Atmel-42223FS–SAM-R21_Summary–11/2015
SMART
Description
The Atmel® | SMART™ SAM R21 is a series of low-power microcontrollers using the 32-bit ARM®
Cortex®-M0+ processor and an integrated ultra-low power 2.4GHz ISM band transceiver. SAM
R21 devices are available in 32- and 48-pin packages with up to 256KB Flash, 32KB of SRAM
and are operating at a maximum frequency of 48MHz and reach 2.46 Coremark/MHz. They are
designed for simple and intuitive migration with identical peripheral modules, hex compatible
code, identical linear address map and pin compatible migration paths between all devices in the
product series. All devices include intelligent and flexible peripherals, Atmel Event System for
inter-peripheral signaling, and support for capacitive touch button, slider and wheel user
interfaces.
The Atmel SAM R21 devices provide the following features: In-system programmable Flash,
optional 512KB serial Flash,12-channel direct memory access (DMA) controller, 12-channel
Event System, programmable interrupt controller, up to 28 programmable I/O pins, ultra-low
power 2.4GHz ISM band transceiver with a data rate of 250kb/s, 32-bit real-time clock and
calendar, three 16-bit Timer/Counters (TC) and three 16-bit Timer/Counters for Control (TCC),
where each TC can be configured to perform frequency and waveform generation, accurate
program execution timing or input capture with time and frequency measurement of digital
signals. The TCs can operate in 8- or 16-bit mode, selected TCs can be cascaded to form a 32-bit
TC, and the three Timer/Counters for Control have extended functions optimized for motor,
lighting and other control applications. The series provide one full-speed USB 2.0 embedded host
and device interface; up to five Serial Communication Modules (SERCOM) that each can be
configured to act as an USART, UART, SPI, I2C up 3.4MHz and LIN slave; up to eight channel
350ksps 12-bit ADC with programmable gain and optional oversampling and decimation
supporting up to 16-bit resolution, two analog comparators with window mode, Peripheral Touch
Controller supporting up to 48 buttons, sliders, wheels and proximity sensing; programmable
Watchdog Timer, brown-out detector and power-on reset and two-pin Serial Wire Debug (SWD)
program and debug interface.
All devices have accurate and low-power external and internal oscillators. All oscillators can be
used as a source for the system clock. Different clock domains can be independently configured
to run at different frequencies, enabling power saving by running each peripheral at its optimal
clock frequency, and thus maintaining a high CPU frequency while reducing power consumption.
The SAM R21 devices have two software-selectable sleep modes, idle and standby. In idle mode
the CPU is stopped while all other functions can be kept running. In standby all clocks and
functions are stopped expect those selected to continue running. The device supports
SleepWalking, which is the module's ability to wake itself up and wake up its own clock, and
hence perform predefined tasks without waking up the CPU. The CPU can then be only woken on
a need basis, e.g. a threshold is crossed or a result is ready. The Event System supports
synchronous and asynchronous events, allowing peripherals to receive, react to and send events
even in standby mode.
The Flash program memory can be reprogrammed in-system through the SWD interface. The
same interface can be used for non-intrusive on-chip debug of application code. A boot loader
running in the device can use any communication interface to download and upgrade the
application program in the Flash memory.
The SAM R21 devices are supported with a full suite of program and system development tools,
including C compilers, macro assemblers, program debugger/simulators, programmers and
evaluation kits.
Atmel SAM R21E / SAM R21G
SMART ARM-Based Wireless Microcontroller
DATASHEET SUMMARY
2
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
Features
zProcessor
zARM Cortex-M0+ CPU running at up to 48MHz
zSingle-cycle hardware multiplier
zMicro Trace Buffer (MTB)
zMemories
z768(1)/256/128/64KB in-system self-programmable Flash
z32/16/8KB SRAM
zSystem
zPower-on reset (POR) and brown-out detection (BOD)
zInternal and external clock options with 48MHz Digital Frequency Locked Loop (DFLL48M) and 48MHz to 96MHz Fractional
Digital Phase Locked Loop (FDPLL96M)
zExternal Interrupt Controller (EIC)
zUp to 15 external interrupts
zOne non-maskable interrupt
zTwo-pin Serial Wire Debug (SWD) programming, test and debugging interface
zLow Power
zIdle and standby sleep modes
zSleepWalking peripherals
zPeripherals
z12-channel Direct Memory Access Controller (DMAC)
z12-channel Event System
zIntegrated Ultra Low Power Transceiver for 2.4GHz ISM Band
zSupported PSDU Data rates: 250kb/s, 500kb/s, 1000kb/s and 2000kb/s(2)
z-99dBm RX Sensitivity; TX Output Power up to +4dBm
zHardware Assisted MAC (Auto-Acknowledge, Auto-Retry)
zSFD-Detection; Spreading; De-Spreading; Framing; CRC-16 Computation
zAntenna Diversity and TX/RX Control
z128 Byte TX/RX Frame Buffer
zIntegrated 16MHz Crystal Oscillator (external crystal needed)
zPLL synthesizer with 5 MHz and 500 kHz channel spacing for 2.4GHz ISM band
zHardware Security (AES, True Random Generator)
zThree 16-bit Timer/Counters (TC), configurable as either:
zOne 16-bit TC with compare/capture channels
zOne 8-bit TC with compare/capture channels
zOne 32-bit TC with compare/capture channels, by using two TCs
zThree 16-bit Timer/Counters for Control (TCC), with extended functions:
zUp to four compare channels with optional complementary output
zGeneration of synchronized pulse width modulation (PWM) pattern across port pins
zDeterministic fault protection, fast decay and configurable dead-time between complementary output
zDithering that increase resolution with up to 5 bit and reduce quantization error
z32-bit Real Time Counter (RTC) with clock/calendar function
zWatchdog Timer (WDT)
zCRC-32 generator
zOne full-speed (12Mbps) Universal Serial Bus (USB) 2.0 interface
zEmbedded host and device function
zEight endpoints
zUp to five Serial Communication Interfaces (SERCOM), each configurable to operate as either:
zUSART with full-duplex and single-wire half-duplex configuration
zI2C up to 3.4MHz
zSPI
zLIN slave
zOne 12-bit, 350ksps Analog-to-Digital Converter (ADC) with up to eight external channels
zDifferential and single-ended input
z1/2x to 16x programmable gain stage
zAutomatic offset and gain error compensation
zOversampling and decimation in hardware to support 13-, 14-, 15- or 16-bit resolution
zTwo Analog Comparators (AC) with window compare function
zPeripheral Touch Controller (PTC)
z48-channel capacitive touch and proximity sensing
zI/O and Package
z16/28 programmable I/O pins
z32-pin and 48-pin QFN
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
zOperating Voltage
z1.8V – 3.6V
zTemperature Range
z-40°C to 85°C Industrial
z-40°C to 125°C Industrial
Notes: 1. Only applicable for SAM R21E19: 256KB embedded + 512KB serial Flash.
2. High data rates (500kb/s, 1000kb/s and 2000kb/s) only applicable for T=-40°C to 85°C.
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
1. Configuration Summary
SAM R21G SAM R21E
Pins 48 32
General Purpose I/O-pins (GPIOs) 28 16
Flash 256/128/64KB 256/128/64KB
SRAM 32/16/8KB 32/16/8KB
Timer Counter (TC) instances 3 3
Waveform output channels per TC instance 2 2
Timer Counter for Control (TCC) instances 3 3
Waveform output channels per TCC 4/4/2 4/4/2
DMA channels 12 12
USB interface 1 1
Serial Communication Interface (SERCOM) instances 5+1(1) 4+1(1)
Inter-IC Sound (I2S) interface No No
Analog-to-Digital Converter (ADC) channels 8 4
Analog Comparators (AC) 2 2
Digital-to-Analog Converter (DAC)
channels No No
Real-Time Counter (RTC) Yes Yes
RTC alarms 1 1
RTC compare values 1 32-bit value or
2 16-bit values
1 32-bit value or
2 16-bit values
External Interrupt lines 15 14
Peripheral Touch Controller (PTC) X and Y lines 8x6 6x2
Maximum CPU frequency 48MHz
Packages QFN QFN
32.768kHz crystal oscillator (XOSC32K) Yes No
Oscillators
16MHz crystal oscillator for 2.4GHz TRX (XOSCRF)
0.4-32MHz crystal oscillator (XOSC)
32.768kHz internal oscillator (OSC32K)
32kHz ultra-low-power internal oscillator (OSCULP32K)
8MHz high-accuracy internal oscillator (OSC8M)
48MHz Digital Frequency Locked Loop (DFLL48M)
96MHz Fractional Digital Phased Locked Loop (FDPLL96M)
Event System channels 12 12
SW Debug Interface Yes Yes
Watchdog Timer (WDT) Yes Yes
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
Note: 1. SERCOM4 is internally connected to the AT86RF233.
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
2. Ordering Information
2.1 SAM R21E
Note: 1. Serial Flash MX25V4006EWSK. For more information, see http://www.macronix.com.
ATSAMR 21 E 16 A - M U T
Product Family
SAMR = SoC Microcontroller with RF
Product Series
21 = Cortex M0+ CPU, USB
Flash Memory
19 = 256KB + 512KB
18 = 256KB
17 = 128KB
16 = 64KB
Device Variant
A = Default Variant
Pin Count
E = 32 Pins
G = 48 Pins
Package Carrier
No character = Tray (Default)
T = Tape and Reel
Package Grade
Package Type
M = QFN
U = -40 - 85°C Matte Sn Plating
F = -40 - 125°C Matte Sn Plating
Ordering Code FLASH (bytes) SRAM (bytes) Package Carrier Type
ATSAMR21E16A-MF
64K 8K QFN32
Tray
ATSAMR21E16A-MFT Tape & R ee l
ATSAMR21E16A-MU Tray
ATSAMR21E16A-MUT Tape & R ee l
ATSAMR21E17A-MF
128K 16K QFN32
Tray
ATSAMR21E17A-MFT Tape & R ee l
ATSAMR21E17A-MU Tray
ATSAMR21E17A-MUT Tape & R ee l
ATSAMR21E18A-MF
256K 32K QFN32
Tray
ATSAMR21E18A-MFT Tape & R ee l
ATSAMR21E18A-MU Tray
ATSAMR21E18A-MUT Tape & R ee l
ATSAMR21E19A-MF
256K + 512K(1) 32K QFN32
Tray
ATSAMR21E19A-MFT Tape & R ee l
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
2.2 SAM R21G
Ordering Code FLASH (bytes) SRAM (bytes) Package Carrier Type
ATSAMR21G16A-MF
64K 8K QFN48
Tray
ATSAMR21G16A-MFT Tape & R e el
ATSAMR21G16A-MU Tray
ATSAMR21G16A-MUT Tape & Re el
ATSAMR21G17A-MF
128K 16K QFN48
Tray
ATSAMR21G17A-MFT Tape & R e el
ATSAMR21G17A-MU Tray
ATSAMR21G17A-MUT Tape & Re el
ATSAMR21G18A-MF
256K 32K QFN48
Tray
ATSAMR21G18A-MFT Tape & R e el
ATSAMR21G18A-MU Tray
ATSAMR21G18A-MUT Tape & Re el
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
3. Block Diagrams
3.1 MCU Block Diagram
Notes: 1. Some products have different number of SERCOM instances, Timer/Counter instances, PTC signals and ADC sig-
nals. Refer to “Ordering Information” on page 6 for details.
2. The three TCC instances have different configurations, including the number of Waveform Output (WO) lines.
3. Refer to the PORT Function Multiplexing Table 5-1 for details about the available GCLK_IO and ADC signals.
4. Only available for SAM R21G.
6 x SERCOM
8 x Timer Counter
REAL TIME
COUNTER
AHB-APB
BRIDGE C
M
M
HIGH SPEED
BUS MATRIX
PORT
PORT
WATCHDOG
TIMER
SERIAL
WIRE
SWDIO
S
CORTEX-M0+
PROCESSOR
Fmax 48 MHz
SWCLK
DEVICE
SERVICE
UNIT
AHB-APB
BRIDGE A
8-CHANNEL
12-bit ADC 350KSPS
AIN[n]
AIN[3..0]
S
SRAM
CONTROLLER
32/16/8KB
RAM
M
RESET
CONTROLLER
SLEEP
CONTROLLER
CLOCK
CONTROLLER
POWER MANAGER
RESETN
3 x TIMER / COUNTER
EVENT SYSTEM
S
5x SERCOM
2 ANALOG
COMPARATORS
SYSTEM CONTROLLER
OSCULP32K
OSC32K
OSC8M
DFLL48M
BOD33
VREF
X[7..0]
Y[5..0]
PERIPHERAL
TOUCH
CONTROLLER
PERIPHERAL
ACCESS CONTROLLER
AHB-APB
BRIDGE B
EXTERNAL INTERRUPT
CONTROLLER
PERIPHERAL
ACCESS CONTROLLER
PERIPHERAL
ACCESS CONTROLLER
EXTINT[15..1]
NMI
GCLK_IO[n]
S
XOUT
XIN
XOUT32
XIN32
XOSC32K
XOSC
PAD0
WO1
PAD1
PAD2
PAD3
WO0
VREFB
256/128/64KB
NVM
NVM
CONTROLLER
Cache
S
DMA
USB FS
DEVICE
MINI-HOST
DP
DM
3x TIMER / COUNTER
FOR CONTROL
WOn
IOBUS
FDPLL96M
DMA
DMA
DMA
DMA
MEMORY
TRACE BUFFER
S
SOF 1KHZ
WO0
WO1
(2)
(3)
(3) GENERIC CLOCK
CONTROLLER
(4)
9
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
3.2 SAM R21 Interconnection
SAMR21
AT86RF233
SAMD21
SPI
(Slave)
SERCOM 4(3)
XOSC
RF
/SEL
MISO
MOSI
SCLK
AVREG
2.4GHz TRX (analog)
DIG3
AVSS
AVSS
XTAL1
XTAL2
EXTERNAL
INTERRUPT
CONTROLLER
IRQ
Control Logic
GENERIC
CLOCK
CLKM
AVSS
ADC
DVREG
DVSS
DVDD
DEVDD
RFP
RFN
PC16
PB00
PC18
PC19
PB30
PB31
TRX (digital)
PORT
SLP_TR
RSTN
DIG2
DIG1
DIG4
2.4 GHz RF
front-end circuit
FECTRL0..1
AC
XOSC
32K
VREG
DVDD
GNDANA
RFN
RFP
AVSS GNDANA
XTAL1
XTAL2
GNDANA
VDDIO
AVDD
AVDD
EVDD
VDDANA
GNDANA
PAD3
PAD0
PAD2
PAD1
VDDIN
VDDCORE
GND
EXTINT0
GCLK_IO1
(4)
PTC
PA09
PA08
PA13
(2)
PA12
(2)
PA14
PA15
FECTRL2..5
(1)
Notes: 1. Paddle connected to digital ground DVSS, GND.
2. Only available for SAM R21G.
3. Dedicated SERCOM4 alternate pin function mapping for internally connected AT86RF233.
4. Die revision A uses GCLK_IO5.
5. Only available for SAM R21E19.
RFCTRL
DIG1..4
SERCOM 5
PAD3
PAD0
PAD2
PAD1
PA20
PB15
MX25V4006(5)
(1)
PB23
PA22
PB22
PA23
SI
CS#
SCLK
SO
PORT
GND PA12
WP#
PA00
HOLD#VCC
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
4. Pinout
4.1 SAM R21G - QFN48
Note: The large center pad underneath the QFN package is made of metal and internally connected to GND.
It should be soldered and connected to the digital ground on the board to ensure good mechanical stability.
It is not recommended to use the exposed paddle as a replacement of the regular GND pin.
GND
VDDIO 13
GND 14
PA08 15
PA09 16
GNDANA 17
RFP 18
RFN 19
GNDANA 20
PA12 21
PA13 22
PA14 23
PA15 24
PA1625
PA1726
PA1827
PA1928
GND29
DVDD30
PA2231
PA2332
PA2433
PA2534
GND35
VDDIO36
PB0348
PB0247
PA3146
PA3045
VDDIN44
VDDCORE43
42
PA2841
RESET40
PA2739
PB2338
PB2237
PA00 1
PA01 2
XTAL2 3
XTAL1 4
GNDANA 5
VDDANA 6
AVDD 7
GNDANA 8
PA04 9
PA05 10
PA06 11
PA07 12
DIGITAL PIN
ANALOG PIN
OSCILLATOR
GROUND
INPUT SUPPLY
REGULATED OUTPUT SUPPLY
RESET PIN
RF PIN
DIGITAL PIN/
OSCILLATOR
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
4.2 SAM R21E - QFN32
Note: The large center pad underneath the QFN package is made of metal and internally connected to GND.
It should be soldered and connected to the digital ground on the board to ensure good mechanical stability.
It is not recommended to use the exposed paddle as a replacement of the regular GND pin.
PA08
PA09
GNDANA
RFP
RFN
GNDANA
PA14
PA15
PA1617
PA1718
PA1819
PA1920
DVDD21
PA2422
PA2523
VDDIO24
PA3132
PA3031
VDDIN30
VDDCORE29
GND28
PA2827
RESET26
PA2725
XTAL2 1
XTAL1 2
GNDANA 3
VDDANA 4
AVDD 5
GNDANA 6
PA06 7
PA07 8
DIGITAL PIN
ANALOG PIN
OSCILLATOR
GROUND
INPUT SUPPLY
REGULATED OUTPUT
RESET PIN
9
10
11
12
13
14
15
16
RF PIN
DIGITAL PIN/
SUPPLY OSCILLATOR
12
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
5. I/O Multiplexing and Considerations
5.1 Multiplexed Signals
Each pin is by default controlled by the PORT as a general purpose I/O and alternatively it can be assigned to one of the
peripheral functions A, B, C, D, E, F, G or H. To enable a peripheral function on a pin, the Peripheral Multiplexer Enable
bit in the Pin Configuration register corresponding to that pin (PINCFGn.PMUXEN, n = 0..31) in the PORT must be
written to one. The selection of peripheral function A to H is done by writing to the Peripheral Multiplexing Odd and Even
bits in the Peripheral Multiplexing register (PMUXn.PMUXE/O) in the PORT.
Table 5-1 describes the peripheral signals multiplexed to the PORT I/O pins.
Table 5-1. PORT Function Multiplexing
Pin
I/O Pin Supply Type
A B(1)(2) C D E F G H
SAMR21
E
SAMR21
GEIC REF ADC AC PTC
SERCOM
(1)(2)
SERCOM-
ALT
TC
TCC
FECTRL
TCC
SERCOM COM
AC/
GCLK
1PA00 VDDANA SERCOM1/
PAD[0] TCC2/WO[0]
2PA01 VDDANA EXTINT[1] SERCOM1/
PAD[1] TCC2/WO[1]
9PA04 VDDANA EXTINT[4]
ADC/
VREFB
AIN[4] AIN[0] Y[2] SERCOM0/
PAD[0] TCC0/WO[0]
10 PA05 VDDANA EXTINT[5] AIN[5] AIN[1] Y[3] SERCOM0/
PAD[1] TCC0/WO[1]
711 PA06 VDDANA EXTINT[6] AIN[6] AIN[2] Y[4] SERCOM0/
PAD[2] TCC1/WO[0]
812 PA07 VDDANA EXTINT[7] AIN[7] AIN[3] Y[5] SERCOM0/
PAD[3] TCC1/WO[1]
915 PA08 VDDIO I2CNMI AIN[16] X[0] SERCOM0/
PAD[0]
SERCOM2/
PAD[0] TCC0/WO[0] FECTRL[0]
10 16 PA09 VDDIO I2CEXTINT[9] AIN[17] X[1] SERCOM0/
PAD[1]
SERCOM2/
PAD[1] TCC0/WO[1] FECTRL[1]
21 PA12 VDDIO I2CEXTINT[12] SERCOM2/
PAD[0] TCC2/WO[0] FECTRL[2] AC/
CMP[0]
22 PA13 VDDIO I2CEXTINT[13] SERCOM2/
PAD[1] TCC2/WO[1] FECTRL[3] AC/
CMP[1]
15 23 PA14 VDDIO EXTINT[14] SERCOM2/
PAD[2] TC3/WO[0] FECTRL[4] GCLK_IO[0]
16 24 PA15 VDDIO EXTINT[15] SERCOM2/
PAD[3] TC3/WO[1] FECTRL[5] GCLK_IO[1]
17 25 PA16 VDDIO I2CX[4] SERCOM1/
PAD[0]
SERCOM3/
PAD[0] TCC2/WO[0] TCC0/
WO[0] GCLK_IO[2]
18 26 PA17 VDDIO I2CEXTINT[1] X[5] SERCOM1/
PAD[1]
SERCOM3/
PAD[1] TCC2/WO[1] TCC0/
WO[1] GCLK_IO[3]
19 27 PA18 VDDIO EXTINT[2] X[6] SERCOM1/
PAD[2]
SERCOM3/
PAD[2] TC3/WO[0] TCC0/
WO[2]
AC/
CMP[0]
20 28 PA19 VDDIO EXTINT[3] X[7] SERCOM1/
PAD[3]
SERCOM3/
PAD[3] TC3/WO[1] TCC0/
WO[3]
AC/
CMP[1]
31 PA22 VDDIO I2CEXTINT[6] X[10] SERCOM3/
PAD[0]
SERCOM5/
PAD[0] TC4/WO[0] TCC0/
WO[4] GCLK_IO[6]
32 PA23 VDDIO I2CEXTINT[7] X[11] SERCOM3/
PAD[1]
SERCOM5/
PAD[1] TC4/WO[1] TCC0/
WO[5]
USB/
SOF1kHz GCLK_IO[7]
22 33 PA24 VDDIO EXTINT[12] SERCOM3/
PAD[2]
SERCOM5/
PAD[2] TC5/WO[0] TCC1/
WO[2] USB_DM
23 34 PA25 VDDIO EXTINT[13] SERCOM3/
PAD[3]
SERCOM5/
PAD[3] TC5/WO[1] TCC1/
WO[3] USB_DP
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
Notes: 1. All analog pin functions are on peripheral function B. Peripheral function B must be selected to disable the digital control of the pin.
2. Only some pins can be used in SERCOM I2C mode. See the Type column for using a SERCOM pin in I2C mode.
5.2 Internal Multiplexed Signals
PA20, PB00, PB15, PB30, PB31, PC16, PC18 and PC19 are by default controlled by the PORT as a general purpose I/O
and alternatively it can be assigned to one of the peripheral functions A, B, C, D, E, F, G or H. To enable a peripheral
function on a pin, the Peripheral Multiplexer Enable bit in the Pin Configuration register corresponding to that pin
(PINCFGn.PMUXEN, n = 0-31) in the PORT must be written to one. The selection of peripheral function A to H is done
by writing to the Peripheral Multiplexing Odd and Even bits in the Peripheral Multiplexing register (PMUXn.PMUXE/O) in
the PORT.
PA10, PA11, PB16 and PB17 cannot be configured as output ports. These ports are always connected to the RFCTRL
inputs.
37 PB22 VDDIO EXTINT[6] SERCOM5/
PAD[2] GCLK_IO[0]
38 PB23 VDDIO EXTINT[7] SERCOM5/
PAD[3] GCLK_IO[1]
25 39 PA27 VDDIO EXTINT[15] SERCOM3/
PAD[0] GCLK_IO[0]
27 41 PA28 VDDIO EXTINT[8] SERCOM3/
PAD[1] GCLK_IO[0]
31 45 PA30 VDDIO EXTINT[10] SERCOM1/
PAD[2] TCC1/WO[0] SWCLK GCLK_IO[0]
32 46 PA31 VDDIO EXTINT[11] SERCOM1/
PAD[3] TCC1/WO[1]
47 PB02 VDDANA EXTINT[2] AIN[10] Y[8] SERCOM5/
PAD[0]
48 PB03 VDDANA EXTINT[3] AIN[11] Y[9] SERCOM5/
PAD[1]
Table 5-1. PORT Function Multiplexing (Continued)
Pin
I/O Pin Supply Type
A B(1)(2) C D E F G H
SAMR21
E
SAMR21
GEIC REF ADC AC PTC
SERCOM
(1)(2)
SERCOM-
ALT
TC
TCC
FECTRL
TCC
SERCOM COM
AC/
GCLK
Internal
Signal I/O Pin Supply Type
A B C D E F G H
EIC REF ADC AC PTC SERCOM
SERCOM-
ALT TC
FECTRL
TCC
SERCOM COM
AC/
GCLK
DIG3 PA10 VDDIO Input EXTINT[10]
DIG4 PA11 VDDIO Input EXTINT[11]
SLP_TR PA20 VDDIO I/O
IRQ PB00 VDDANA I/O EXTINT[0]
RSTN PB15 VDDIO I/O
DIG1 PB16 VDDIO Input EXTINT[0]
DIG2 PB17 VDDIO Input EXTINT[1]
MOSI PB30 VDDIO I/O SERCOM4/
PAD[2]
SEL PB31 VDDIO I/O SERCOM4/
PAD[1]
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Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
Note: 1. Die revision A uses GCLK/IO[5].
5.3 Other Functions
5.3.1 Oscillator Pinout
The oscillators are not mapped to the normal PORT functions and their multiplexing are controlled by registers in the
System Controller (SYSCTRL).
The integrated AT86RF233 16 MHz crystal oscillator is directly connected to pins and has no multiplexing functionality.
5.3.2 Serial Wire Debug Interface Pinout
Only the SWCLK pin is mapped to the normal PORT functions. A debugger cold-plugging or hot-plugging detection will
automatically switch the SWDIO port to the SWDIO function.
CLKM PC16 VDDIO I/O GCLK/
IO[1](1)
SCLK PC18 VDDIO I/O SERCOM4/
PAD[3]
MISO PC19 VDDIO I/O SERCOM4/
PAD[0]
Internal
Signal I/O Pin Supply Type
A B C D E F G H
EIC REF ADC AC PTC SERCOM
SERCOM-
ALT TC
FECTRL
TCC
SERCOM COM
AC/
GCLK
Oscillator Supply Signal I/O Pin
XOSC VDDIO
XIN PA14
XOUT PA15
XOSC32K VDDANA
XIN32 PA00
XOUT32 PA01
Oscillator Supply Signal I/O Pin
XOSCRF EVDD/VDDANA
XTAL1 XTAL1
XTAL2 XTAL2
Signal Supply I/O Pin
SWCLK VDDIO PA30
SWDIO VDDIO PA31
15
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
6. Product Mapping
Figure 6-1. Atmel | SMART SAM R21 Product Mapping
This figure represents the full configuration of the Atmel | SMART SAM R21 with maximum Flash and SRAM capabilities and a full
set of peripherals. Refer to the “Configuration Summary” on page 4 for details.
Code
SRAM
Undefined
Peripherals
Reserved
Undefined
Reserved
Global Memory Space
0x00000000
0x20000000
0x22008000
0x40000000
0x43000000
0x60000000
0x60000200
0xFFFFFFFF
Internal SRAM
SRAM
AHB-APB
Bridge A
AHB-APB
Bridge B
AHB-APB
Bridge C
AHB-APB
Internal Flash
Reserved
Code
0x00000000
0x00400000
0x1FFFFFFF
0x20000000
0x20008000
0x40000000
0x41000000
0x42000000
0x42FFFFFF
Reserved
PAC0
PM
SYSCTRL
GCLK
WDT
RTC
EIC
AHB-APB Bridge A
0x40000000
0x40000400
0x40000800
0x40000C00
0x40001000
0x40001400
0x40001800
0x40FFFFFF
0x40001C00
AHB-APB Bridge B
Reserved
PAC1
DSU
NVMCTRL
PORT
0x41000000
0x41002000
0x41004000
0x41004400
0x41FFFFFF
0x41004700
SERCOM5
PAC2
EVSYS
SERCOM0
SERCOM1
SERCOM2
SERCOM3
SERCOM4(1)
AHB-APB Bridge C
Reserved
TCC0
TCC1
TCC2
TC3
TC4
TC5
Reserved
ADC
AC
0x42000000
0x42000400
0x42000800
0x42000C00
0x42001000
0x42001400
0x42001800
0x42002000
0x42001C00
0x42003000
0x42003400
0x42003800
0x42003C00
0x42004000
0x42004400
0x42004800
Reserved
0x40FFFFFF
Reserved
0x42004C00
0x42002400
0x42002800
0x42002C00
PTC
0x42005400
0x42005000
Reserved
RFCTRL
0x42005800
DMAC
USB
MTB
0x41004800
0x41005000
0x41006000
Note 1. SERCOM4 is internally connected to the AT86RF233.
16
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
7. Processor And Architecture
7.1 Cortex M0+ Processor
The Atmel | SMART SAM R21 implements the ARM® Cortex™-M0+ processor, which is based on the ARMv6
Architecture and Thumb®-2 ISA. The Cortex M0+ is 100% instruction set compatible with its predecessor, the Cortex-M0
processor, and upward compatible to Cortex-M3 and M4 processors.
For more information refer to www.arm.com.
7.1.1 Cortex M0+ Configuration
Note: 1. All software run in privileged mode only
The ARM Cortex-M0+ core has two bus interfaces:
zSingle 32-bit AMBA®-3 AHB-Lite™ system interface that provides connections to peripherals and all system
memory, including flash and RAM
zSingle 32-bit I/O port bus interfacing to the PORT with one-cycle loads and stores
Features Configuration option
Atmel | SMART SAM R21
configuration
Interrupts External interrupts 0-32 32
Data endianness Little-endian or big-endian Little-endian
SysTick timer Present or absent Present
Number of watchpoint comparators 0, 1, 2 2
Number of breakpoint comparators 0, 1, 2, 3, 4 4
Halting debug support Present or absent Present
Multiplier Fast or small Fast (single cycle)
Single-cycle I/O port Present or absent Present
Wake-up interrupt controller Supported or not supported Not supported
Vector Table Offset Register Present or absent Present
Unprivileged/Privileged support Present or absent Absent(1)
Memory Protection Unit Not present or 8-region Not present
Reset all registers Present or absent Absent
Instruction fetch width 16-bit only or mostly 32-bit 32-bit
17
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
8. Packaging Information
8.1 Thermal Considerations
8.1.1 Thermal Resistance Data
Table 8-1 summarizes the thermal resistance data depending on the package.
Table 8-1. Thermal Resistance Data
8.1.2 Junction Temperature
The average chip-junction temperature, TJ, in °C can be obtained from the following:
where:
zθJA = package thermal resistance, Junction-to-ambient (°C/W), provided in Table 8-1.
zθJC = package thermal resistance, Junction-to-case thermal resistance (°C/W), provided in Table 8-1.
zθHEATSINK = cooling device thermal resistance (°C/W), provided in the device datasheet.
zPD = device power consumption (W).
zTA = ambient temperature (°C).
From the first equation, the user can derive the estimated lifetime of the chip and decide if a cooling device is necessary
or not. If a cooling device is to be fitted on the chip, the second equation should be used to compute the resulting average
chip-junction temperature TJ in °C.
Package Type θJA θJC
32-pin QFN 37.2 °C/W 3.1 °C/W
48-pin QFN 33 °C/W 11.4 °C/W
18
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
8.2 Package Drawings
8.2.1 48-pin QFN
Table 8-2. Device and Package Maximum Weight
100 mg
Table 8-3. Package Characteristics
Moisture Sensitivity Level MSL3
Table 8-4. Package Reference
JEDEC Drawing Reference MO-220
JESD97 Classification E3
19
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
8.2.2 32-pin QFN (PG)
GPC:ZKV
Table 8-5. Device and Package Maximum Weight
90 mg
Table 8-6. Package Characteristics
Moisture Sensitivity Level MSL3
Table 8-7. Package Reference
JEDEC Drawing Reference MO-220
JESD97 Classification E3
20
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
8.2.3 32-pin QFN (32M5)
GPC: ZSA
Table 8-8. Device and Package Maximum Weight
78.5 mg
Table 8-9. Package Characteristics
Moisture Sensitivity Level MSL3
Table 8-10. Package Reference
JEDEC Drawing Reference MO-220
JESD97 Classification E3
21
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
9. Soldering Profile
The following table gives the recommended soldering profile from J-STD-20.
A maximum of three reflow passes is allowed per component.
SVNREVISION
Profile Feature Green Package
Average Ramp-up Rate (217°C to peak) 3°C/s max
Preheat Temperature 175°C +/-25°C 150-200°C
Time Maintained Above 217°C 60-150s
Time within 5°C of Actual Peak Temperature 30s
Peak Temperature Range 260°C
Ramp-down Rate 6°C/s max
Time 25°C to Peak Temperature 8 minutes max
22
Atmel | SMART SAM R21 [DATASHEET SUMMARY]
Atmel-42223FS–SAM-R21_Summary–11/2015
Table of Contents
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1. Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.1 SAM R21E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 SAM R21G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 MCU Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 SAM R21 Interconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4.1 SAM R21G - QFN48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 SAM R21E - QFN32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. I/O Multiplexing and Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1 Multiplexed Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2 Internal Multiplexed Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Other Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6. Product Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7. Processor And Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1 Cortex M0+ Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8. Packaging Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1 Thermal Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2 Package Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9. Soldering Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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