddIO = 1.8 V to Vdd
Vih High input logic level 0.7 ×
VddIO – VddIO V VddIO = 1.8 V to Vdd
Iil Input leakage current – – 1 µA
Output (SCAN_OUT, DBG_CLK, DBG_DATA)
Vol Low output voltage 0 – 0.2 ×
VddIO V VddIO = 1.8 V to Vdd
Iol = max 0.4 mA
Voh High output voltage 0.8 ×
VddIO – VddIO V VddIO = 1.8 V to Vdd
Ioh = 0.4 mA
MXT336U 1.0
DS40001922C-page 46 2019 Microchip Technology Inc.
11.9 I2C Specification
More detailed information on I2C operation is available from www.nxp.com/documents/user_manual/UM10204.pdf.
11.10 Touch Accuracy and Repeatability
1
11.11 Thermal Packaging
11.11.1 THERMAL DATA
11.11.2 JUNCTION TEMPERATURE
The maximum junction temperature allowed on this device is 125C.
The average junction temperature in C (TJ) for this device can be obtained from the following:
If a cooling device is required, use this equation:
where:
•JA= package thermal resistance, Junction to ambient (C/W) (see Table 11.11.1)
•JC = package thermal resistance, Junction to case thermal resistance (C/W) (see Table 11.11.1)
•HEATSINK = cooling device thermal resistance (C/W), provided in the cooling device datasheet
•P
D = device power consumpti on (W)
•T
A is the ambient temperature (C)
Parameter Value
Addresses 0x4A
I2C specification Revision 6.0
Maximum bus speed (SCL) (1) 400 kHz
Standard mode (2) 100 kHz
Fast mode (2) 400 kHz
Note 1: The values of pull-up resistors should be chosen to ensure SCL and SDA rise and fall times meet the I2C specification.
The value required will depend on the amount of capacitance loading on the lines.
2: In systems with heavily laden I2C lines, even with minimum pull-up resistor values, bus speed may be limited by
capacitive loading to less than the theoretical maximum.
Parameter Min Typ Max Units Notes
Linearity (touch only; 5.4 mm electrode
pitch) – ±1 – mm 8 mm or greater finger
Linearity (touch only; 4.2 mm electrode
pitch) – ±0.5 – mm 4 mm or greater finger
Accuracy – ±1 – mm
Accuracy at edge – ±2 – mm
Repeatability – ±0.25 – % X axis with 12-bit resolution
Parameter Description Typ Unit Condition Package
JA Junction to ambient thermal
resistance 33.7 C/W Still air 56-pin XQFN 6 × 6 × 0.4 mm
JC Junction to case thermal resistance 10.1 C/W 56-pin XQFN 6 × 6 × 0.4 mm
TJTAPDJA
+=
TJTAPDHEATSINK JC
++=
2019 Microchip Technology Inc. DS40001922C-page 47
MXT336U 1.0
11.12 ESD Information
11.13 Soldering Profile
11.14 Moisture Sensitivity Level (MSL)
Parameter Value Referen ce standard
Human Body Model (HBM) ±2000 V JEDEC JS–001
Charge Device Model (CDM) ±250 V JEDEC JS–001
Profile Feature Green Package
Average Ramp-up Rate (217C to Peak) 3C/s max
Preheat Temperature 175C ±25C 150 – 200C
Time Maintained Above 217C 60 – 150 s
Time within 5C of Actual Peak Tempera ture 30 s
Peak Tempera ture Range 260C
Ramp down Rate 6C/s max
Time 25C to Peak Temperature 8 minutes max
MSL Rating Package Type(s) Pea k Body Temperature Specifications
MSL3 XQFN 260oC IPC/JEDEC J-STD-020
MXT336U 1.0
DS40001922C-page 48 2019 Microchip Technology Inc.
12.0 PACKAGING INFORMATION
12.1 Package Marking Information
12.1.1 56-PIN XQFN
12.1.2 ORDERABLE PART NUMBERS
The product identification system for maXTouch devices is described in “Product Iden tification System”. That section
also lists example part numbers for the mXT336U device.
Pin 1 ID
Abbreviation of
Part Number
Lot Code
(variable text)
YYWW # CC
LOTCODE
Die Revision
(variable text)
Date
(year and week) Country Code
(variable text)
MXT336U
2019 Microchip Technology Inc. DS40001922C-page 49
MXT336U 1.0
12.2 Package Details
The following section gives the technical de tails of the package for the device.
12.2.1 56-PIN XQF N 6 × 6 × 0.4 MM
MXT336U 1.0
DS40001922C-page 50 2019 Microchip Technology Inc.
APPENDIX A: ASSOCIATED DOCUMENTS
The following documents are available by contacting Microchip HMID Division:
Product Documentation
• Application Note: MXTAN0213 – Interfacing with Atmel maXTouch Controllers
Touchscreen design and PCB/FPCB layout guidelines
• Application Note: QTAN0054 – Getting Started with maXTouch Touchscreen Designs
• Application Note: MXTAN0208 – Design Guide for PCB Layouts for Atmel Touch Controllers
• Application Note: QTAN0080 – Touchscreens Sensor Design Guide
• Application Note: doc0484 – Selecting Decoupling Capacitors for Atmel PLDs
Configuring the device
• Application Note: QTAN0059 – Using the maXTouch Self Test Feature
• Application Note: MXT0202 – Using the Unlock Gesture T81 Object
Miscellaneous
• Application Note: QTAN0050 – Using the maXTouch Debug Port
• Application Note: QTAN0058 – Rejecting Unintentional Touches with the maXTouch Touchscreen Controllers
• Application Note: QTAN0061 – maXTouch Sensitivity Effects for Mobile Devices
Tools
•maXTouch Studio User Guide (distributed as on-line help with maXTouch Studio)
NOTE Some of the documents listed below are available under NDA only.
2019 Microchip Technology Inc. DS40001922C-page 51
MXT336U 1.0
APPENDIX B: REVISION HISTORY
Revision CX (December 2015)
Last released edition for firmware revision 1.0 – Atmel Release version
Revision A (June 2017)
Reformatted edition for firmware revision 1.0 – Microchip Release version
This revision incorporates the following updates:
• Updated to Microchip datasheet format:
-“Connection and Configuration Information” moved to start of datasheet
-“To Our Valued Customers” added
-Section 12.0 “Packaging Information” updated with new headings. Part numbers moved to “Product
Identification System”
- Associated Documents moved to Appendix A “Associated Documents”
- Revision History move d to this appendix
- Index added
-“Product Identification System” added
-“The Microchip Web Site”, “Customer Change Notification Service” and “Customer Support” sections added
- Back cover updated
• Features: Typical screen size updated
•“Connection and Configuration Information”:
- Update d to show power rail information
•Section 2.0 “Schematics”:
- Pull-ups are shown connected to the corre ct power rail (Vdd or VddIO)
- Section 3.3.4 RESET Line removed; Creset no longer co nsid ered optional so note no longer needed
•Section 4.0 “Sensor Layout”:
- Touch panel layout notes updated to aid clarity
-Section 4.1 “Screen Size” added
•Section 11.0 “Specifications”:
- DC characteristics updated to show rise/fall rates correctly. AVdd minimum is now 3.0 V
- I/O characteristi cs updated to show power rail information
• DBG_DAT pin renamed to DBG_DATA
• References to restricted documents removed throughout
• References to Atmel Corporation removed or changed to Microchip Technology Inc, where appropriate
• New documentation number assigned
Revision B (May 2018)
This revision incorporates the following updates:
• Features:
- Front Panel Material updated
- Touch Performance: Glove Support updated
•Section 6.0 “Detailed Operation”:
-Section 6.4 “Sensor Acquisition”: Section updated
•Section 4.0 “Sensor Layout”:
- Tables showing allowable configurations added
MXT336U 1.0
DS40001922C-page 52 2019 Microchip Technology Inc.
Revision C (April 2019)
This revision incorporates the following updates:
•Section 2.0 “Schematics”: GND symbol added to VDDCORE on schematic diagram
•Section 4.0 “Sensor Layout”: Allowable touchscreen config urations updated
•Section 11 .7 “Touchscre en Sensor Characteristics” added
2019 Microchip Technology Inc. DS40001922C-page 53
MXT336U 1.0
INDEX
A
Absolute maximum specifications...............................................38
Adjacent key suppression technology.........................................22
AKS. See Adjacent key suppression
Analog voltage supply.................................................................38
AVdd voltage supply ...................................................................38
C
Calibration...................................................................................20
Capacitive Touch Engine (CTE)....................................................8
Charge time.................................................................................20
Checksum in I2C writes...................................... ..................... ....23
CHG line
I2C.......................................................................................26
mode 0 operation................................................................27
mode 1 operation................................................................27
Clock stretching...........................................................................28
Connection Information see Pinouts .............................................3
Customer Change Notification Service .......................................56
Customer Notification Service.....................................................56
Customer Support.......................................................................56
D
DC characteristics.......................................................................38
Debugging...................................................................................37
object-based protocol..........................................................37
primary hardware interface .................................................11
secondary debug interface..................................................37
self test................................................................................37
SPI Debug Interface............................................................37
Detailed operation.......................................................................20
Detection integrator.....................................................................20
Device
overview................................................................................8
Digital filtering..............................................................................21
Digital voltage supply ..................................................................39
Direct Memory Access................................................................24
E
ESD information..........................................................................47
G
Generic key array........................................................................16
Glove detection...........................................................................22
Grip suppression.........................................................................21
I
I2C communications..............................................................23–28
CHG line..............................................................................26
clock stretching ...................................................................28
reading from the device.......................................................24
reading messages with DMA ..............................................24
SCL line...............................................................................27
SDA line..............................................................................27
specification ........................................................................46
writes in checksum mode....................................................23
writing to the device ............................................................23
I2C interface
SCL line.........................................................................10, 27
SDA line........................................................................10, 27
Input/Output characteristics ........................................................45
Internal voltage pump..................................................................10
Internet Address..........................................................................56
J
Junction temperature...................................................................46
L
Lens bending...............................................................................21
M
Microchip Internet Web Site.........................................................56
Moisture sensitivity level (msl).....................................................47
Multiple function pins...................................................................10
Mutual capacitance measurements...............................................8
N
Noise suppression.......................................................................21
display .................................................................................21
O
Object-based protocol....................... ..................... ..................... . 37
Operational modes ......................................................................20
Overview of the mXT336U.............................................................8
P
Pinouts...........................................................................................3
Power supply ripple and noise.....................................................39
Primary debug interface...............................................................11
R
Recommended operating conditions.......................................... .38
Repeatability................................................................................46
Reset timings ..............................................................................45
Retransmission compensation.....................................................21
S
SCL line.......................................................................................27
SCLline..................................................................................10, 27
Screen size..................................................................................14
SDA line.................................................................................10, 27
Secondary debug interface..........................................................37
Self capacitance measurements....................................................8
Self test........................................................................................37
Sensor acquisition .......................................................................20
Sensor layout.........................................................................13–16
Shieldless support .......................................................................21
Soldering profile...........................................................................47
Specifications.........................................................................38–47
absolute maximum specifications........................................38
analog voltage supply..........................................................38
DC characteristics ...............................................................38
digital voltage supply ...........................................................39
esd information....................................................................47
I2C specification .... .................... ..................... ..................... . 46
input/output characteristics..................................................45
junction temperature............................................................46
moisture sensitivity level (msl).............................................47
power supply ripple and noise.............................................39
recommended operating conditions ....................................38
repeatability .........................................................................46
reset timings .......................................................................45
soldering profile ...................................................................47
test configuration .................................................................40
thermal data.........................................................................46
timing specifications ............................................................44
touch accuracy ....................................................................46
touchscreen sensor characteristics.....................................45
MXT336U 1.0
DS40001922C-page 54 2019 Microchip Technology Inc.
XVdd voltage supply ...........................................................39
SPI Debug Interface....................................................................37
Standard Key arrays ...................................................................14
Stylus support .............................................................................22
T
Test configuration specification...................................................40
Thermal data...............................................................................46
Timing specifications...................................................................44
Touch accuracy...........................................................................46
Touch detection.......................................................................8, 20
Touchscreen sensor characteristics............................................45
Tuning.........................................................................................37
U
Unintentional touch suppression.................................................22
V
Vdd voltage supply......................................................................39
VddCore supply...........................................................................10
VddIO voltage supply..................................................................39
W
WWW Address............................................................................56
X
XVdd voltage supply ...................................................................39
2019 Microchip Technology Inc. DS40001922C-page 55
MXT336U 1.0
PRODUCT IDENTIFICATION SYSTEM
The table below gives details on the product identification system for maXTouch devices. See “Orderable Part
Numbers” below for example part numbers for the mXT336U device.
To order or obtain information, for example on pricing or delivery, refer to the factory or the listed sales office.
Orderable Part Numbers
Device: Base device name
Package: A
C2U
MA5U
=
=
=
QFP (Plastic Quad Flatpack)
UFBGA (Ultra Thin Fine-pitch Ball Grid Array)
QFN (Quad Flat No Lead Sawn)
Temperature Range: Blank
T
B
X
=
=
=
=
–40C to +85C (Grade 3)
–40C to +85C (Grade 3)
–40C to +105C (Grade 2)
0C to +70C (Engineering Samples)
Sample Type: Blank
ES =
=Release Sample
Pre-release (Engineering) Sample
Tape and Reel Option: Blank
R=
=Standard Packaging (Tube or Tray)
Tape and Reel (1)
Pattern: QTP, SQTP, Code or Special Requirements
(Blank Otherwise)
Note 1: Tape and Reel identifier only appears in the catalog part number description. This
identifier is used for ordering purposes and is not printed on the device package.
See “Orderable Part Numbers” below or check with your Microchip Sales Office for
package availability with the Tape and Reel option.
Orderable Part Nu mber Fi rmware Revision Description
ATMXT336U-MAU021
(Supplied in trays) 1.0.AB 56-pin XQFN 6 × 6 × 0.4 mm
RoHS compliant
Industrial grade sample; not suitable for automotive
characterization
ATMXT336U-MAUR021
(Supplied in tape and reel)
PART NO.
Device
[]X
Tape and
Reel Option
[]XX
Sample
Type
[]X
Temperature
Range
–XXX
Package
[]XXX
Pattern
MXT336U 1.0
DS40001922C-page 56 2019 Microchip Technology Inc.
THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at www.microchip.com. This web site is us ed as a means to make
files and information easily available to customers. Accessible by using your favorite Internet browser, the web site
contains the following information:
•Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s
guides and hardware support documents, latest software releases and archived software
•General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion
groups, Microchip consultant program member listing
•Business of Mic r oc hi p – Product selector and ordering guides, latest Microchip press releases, listing of
seminars and events, listings of Microchip sales offices, distributors and factory representatives
CUSTOMER CHANGE NOTIFICATION SERVICE
Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive
e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or
development tool of interest.
To register, access the Microchip web site at www.microchip.com. Under “Support”, click on “Customer Change
Notification” and follow the registration instructi ons.
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
Customers should contact their distributor, representative or Field Application Engin eer (FAE) fo r support. Local sa les
offices are also available to help customers. A listing of sales offices and locations is included in the back of this
document.
Techni cal support is available through the web site at: http://microchip.com/support
2019 Microchip Technology Inc. DS40001922C-page 57
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended
manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge,
require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely,
the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean
that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products.
Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized
access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your conve-
nience and may be superseded by updates. It is your
responsibility to ensure that your application meets with
your specifications. MICROCHIP MAKES NO REPRESEN-
TATIONS OR WARRANTIES OF ANY KIND WHETHER
EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATU-
TORY OR OTHERWISE, RELATED TO THE INFORMA-
TION, INCLUDING BUT NOT LIMITED TO ITS
CONDITION, QUALITY, PERFORMANCE, MERCHANT-
ABILITY OR FITNESS FOR PURPOSE. Microchip dis-
claims all liability arising from this information and its use.
Use of Microchip devices in life suppo rt and/or safety a ppli-
cations is entirely at the buyer’s risk, and the buyer agrees
to defend, indemni fy and hold harmless Microch ip from any
and all damages, claims, suits, or expenses resulting from
such use. No licenses are conveyed, implicitly or otherwise,
under any Microchip intellectual property rights unless oth-
erwise stated.
Trademarks
The Microchip name and logo, the Microchip logo, AnyRate, AVR,
AVR logo, AVR Freaks, BitCloud, chipKIT, chipKIT logo,
CryptoMemory, CryptoRF, dsPIC, FlashFlex, flexPWR, Heldo,
JukeBlox, KeeLoq, Kleer, LANCheck, LINK MD, maXStylus,
maXTouch, MediaLB, megaAVR, MOST, MOST logo , MPLAB,
OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo, Prochip
Designer, QTou ch, SAM-BA, SpyNIC, SST, SST Logo, SuperFlash,
tinyAVR, UNI/O, and XMEGA are registered trademarks of Microchip
Technology Incorporated in the U.S. A. and other countries.
ClockWorks, The Embedded Control Solu tions Company,
EtherSynch, Hyper Speed Control, HyperLight Load, IntelliMOS,
mT ouch, Precision Edge, and Quiet-Wire are registered trademarks of
Microchip Technology Incorporated in t he U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Ag e, Any
Capacitor, AnyIn, AnyOut, BodyCom, CodeGuard ,
CryptoAuthen tic ation, CryptoAuto motive, CryptoComp an io n,
CryptoCo nt roller, dsPICDEM, dsPICDE M .n e t, Dy namic Aver ag e
Matching, DAM, ECAN, EtherGREEN, In-Circuit Seria l Programming,
ICSP, INICnet, Inter-Chip Connectivity, JitterBlocker, KleerNet,
KleerNet logo, memBrain, Mindi, MiWi, motorBench, MPASM, MPF,
MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach,
Omniscient Code Gener ation, PICDEM, PICDEM.ne t, PICkit, PICtail,
PowerSmart, PureSilicon, QMatrix, REAL ICE, Ripple Blocker,
SAM-ICE, Serial Quad I/O, SMART-I.S., SQI, SuperSwitcher,
SuperSwitcher II, Total Endurance, TSHARC, USBCheck, V ariSense,
ViewSpan, WiperLock, Wir eless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other countries.
SQTP is a serv ice mark of Microchip Tech nology Incorporated in the
U.S.A.
Silicon Storage Technology is a registered trademark of Microchip
Technology Inc. in othe r co untries.
GestIC is a reg istered trademark of Microchip Technology Germany II
GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in other
countries.
All other trademarks mentioned herein are property of their respective
companies.
© 2017 – 2019, Microchip Technology Incorporated, All Rights
Reserved.
ISBN: 978-1-5224-4365-0
Microchip received ISO/TS-16949 :2009 certification for its worldwide head-
quarters, design and wafer fabricat ion facilities in Chandler and T empe, Ari-
zona; Gresham, Oregon and design centers in California and India. The
Company’s quality system processes and procedures are for its PIC®
MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, non vo lat ile memory and ana log p rodu cts. In
addition, Microchip’s quality system for the design and manufacture of
development systems is I SO 9001:2000 certified.
QUALITYMANAGEMENTSYSTEM
CERTIFIEDBYDNV
== ISO/TS16949==
DS40001922C-page 58 2019 Microchip Technology Inc
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Tel: 61-2-9868-6733
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Tel: 86-10-8569-7000
China - Chengdu
Tel: 86-28-8665-5511
China - Chongqing
Tel: 86-23-8980-9588
China - Dongguan
Tel: 86-769-8702-9880
China - Guangzhou
Tel: 86-20-8755-8029
China - Hangzhou
Tel: 86-571-8792-8115
China - Hong Kong SAR
Tel: 852-2943-5100
China - Nanjing
Tel: 86-25-8473-2460
China - Qingdao
Tel: 86-532-8502-7355
China - Shanghai
Tel: 86-21-3326-8000
China - Shenyang
Tel: 86-24-2334-2829
China - Shenzhen
Tel: 86-755-8864-2200
China - Suzhou
Tel: 86-186-6233-1526
China - Wuhan
Tel: 86-27-5980-5300
China - Xian
Tel: 86-29-8833-7252
China - Xiamen
Tel: 86-592-2388138
China - Zhuhai
Tel: 86-756-3210040
ASIA/PACIFIC
India - Bangalore
Tel: 91-80-3090-444 4
India - New Delhi
Tel: 91-11-4160-8631
India - Pune
Tel: 91-20-4121-014 1
Japan - Osaka
Tel: 81-6-6152-7160
Japan - Tokyo
Tel: 81-3-6880- 3770
Korea - Daegu
Tel: 82-53-744-4301
Korea - Seoul
Tel: 82-2-554-7200
Malaysia - Kuala Lumpur
Tel: 60-3-7651-7906
Malaysia - Penang
Tel: 60-4-227-8870
Philippines - Manila
Tel: 63-2-634-9065
Singapore
Tel: 65-6334-8870
Taiwan - Hsin Chu
Tel: 886-3-577-8366
Taiwan - Kaohsiung
Tel: 886-7-213-7830
Taiwan - Taipei
Tel: 886-2-2508-860 0
Thailand - Bangkok
Tel: 66-2-694-1351
Vietnam - Ho Chi Minh
Tel: 84-28-5448-210 0
EUROPE
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
Finland - Espoo
Tel: 358-9-4520-820
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-9 0-79
Germany - Garching
Tel: 49-8931-9700
Germany - Haan
Tel: 49-2129-3766400
Germany - Heilbronn
Tel: 49-7131-67-3636
Germany - Karlsruhe
Tel: 49-721-625370
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Germany - Rosenheim
Tel: 49-8031-354-560
Israel - Ra’anana
Tel: 972-9-744-7705
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Italy - Padova
Tel: 39-049-7625286
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Norway - Trondheim
Tel: 47-7289-4388
Poland - Warsaw
Tel: 48-22-3325737
Romania - Bucharest
Tel: 40-21-407-87-50
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
Sweden - Gothenberg
Tel: 46-31-704-60-40
Sweden - Stockholm
Tel: 46-8-5090-4654
UK - Wokingham
Tel: 44-118-921-5800
Fax: 44-118-921-5820
Worldwide Sales and Service
