Atmel-46001A-SE-M90E25-Datasheet_041814
FEATURES
Metering Features
Metering features fully in compliance with the requirements of IEC62052-11 and
IEC62053-21; applicable in class 1 or class 2 single-phase watt-hour meter.
Accuracy of 0.1% for active energy over a dynamic range of 5000:1.
Temperature coefficient is 15 ppm/ (typical) for on-chip reference voltage
Single-point calibration over a dynamic range of 5000:1 for active energy.
Energy Meter Constant doubling at low current to save verification time.
Electrical parameters measurement: less than ±0.5% fiducial error for Vrms, Irms,
mean active/ apparent power, frequency, power factor and phase angle.
Forward/ reverse active energy with independent energy registers. Active energy
can be output by pulse or read through energy registers to adapt to different appli-
cations.
Programmable startup and no-load power threshold.
Dedicated ADC and different gains for L line and N line current sampling circuits.
Current sampled over shunt resistor or current transformer (CT); voltage sampled
over resistor divider network or potential transformer (PT).
Programmable L line and N line metering modes: anti-tampering mode (larger
power), L line mode (fixed L line), L+N mode (applicable for single-phase three-wire
system) and flexible mode (configure through register).
Programmable L line and N line power difference threshold in anti-tampering mode.
Other Features
3.3V single power supply. Operating voltage range: 2.8~3.6V. Metering accuracy
guaranteed within 3.0V~3.6V. 5V compatible for digital input.
Built-in hysteresis for power-on reset.
Four-wire SPI interface or simplified three-wire SPI interface with fixed 24 cycles for
all registers operation
Parameter diagnosis function and programmable interrupt output of the IRQ inter-
rupt signal and the WarnOut signal.
Programmable voltage sag detection and zero-crossing output.
Channel input range
-Voltage channel (when gain is '1'): 120μVrms~600mVrms.
-L line current channel (when gain is '24'): 5μVrms~25mVrms.
-N line current channel (when gain is '1'): 120
μ
Vrms~600mVrms.
Programmable L line current gain: 1, 4, 8, 16, 24; Programmable N line gain: 1, 2, 4.
Support L line and N line offset compensation.
CF1 outputs active energy pulses which can be used for calibration or energy accu-
mulation.
Crystal oscillator frequency: 8.192 MHz. On-chip 10pF capacitors and no need of
external capacitors.
Green SSOP28 package.
Operating temperature: -40 ~ +85 .
Atmel M90E25
Single-Phase High-Performance Wide-Span Energy
Metering IC
PRELIMINARY DATASHEET
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M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
APPLICATION
The M90E25 is used for active energy metering for single-phase two-wire (1P2W), single-phase three-wire (1P3W)
or anti-tampering energy meters. With the measurement function, the M90E25 can also be used in power instru-
ments which need to measure voltage, current, etc.
DESCRIPTION
The M90E25 is high-performance wide-span energy metering chips. The ADC and DSP technology ensure the chips'
long-term stability over variations in grid and ambient environmental conditions.
BLOCK DIAGRAM
Figure-1 Block Diagram
Reference Voltage
Power On Reset
Crystal Oscillator 3-wire or 4-wire SPI
Vref
I1P
I1N
VP
VN
L Line Forward/Reverse Active Power
L Line Apparent Power
L Line Irms
Vrms
I2P
I2N
MMD1 MMD0
CS SCLK SDO SDI
OSCI OSCO
RESET
∑△ADC
∑△ADC
HPF1 HPF0
DSP Module
PGA
X1/X4/X8/
X16/X24
PGA
X1
∑△ADC
PGA
X1/X2/X4
Active Energy
Pulse Output
CF1
HPF1 HPF0
HPF1 HPF0
N Line Forward/Reverse Active Power
N Line Apparent Power
N Line Irms
Power Factor/
Angle/Frequency
WarnOut/IRQ/ZX
ZX
IRQWarnOut
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M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
FEATURES .......................................................................................................................................... 1
APPLICATION ..................................................................................................................................... 2
DESCRIPTION ..................................................................................................................................... 2
BLOCK DIAGRAM............................................................................................................................... 2
1 PIN ASSIGNMENT .......................................................................................................................... 7
2 PIN DESCRIPTION .......................................................................................................................... 8
3 FUNCTIONAL DESCRIPTION ...................................................................................................... 10
3.1 DYNAMIC METERING RANGE .............................................................................................................................10
3.2 STARTUP AND NO-LOAD POWER .....................................................................................................................10
3.3 ENERGY REGISTERS ...........................................................................................................................................10
3.4 N LINE METERING AND ANTI-TAMPERING .......................................................................................................11
3.4.1 Metering Mode and L/N Line Current Sampling Gain Configuration ................................................... 11
3.4.2 Anti-Tampering Mode ............................................................................................................................... 11
3.5 MEASUREMENT AND ZERO-CROSSING ...........................................................................................................12
3.5.1 Measurement ............................................................................................................................................. 12
3.5.2 Zero-Crossing ............................................................................................................................................ 12
3.6 CALIBRATION .......................................................................................................................................................13
3.7 RESET ....................................................................................................................................................................14
4 INTERFACE ................................................................................................................................... 15
4.1 SERIAL PERIPHERAL INTERFACE (SPI) ...........................................................................................................15
4.1.1 Four-Wire Mode ......................................................................................................................................... 15
4.1.2 Three-Wire Mode ....................................................................................................................................... 16
4.1.3 Timeout and Protection ............................................................................................................................ 17
4.2 WARNOUT PIN FOR FATAL ERROR WARNING ................................................................................................18
4.3 LOW COST IMPLEMENTATION IN ISOLATION WITH MCU ..............................................................................18
5 REGISTER ..................................................................................................................................... 19
5.1 REGISTER LIST ....................................................................................................................................................19
5.2 STATUS AND SPECIAL REGISTER ....................................................................................................................21
5.3 METERING/ MEASUREMENT CALIBRATION AND CONFIGURATION ............................................................25
5.3.1 Metering Calibration and Configuration Register .................................................................................. 25
5.3.2 Measurement Calibration Register .......................................................................................................... 32
5.4 ENERGY REGISTER .............................................................................................................................................37
5.5 MEASUREMENT REGISTER ................................................................................................................................40
6 ELECTRICAL SPECIFICATION .................................................................................................... 46
6.1 ELECTRICAL SPECIFICATION ............................................................................................................................46
6.2 SPI INTERFACE TIMING .......................................................................................................................................48
6.3 POWER ON RESET TIMING .................................................................................................................................50
6.4 ZERO-CROSSING TIMING ....................................................................................................................................51
Table of Contents
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6.5 VOLTAGE SAG TIMING ........................................................................................................................................52
6.6 PULSE OUTPUT ....................................................................................................................................................53
6.7 ABSOLUTE MAXIMUM RATING ..........................................................................................................................53
ORDERING INFORMATION .............................................................................................................. 54
PACKAGE DIMENSIONS .................................................................................................................. 55
REVISION HISTORY ......................................................................................................................... 56
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Table-1 Pin Description ....................................................................................................................................................... 8
Table-2 Active Energy Metering Error ............................................................................................................................... 10
Table-3 Threshold Configuration for Startup and No-Load Power .................................................................................... 10
Table-4 Energy Registers .................................................................................................................................................. 10
Table-5 Metering Mode ..................................................................................................................................................... 11
Table-6 The Measurement Format .................................................................................................................................... 12
Table-7 Read / Write Result in Four-Wire Mode ............................................................................................................... 17
Table-8 Read / Write Result in Three-Wire Mode ............................................................................................................. 17
Table-9 Register List ......................................................................................................................................................... 19
Table-10 SPI Timing Specification .................................................................................................................................... 49
Table-11 Power On Reset Specification ............................................................................................................................ 50
Table-12 Zero-Crossing Specification ............................................................................................................................... 51
Table-13 Voltage Sag Specification .................................................................................................................................. 52
List of Tables
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Figure-1 Block Diagram ...................................................................................................................................................... 2
Figure-2 Pin Assignment (Top View) ................................................................................................................................... 7
Figure-3 Read Sequence in Four-Wire Mode .................................................................................................................... 15
Figure-4 Write Sequence in Four-Wire Mode .................................................................................................................... 15
Figure-5 Read Sequence in Three-Wire Mode .................................................................................................................. 16
Figure-6 Write Sequence in Three-Wire Mode .................................................................................................................. 16
Figure-7 4-Wire SPI Timing Diagram ................................................................................................................................ 48
Figure-8 3-Wire SPI Timing Diagram ................................................................................................................................ 48
Figure-9 Power On Reset Timing Diagram ....................................................................................................................... 50
Figure-10 Zero-Crossing Timing Diagram ......................................................................................................................... 51
Figure-11 Voltage Sag Timing Diagram ............................................................................................................................ 52
Figure-12 Output Pulse Width ........................................................................................................................................... 53
List of Figures
M90E25 [Preliminary Datasheet]
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1 PIN ASSIGNMENT
Figure-2 Pin Assignment (Top View)
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15
16
17
18
19
20
21
22
23
24
25
26
27
28
Reset
DVDD
AVDD
AGND
I1P
I1N
I2P
I2N
VP
VN
Vref
AGND
NC
WarnOut
CS
SCLK
SDO
SDIDGND
MMD1 MMD0
OSCI
OSCO
NC
CF1
NC
ZX
IRQ
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M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
2 PIN DESCRIPTION
Table-1 Pin Description
Name Pin No. I/O
note 1
Type Description
Reset 4ILVTTL
Reset: Reset Pin (active low)
This pin should connect to ground through a 0.1μF filter capacitor. In appli-
cation it can also directly connect to one output pin from microcontroller
(MCU).
DVDD 3 I Power
DVDD: Digital Power Supply
This pin provides power supply to the digital part. It should be decoupled
with a 10μF electrolytic capacitor and a 0.1μF capacitor.
DGND 2 I Power DGND: Digital Ground
AVDD 5 I Power
AVDD: Analog Power Supply
This pin provides power supply to the analog part. This pin should connect
to DVDD through a 10Ω resistor and be decoupled with a 0.1μF capacitor.
Vref 13 O Analog Vref: Output Pin for Reference Voltage
This pin should be decoupled with a 1μF capacitor and a 1nF capacitor.
AGND 6, 14 I Power AGND: Analog Ground
I1P
I1N
10
11 I Analog
I1P: Positive Input for L Line Current
I1N: Negative Input for L Line Current
These pins are differential inputs for L line current. Input range is
5μVrms~25mVrms when gain is '24'.
I2P
I2N
7
8I Analog
I2P: Positive Input for N Line Current
I2N: Negative Input for N Line Current
These pins are differential inputs for N line current. Input range is
120μVrms~600mVrms when gain is '1'.
VP
VN
16
15 I Analog
VP: Positive Input for Voltage
VN: Negative Input for Voltage
These pins are differential inputs for voltage. Input range is
120μVrms~600mVrms.
NC 9, 12, 19 NC: These pins could be left open or connect to ground.
CS 24 I LVTTL
CS: Chip Select (Active Low)
In 4-wire SPI mode, this pin must be driven from high to low for each read/
write operation, and maintain low for the entire operation. In 3-wire SPI
mode, this pin must be low all the time. Refer to section 4.1.
SCLK 25 I LVTTL
SCLK: Serial Clock
This pin is used as the clock for the SPI interface. Data on SDI is shifted into
the chip on the rising edge of SCLK while data on SDO is shifted out of the
chip on the falling edge of SCLK.
SDO 26 OZ LVTTL
SDO: Serial Data Output
This pin is used as the data output for the SPI interface. Data on this pin is
shifted out of the chip on the falling edge of SCLK.
SDI 27 I LVTTL
SDI: Serial Data Input
This pin is used as the data input for the SPI interface. Address and data on
this pin is shifted into the chip on the rising edge of SCLK.
MMD1
MMD0
1
28 ILVTTL
MMD1/0: Metering Mode Configuration
00: anti-tampering mode (larger power);
01: L line mode (fixed L line);
10: L+N mode (applicable for single-phase three-wire system);
11: flexible mode (line specified by the LNSel bit (MMode, 2BH))
OSCI 22 I LVTTL
OSCI: External Crystal Input
An 8.192 MHz crystal is connected between OSCI and OSCO. There is an
on-chip 10pF capacitor, therefore no need of external capacitors.
M90E25 [Preliminary Datasheet]
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OSCO 23 O LVTTL
OSCO: External Crystal Output
An 8.192 MHz crystal is connected between OSCI and OSCO. There is an
on-chip 10pF capacitor, therefore no need of external capacitors.
CF1 18 OLVTTL
CF1: Active Energy Pulse Output
This pin outputs active energy pulses.
ZX 21 O LVTTL
ZX: Voltage Zero-Crossing Output
This pin is asserted when voltage crosses zero. Zero-crossing mode can be
configured to positive zero-crossing, negative zero-crossing or all zero-
crossing by the Zxcon[1:0] bits (MMode, 2BH).
IRQ 20 O LVTTL
IRQ: Interrupt Output
This pin is asserted when one or more events in the SysStatus register
(01H) occur. It is deasserted when there is no bit set in the SysStatus regis-
ter (01H).
WarnOut 17 O LVTTL
WarnOut: Fatal Error Warning
This pin is asserted when there is metering parameter calibration error or
voltage sag. Refer to section 4.2.
Note 1: All digital inputs are 5V tolerant except for the OSCI pin.
Table-1 Pin Description (Continued)
Name Pin No. I/O
note 1
Type Description
10
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
3 FUNCTIONAL DESCRIPTION
3.1 DYNAMIC METERING RANGE
Accuracy is 0.1% for active energy metering over a dynamic range of 5000:1 (typical). Refer to Table-2.
3.2 STARTUP AND NO-LOAD POWER
Startup and no-load power thresholds are programmable. The related registers are listed in Table-3.
The chip will start within 1.2 times of the theoretical startup time of the configured startup power, if startup power is less
than the corresponding power of 20mA when power factor or sinφ is 1.0.
The chip has no-load status bits, the Pnoload bit (EnStatus, 46H). The chip will not output any active pulse (CF1) in
active no-load state.
3.3 ENERGY REGISTERS
The M90E25 provides energy pulse output CF1 which is proportionate to active energy. Energy is usually accumulated
by adding the CF1 pulses in system applications. Alternatively, the M90E25 provides energy registers. There are forward
(inductive), reverse (capacitive) and absolute energy registers. Refer to Tabl e- 4.
Each energy register is cleared after read. The resolution of energy registers is 0.1CF, i.e. one LSB represents 0.1
energy pulse.
Table-2 Active Energy Metering Error
Current Power Factor Error(%)
20mA I50mA 1.0 ±0.2
50mA I100A ±0.1
50mA I100mA 0.5 (Inductive)
0.8 (Capacitive)
±0.2
100mA I100A ±0.1
Note: Shunt resistor is 250 μΩ or CT ratio is 1000:1 and load resistor is 6Ω.
Table-3 Threshold Configuration for Startup and No-Load Power
Threshold Register
Threshold for Active Startup Power PStartTh, 27H
Threshold for Active No-load Power PNolTh, 28H
Table-4 Energy Registers
Energy Register
Forward Active Energy APenergy, 40H
Reverse Active Energy ANenergy, 41H
Absolute Active Energy ATenergy, 42H
M90E25 [Preliminary Datasheet]
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11
3.4 N LINE METERING AND ANTI-TAMPERING
3.4.1 METERING MODE AND L/N LINE CURRENT SAMPLING GAIN CONFIGURATION
The M90E25 has two current sampling circuits with N line metering and anti-tampering functions. The MMD1 and MMD0
pins are used to configure the metering mode. Refer to Table-5.
The M90E25 has two current sampling circuits with different gain configurations. L line gain can be 1, 4, 8, 16 and 24,
and N line gain can be 1, 2 and 4. The configuration is made by the MMode register (2BH). Generally L line can be sampled
over shunt resistor or CT. N line can be sampled over CT for isolation consideration. Note that Rogowski coil is not sup-
ported.
3.4.2 ANTI-TAMPERING MODE
Threshold
In anti-tampering mode, the power difference threshold between L line and N line can be: 1%, 2%,... 12%, 12.5%,
6.25%, 3.125% and 1.5625%, altogether 16 choices. The configuration is made by the Pthresh[3:0] bits (MMode, 2BH) and
the default value is 3.125%.
Compare Method
In anti-tampering mode, the compare method is as follows:
If current metering line is L line and
N line is switched as the metering line, otherwise L line keeps as the metering line.
If current metering line is N line and
L line is switched as the metering line, otherwise N line keeps as the metering line.
This method can achieve hysteresis around the threshold automatically. L line is employed after reset by default.
Special Treatment at Low Power
When power is low, general factors such as the quantization error or calibration difference between L line and N line
might cause the power difference to be exceeded. To ensure L line and N line to start up normally, special treatment as fol-
lows is adopted:
The line with higher power is selected as the metering line when both L line and N line power are lower than 8 times of
the startup power but higher than the startup power.
Table-5 Metering Mode
MMD1 MMD0 Metering Mode CF1 Output
0 0 Anti-tampering Mode (larger power) CF1 represents the larger energy line. Refer to section 3.4.2.
0 1 L Line Mode (fixed L line) CF1 represents L line energy all the time.
10L+N Mode (applicable for single-phase three-
wire system) CF1 represents the arithmetic sum of L line and N line energy
11Flexible Mode (line specified by the LNSel bit
(MMode, 2BH)) CF1 represents energy of the specified line.
Threshold100%*
Power ActiveLine L
Power ActiveLine L-Power ActiveLine N >
Threshold100%*
Power ActiveLine N
Power ActiveLine N-Power ActiveLine L >
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3.5 MEASUREMENT AND ZERO-CROSSING
3.5.1 MEASUREMENT
The M90E25 has the following measurements:
voltage rms
current rms (L line/N line)
mean active power (L line/N line)
voltage frequency
power factor (L line/N line)
phase angle between voltage and current (L line/N line)
mean apparent power (L line/N line)
The above measurements are all calculated with fiducial error except for frequency. The frequency accuracy is 0.01Hz,
and the other measurement accuracy is 0.5%. Fiducial error is calculated as follow:
Where Umea is the measured voltage, Ureal is the actual voltage and UFV is the fiducial value.
3.5.2 ZERO-CROSSING
The ZX pin is asserted when the sampling voltage crosses zero. Zero-crossing mode can be configured to positive zero-
crossing, negative zero-crossing and all zero-crossing by the Zxcon[1:0] bits (MMode, 2BH). Refer to section 6.4.
The zero-crossing signal can facilitate operations such as relay operation and power line carrier transmission in typical
smart meter applications.
Table-6 The Measurement Format
Measurement Fiducial Value
(FV) M90E25 Defined Format Range Comment
Voltage rms Un XXX.XX 0~655.35V
Current rms
note 1, note 2
Imax
as 4Ib XX.XXX 0~65.535A
Active Power
note 1
maximum power
as Un*4Ib XX.XXX -32.768~+32.767
kW Complement, MSB as the sign bit
Apparent Power
note 1
Un*4Ib XX.XXX 0~+32.767 kVA Complement, MSB always '0'
Frequency fn XX.XX 45.00~65.00 Hz
Power Factor
note 3
1.000 X.XXX -1.000~+1.000 Signed, MSB as the sign bit
Phase Angle
note 4
180° XXX.X -180°~+180° Signed, MSB as the sign bit
Note 1: All registers are of 16 bits. For cases when the current and active/apparent power goes beyond the above range, it is suggested
to be handled by microcontroller (MCU) in application. For example, register value can be calibrated to 1/2 of the actual value during cal-
ibration, then multiply 2 in application. Note that if the actual current is twice of that of the M90E25, the actual active/apparent power is
also twice of that of the chip.
Note 2: The accuracy is not guaranteed when the current is lower than 15mA. Note that the tolerance is 25 mA at IFV of 5A and fiducial
accuracy of 0.5%.
Note 3: Power factor is obtained by active power dividing apparent power
Note 4: Phase angle is obtained when voltage/current crosses zero at the frequency of 256kHz. Precision is not guaranteed at small
current.
100%*
U
U-U
rrorFiducial_E
FV
realmea
=
M90E25 [Preliminary Datasheet]
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13
3.6 CALIBRATION
Calibration includes metering and measurement calibration.
Metering Calibration
The M90E25 design methodology guarantees the accuracy over the entire dynamic range, after metering calibration at one
specific current, i.e. the basic current of Ib.
The calibration procedure includes the following steps:
1. Calibrate gain at unity power factor;
2. Calibrate phase angle compensation at 0.5 inductive power factor.
Generally, line current sampling is susceptible to the circuits around the sensor when shunt resistor is employed as the
current sensor in L line. For example, the transformer in the energy meter’s power supply may conduct interference to the
shunt resistor. Such interference will cause perceptible metering error, especially at low current conditions. The total inter-
fere is at a statistically constant level. In this case, the M90E25 provides the power offset compensation feature to improve
metering performance.
L line and N line need to be calibrated sequentially.
Measurement Calibration
Measurement calibration includes gain calibration for voltage rms and current rms.
Considering the possible nonlinearity around zero caused by external components, the M90E25 also provides offset
compensation for voltage rms, current rms and mean active power.
The M90E25 design methodology guarantees automatic calibration for frequency, phase angle and power factor measure-
ment.
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3.7 RESET
The M90E25 has an on-chip power supply monitor circuit with built-in hysteresis. The M90E25 only works within the volt-
age range.
The M90E25 has three means of reset: power-on reset, hardware reset and software reset. All registers resume to their
default value after reset.
Power-on Reset: Power-on reset is initiated during power-up. Refer to section 6.3.
Hardware Reset: Hardware Reset is initiated when the reset pin is pulled low. The width of the reset signal should be over
200μs.
Software Reset: Software Reset is initiated when ‘789AH’ is written to the software reset register (SoftReset, 00H).
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
15
4 INTERFACE
4.1 SERIAL PERIPHERAL INTERFACE (SPI)
SPI is a full-duplex, synchronous channel. There are two SPI modes: four-wire mode and three-wire mode. In four-wire
mode, four pins are used: CS, SCLK, SDI and SDO. In three-wire mode, three pins are used: SCLK, SDI and SDO. Data on
SDI is shifted into the chip on the rising edge of SCLK while data on SDO is shifted out of the chip on the falling edge of
SCLK. The LastSPIData register (06H) stores the 16-bit data that is just read or written.
4.1.1 FOUR-WIRE MODE
In four-wire mode, the CS pin must be driven low for the entire read or write operation. The first bit on SDI defines the
access type and the lower 7-bit is decoded as address.
Read Sequence
As shown in Figure-3, a read operation is initiated by a high on SDI followed by a 7-bit register address. A 16-bit data in
this register is then shifted out of the chip on SDO. A complete read operation contains 24 cycles.
Figure-3 Read Sequence in Four-Wire Mode
Write Sequence
As shown in Figure-4, a write operation is initiated by a low on SDI followed by a 7-bit register address. A 16-bit data is
then shifted into the chip on SDI. A complete write operation contains 24 cycles.
Figure-4 Write Sequence in Four-Wire Mode
CS
SCLK
SDI
SDO
10123456789 111213141516171819202122 24
A0A6 A5 A4 A3 A2 A1
Register Address
High Impedance D15
Don't care
D0
16-bit data
23
D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1
CS
SCLK
SDI
SDO
10123456789 11121314151617181920212223
A0A6 A5 A4 A3 A2 A1
16-bit data
High Impedance
D0D7 D6 D5 D4 D3 D2 D1
Register Address
D15
24
D14D13D12D11D10 D9 D8
16
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4.1.2 THREE-WIRE MODE
In three-wire mode, CS is always at low level. When there is no operation, SCLK keeps at high level. The start of a read
or write operation is triggered if SCLK is consistently low for at least 400μs. The subsequent read or write operation is sim-
ilar to that in four-wire mode. Refer to Figure-5 and Figure-6.
Figure-5 Read Sequence in Three-Wire Mode
Figure-6 Write Sequence in Three-Wire Mode
CS
SCLK
10123456789 11121314151617181920212223
Register address
24 1234
Low 400μs
Drive Low
SDI
SDO
A0A6 A5 A4 A3 A2 A1
Hign Impedance D
15
Don't care
16-bit data
D
14
D
13
D
12
D
11
D
10
D
9
D
8
D
7
D
6
D
5
D
4
D
3
D
2
D
0
D
1
Dont care A6 A5 A4
High Impedance
Low 400μs
CS
SCLK
SDI
SDO
10123456789 11121314151617181920212223
A0A6 A5 A4 A3 A2 A1
16-bit data
High Impedance
D
0
D
7
D
6
D
5
D
4
D
3
D
2
D
1
Register Address
D
14
D
15
24
D
13
D
12
D
11
D
10
D
9
D
8
1234
A6 A5 A4Don't care
Drive low
Low 400μsLow 400μs
Don't care
M90E25 [Preliminary Datasheet]
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17
4.1.3 TIMEOUT AND PROTECTION
Timeout occurs if SCLK does not toggle for 6ms in both four-wire and three-wire modes. When timeout, the read or write
operation is aborted.
If there are more than 24 SCLK cycles when CS is driven low in four-wire mode or between two starts in three-wire mode,
writing operation is prohibited while normal reading operation can be completed by taking the first 24 SCLK cycles as the
valid ones. However, the reading result might not be the intended one.
A read access to an invalid address returns all zero. A write access to an invalid address is discarded.
Tab le-7 and Table-8 list the read or write result in different conditions.
Table-7 Read / Write Result in Four-Wire Mode
Condition Result
Operation Timeout SCLK Cycles
note 1
Read/Write
Status
LastSPIData
Register Update
Read
-
note 2
>=24 Normal Read Yes
-
note 2
<24 Partial Read No
Write
No =24 Normal Write Yes
No !=24 No Write No
Yes - No Write No
Note 1: The number of SCLK cycles when CS is driven low or the number of SCLK cycles before timeout if any.
Note 2: '-' stands for Don't Care.
Table-8 Read / Write Result in Three-Wire Mode
Condition Result
Operation Timeout SCLK Cycles
note 1
Read/Write Status
LastSPIData
Register Update
Read
No >=24
note 2
Normal Read Yes
Timeout after 24 cycles >24 Normal Read Yes
Timeout before 24 cycles -
note 3
Partial Read No
Timeout at 24 cycles =24 Normal Read Yes
Write
No =24 Normal Write Yes
No !=24 No Write No
Yes - No Write No
Note 1: The number of SCLK cycles between 2 starts or the number of SCLK cycles before timeout if any.
Note 2: There is no such case of less than 24 SCLK cycles when there is no timeout in three-wire mode, because the first few SCLK
cycles in the next operation is counted into this operation. In this case, data is corrupted.
Note 3: '-' stands for Don't Care.
18
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Atmel-46001A-SE-M90E25-Datasheet_041814
4.2 WARNOUT PIN FOR FATAL ERROR WARNING
Fatal error warning is raised through the WarnOut pin in two cases: checksum calibration error and voltage sag.
Calibration Error
The M90E25 performs diagnosis on a regular basis for important parameters such as calibration parameters and meter-
ing configuration. When checksum is not correct, the CalErr[1:0] bits (SysStatus, 01H) are set, and both the WarnOut pin
and the IRQ pin are asserted. When checksum is not correct, the metering part does not work to prevent a large number of
pulses during power-on or any abnormal situation upon incorrect parameters.
Voltage Sag
Voltage sag is detected when voltage is continuously below the voltage sag threshold for one cycle which starts from any
zero-crossing point. Voltage threshold is configured by the SagTh register (03H). Refer to section 6.5.
When voltage sag occurs, the SagWarn bit (SysStatus, 01H) is set and the WarnOut pin is asserted if the FuncEn regis-
ter (02H) enables voltage sag warning through the WarnOut pin. This function helps reduce power-down detection circuit in
system design. In addition, the method of judging voltage sag by detecting AC side voltage eliminates the influence of large
capacitor in traditional rectifier circuit, and can detect voltage sag earlier.
4.3 LOW COST IMPLEMENTATION IN ISOLATION WITH MCU
The following functions can be achieved at low cost when the M90E25 is isolated from the MCU:
SPI: MCU can perform read and write operations through low speed optocoupler (e.g. PS2501) when the M90E25 is iso-
lated from the MCU. The SPI interface can be of 3-wire or 4-wire.
Energy Pulses CF1: Energy can be accumulated by reading values in corresponding energy registers. CF1 can also
connect to the optocoupler and the energy pulse light can be turned on by CF1.
Fatal Error WarnOut: Fatal error can be acquired by reading the CalErr[1:0] bits (SysStatus, 01H).
IRQ: IRQ interrupt can be acquired by reading the SysStatus register (01H).
Reset: The M90E25 is reset when ‘789AH’ is written to the software reset register (SoftReset, 00H).
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
19
5REGISTER
5.1 REGISTER LIST
Table-9 Register List
Register
Address Register Name Read/Write Type Functional Description Page
Status and Special Register
00H SoftReset W Software Reset P21
01H SysStatus R/C System Status P22
02H FuncEn R/W Function Enable P23
03H SagTh R/W Voltage Sag Threshold P23
04H SmallPMod R/W Small-Power Mode P24
06H LastSPIData R Last Read/Write SPI Value P24
Metering Calibration and Configuration Register
20H CalStart R/W Calibration Start Command P25
21H PLconstH R/W High Word of PL_Constant P25
22H PLconstL R/W Low Word of PL_Constant P26
23H Lgain R/W L Line Calibration Gain P26
24H Lphi R/W L Line Calibration Angle P26
25H Ngain R/W N Line Calibration Gain P27
26H Nphi R/W N Line Calibration Angle P27
27H PStartTh R/W Active Startup Power Threshold P27
28H PNolTh R/W Active No-Load Power Threshold P28
2BH MMode R/W Metering Mode Configuration P29
2CH CS1 R/W Checksum 1 P31
Measurement Calibration Register
30H AdjStart R/W Measurement Calibration Start Command P32
31H Ugain R/W Voltage rms Gain P32
32H IgainL R/W L Line Current rms Gain P33
33H IgainN R/W N Line Current rms Gain P33
34H Uoffset R/W Voltage Offset P33
35H IoffsetL R/W L Line Current Offset P34
36H IoffsetN R/W N Line Current Offset P34
37H PoffsetL R/W L Line Active Power Offset P34
39H PoffsetN R/W N Line Active Power Offset P35
3BH CS2 R/W Checksum 2 P36
Energy Register
40H APenergy R/C Forward Active Energy P37
41H ANenergy R/C Reverse Active Energy P38
42H ATenergy R/C Absolute Active Energy P38
46H EnStatus R Metering Status P39
Measurement Register
48H Irms R L Line Current rms P40
49H Urms R Voltage rms P40
4AH Pmean R L Line Mean Active Power P41
4CH Freq R Voltage Frequency P41
20
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
4DH PowerF R L Line Power Factor P42
4EH Pangle R Phase Angle between Voltage and L Line Current P42
4FH Smean R L Line Mean Apparent Power P43
68H Irms2 R N Line Current rms P43
6AH Pmean2 R N Line Mean Active Power P44
6DH PowerF2 R N Line Power Factor P44
6EH Pangle2 R Phase Angle between Voltage and N Line Current P45
6FH Smean2 R N Line Mean Apparent Power P45
Table-9 Register List (Continued)
Register
Address Register Name Read/Write Type Functional Description Page
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
21
5.2 STATUS AND SPECIAL REGISTER
SoftReset
Software Reset
Address: 00H
Type: Write
Default Value: 0000H
Bit Name Description
15 - 0 SoftRe-
set[15:0] Software reset register. The XXXXXX resets if only 789AH is written to this register.
22
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
SysStatus
System Status
Address: 01H
Type: Read/Clear
Default Value: 0000H
Bit Name Description
15 - 14 CalErr[1:0]
These bits indicate CS1 checksum status.
00: CS1 checksum correct (default)
11: CS1 checksum error. At the same time, the WarnOut pin is asserted.
13 - 12 AdjErr[1:0]
These bits indicate CS2 checksum status.
00: CS2 checksum correct (default)
11: CS2 checksum error.
11 - 8 - Reserved.
7 LNchange
This bit indicates whether there is any change of the metering line (L line and N line).
0: metering line no change (default)
1: metering line changed
6-
Reserved.
5 RevPchg
This bit indicates whether there is any change with the direction of active energy.
0: direction of active energy no change (default)
1: direction of active energy changed
This status is enabled by the RevPEn bit (FuncEn, 02H).
4 - 2 - Reserved.
1SagWarn
This bit indicates the voltage sag status.
0: no voltage sag (default)
1: voltage sag
Voltage sag is enabled by the SagEn bit (FuncEn, 02H).
Voltage sag status can also be reported by the WarnOut pin. It is enabled by the SagWo bit(FuncEn,
02H).
0-
Reserved.
Note: Any of the above events will prompt the IRQ pin to be asserted, which can be supplied to external MCU as an interrupt.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
23
FuncEn
Function Enable
SagTh
Voltage Sag Threshold
Address: 02H
Type: Read/Write
Default Value: 000CH
Bit Name Description
15 - 6 - Reserved.
5 SagEn
This bit determines whether to enable the voltage sag interrupt.
0: disable (default)
1: enable
4SagWo
This bit determines whether to enable voltage sag to be reported by the WarnOut pin.
0: disable (default)
1: enable
3-
Reserved.
2 RevPEn
This bit determines whether to enable the direction change interrupt of active energy.
0: disable
1: enable (default)
1 - 0 - Reserved.
Address: 03H
Type: Read/Write
Default Value: 1D6AH
Bit Name Description
15 - 0 SagTh[15:0]
Voltage sag threshold configuration. Data format is XXX.XX. Unit is V.
The power-on value of SagTh is 1D6AH, which is calculated by 22000*sqrt(2)*0.78/(4*Ugain/32768)
For details, please refer to application note 46101.
24
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
SmallPMod
Small-Power Mode
LastSPIData
Last Read/Write SPI Value
Address: 04H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 SmallP-
Mod[15:0]
Small-power mode command.
A987H: small-power mode. The relationship between the register value of L line and N line active power
in small-power mode and normal mode is:
power in normal mode = power in small-power mode *10*Igain*Ugain /2^42
Others: Normal mode.
Small-power mode is mainly used in the power offset calibration.
Address: 06H
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 LastSPI-
Data[15:0]
This register stores the data that is just read or written through the SPI interface. Refer to Table-7 and
Tab l e - 8.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
25
5.3 METERING/ MEASUREMENT CALIBRATION AND CONFIGURATION
5.3.1 METERING CALIBRATION AND CONFIGURATION REGISTER
CalStart
Calibration Start Command
PLconstH
High Word of PL_Constant
Address: 20H
Type: Read/Write
Default Value: 6886H
Bit Name Description
15 - 0 CalStart[15:0]
Metering calibration start command:
6886H: Power-on value. Metering function is disabled.
5678H: Metering calibration startup command. After 5678H is written to this register, registers 21H-2BH
resume to their power-on values. The M90E25 starts to meter and output energy pulses regardless
of the correctness of diagnosis. The CalErr[1:0] bits (SysStatus, 01H) are not set and the WarnOut/
IRQ pins do not report any warning/interrupt.
8765H: Check the correctness of the 21H-2BH registers. If correct, normal metering. If not correct, meter-
ing function is disabled, the CalErr[1:0] bits (SysStatus, 01H) are set and the WarnOut/IRQ pins
report warning/interrupt.
Others: Metering function is disabled. The CalErr[1:0] bits (SysStatus, 01H) are set and the WarnOut/IRQ
pins report warning/interrupt.
Address: 21H
Type: Read/Write
Default Value: 0015H
Bit Name Description
15 - 0 PLcon-
stH[15:0]
The PLconstH[15:0] and PLconstL[15:0] bits are high word and low word of PL_Constant respectively.
PL_Constant is a constant which is proportional to the sampling ratios of voltage and current, and
inversely proportional to the Meter Constant. PL_Constant is a threshold for energy calculated inside the
chip, i.e., energy larger than PL_Constant will be accumulated in the corresponding energy registers and
then output on CF1.
It is suggested to set PL_constant as a multiple of 4 so as to double or redouble Meter Constant in low
current state to save verification time.
Note: PLconstH takes effect after PLconstL are configured.
For details, please refer to application note 46101.
26
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
PLconstL
Low Word of PL_Constant
Lgain
L Line Calibration Gain
Lphi
L Line Calibration Angle
Address: 22H
Type: Read/Write
Default Value: D174H
Bit Name Description
15 - 0 PLcon-
stL[15:0]
The PLconstH[15:0] and PLconstL[15:0] bits are high word and low word of PL_Constant respectively.
It is suggested to set PL_constant as a multiple of 4. For details, please refer to application note 46101.
Address: 23H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 Lgain[15:0] L line calibration gain. For details, please refer to application note 46101.
Address: 24H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 Lphi[15:0] L line calibration phase angle. For details, please refer to application note 46101.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
27
Ngain
N Line Calibration Gain
Nphi
N Line Calibration Angle
PStartTh
Active Startup Power Threshold
Address: 25H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 Ngain[15:0] N line calibration gain. For details, please refer to application note 46101.
Address: 26H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 Nphi[15:0] N line calibration phase angle. For details, please refer to application note 46101.
Address: 27H
Type: Read/Write
Default Value: 08BDH
Bit Name Description
15 - 0 PStartTh[15:0
] Active startup power threshold. For details, please refer to application note 46101.
28
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Atmel-46001A-SE-M90E25-Datasheet_041814
PNolTh
Active No-Load Power Threshold
Address: 28H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 PNolTh[15:0] Active no-load power threshold. For details, please refer to application note 46101.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
29
MMode
Metering Mode Configuration
Address: 2BH
Type: Read/Write
Default Value: 9422H
Bit Name Description
15 - 13 Lgain[2:0]
L line current gain, default value is ‘100’.
12 - 11 Ngain[1:0]
N line current gain
00: 2
01: 4
10: 1 (default)
11: 1
10 LNSel
This bit specifies metering as L line or N line when metering mode is set to flexible mode by MMD1 and
MMD0 pins.
0: N line
1: L line (default)
9 - 8 DisHPF[1:0]
These bits configure the High Filter Pass (HPF) after ADC. There are two first-order HPF in serial: HPF1
and HPF0. The configuration are applicable to all channels:
7Amod
CF1 output for active power:
0: forward or reverse energy pulse output (default)
1: absolute energy pulse output
6-
Reserved.
Lgain2 Lgain1 Lgain0 Current Channel Gain
1XX 1
000 4
001 8
010 16
011 24
DisHPF1 DisHPF 0 HPF Configuration
00
enable HPF1 and HPF0
(default)
0 1 enable HPF1, disable HPF0;
1 0 disable HPF1, enable HPF0;
1 1 disable HPF1 and HPF0
30
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
5 - 4 Zxcon[1:0]
These bits configure zero-crossing mode. The ZX pin outputs 5ms-width high level when voltage crosses
zero.
00: positive zero-crossing
01: negative zero-crossing
10: all zero-crossing: both positive and negative zero-crossing (default)
11: no zero-crossing output
3 - 0 Pthresh[3:0]
These bits configure the L line and N line power difference threshold in anti-tampering mode.
Pthresh
3
Pthresh
2
Pthresh
1 Pthresh0 Threshold
0000 12.5%
0 0 0 1 6.25%
0 0 1 0 3.125% (default)
0 0 1 1 1.5625%
0100 1%
0101 2%
0110 3%
0111 4%
1000 5%
1001 6%
1010 7%
1011 8%
1100 9%
1 1 0 1 10%
1110 11%
1 1 1 1 12%
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
31
CS1
Checksum 1
Address: 2CH
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 CS1[15:0]
The CS1 register should be written after the 21H-2BH registers are written. Suppose the high byte and
the low byte of the 21H-2BH registers are shown in below table.
The calculation of the CS1 register is as follows:
The low byte of 2CH register is: L2C=MOD(H21+H22+...+H2B+L21+L22+...+L2B, 2^8)
The high byte of 2CH register is: H2C=H21 XOR H22 XOR ... XOR H2B XOR L21 XOR L22 XOR ... XOR
L2B
A part of registers are not used. These registers can be dealed as 0000H in CS calculation.
The M90E25 calculates CS1 regularly. If the value of the CS1 register and the calculation by the M90E25
is different when CalStart=8765H, the CalErr[1:0] bits (SysStatus, 01H) are set and the WarnOut and IRQ
pins are asserted.
Note: The readout value of the CS1 register is the calculation by the M90E25, which is different from
what is written.
Register Address
High
Byte
Low
Byte
21H H21 L21
22H H22 L22
23H H23 L23
24H H24 L24
25H H25 L25
26H H26 L26
27H H27 L27
28H H28 L28
29H H29 L29
2AH H2A L2A
2BH H2B L2B
32
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5.3.2 MEASUREMENT CALIBRATION REGISTER
AdjStart
Measurement Calibration Start Command
Ugain
Voltage rms Gain
Address: 30H
Type: Read/Write
Default Value: 6886H
Bit Name Description
15 - 0 AdjStart[15:0]
Measurement Calibration Start Command
6886H: Power-on value. No measurement.
5678H: Measurement calibration startup command. After 5678H is written to this register, registers 31H-
3AH resume to their power-on values. The M90E25 starts to measure regardless of the correct-
ness of diagnosis. The AdjErr[1:0] bits (SysStatus, 01H) are not set and the IRQ pin does not
report any interrupt.
8765H: Check the correctness of the 31H-3AH registers. If correct, normal measurement. If not correct,
measurement function is disabled, the AdjErr[1:0] bits (SysStatus, 01H) are set and the IRQ pin
reports interrupt.
Others: No measurement. The AdjErr[1:0] bits (SysStatus, 01H) are set and the IRQ pin reports interrupt.
Address: 31H
Type: Read/Write
Default Value: 6720H
Bit Name Description
15 - 0 Ugain[15:0] Voltage rms Gain. For details, please refer to application note 46101.
Note: the Ugain15 bit should only be '0'
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
33
IgainL
L Line Current rms Gain
IgainN
N Line Current rms Gain
Uoffset
Voltage Offset
Address: 32H
Type: Read/Write
Default Value: 7A13H
Bit Name Description
15 - 0 IgainL[15:0] L Line Current rms Gain, For details, please refer to application note 46101.
Address: 33H
Type: Read/Write
Default Value: 7530H
Bit Name Description
15 - 0 IgainN[15:0] N Line Current rms Gain. For details, please refer to application note 46101.
Address: 34H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 Uoffset[15:0] Voltage offset. For calculation method, please refer to application note 46101.
34
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Atmel-46001A-SE-M90E25-Datasheet_041814
IoffsetL
L Line Current Offset
IoffsetN
N Line Current Offset
PoffsetL
L Line Active Power Offset
Address: 35H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 IoffsetL[15:0] L line current offset. For calculation method, please refer to application note 46101.
Address: 36H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 IoffsetN[15:0] N line current offset. For calculation method, please refer to application note 46101.
Address: 37H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 PoffsetL[15:0] L line active power offset.
Complement, MSB is the sign bit. For calculation method, please refer to application note 46101.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
35
PoffsetN
N Line Active Power Offset
Address: 39H
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 PoffsetN[15:0] N line active power offset.
Complement, MSB is the sign bit. For calculation method, please refer to application note 46101.
36
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
CS2
Checksum 2
Address: 3BH
Type: Read/Write
Default Value: 0000H
Bit Name Description
15 - 0 CS2[15:0]
The CS2 register should be written after the 31H-3AH registers are written. Suppose the high byte and
the low byte of the 31H-3AH registers are shown in below table.
The calculatiion of the CS2 register is as follows:
The low byte of 3BH register is: L3B=MOD(H31+H32+...+H3A+L31+L32+...+L3A, 2^8)
The high byte of 3BH register is: H3B=H31 XOR H32 XOR ... XOR H3A XOR L31 XOR L32 XOR ... XOR
L3A
The M90E25 calculates CS2 regularly. If the value of the CS2 register and the calculation by the M90E25
is different when AdjStart=8765H, the AdjErr[1:0] bits (SysStatus, 01H) are set.
Note: The readout value of the CS2 register is the calculation by the XXXXXX, which is different from
what is written.
Register Address
High
Byte
Low
Byte
31H H31 L31
32H H32 L32
33H H33 L33
34H H34 L34
35H H35 L35
36H H36 L36
37H H37 L37
38H H38 L38
39H H39 L39
3AH H3A L3A
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
37
5.4 ENERGY REGISTER
Theory of Energy Registers
The internal energy resolution is 0.01 pulse. Within 0.01 pulse, forward and reverse energy are counteracted. When energy exceeds
0.01 pulse, the respective forward/reserve energy is increased. The forward and reverse energy are not counteracted in absolute energy
registers. Take the example of active energy, suppose:
T0: Forward energy is 12.34 pulses and reverse energy is 1.23 pulses;
From T0 to T1: 0.005 forward pulse appeared
From T1 to T2: 0.004 reverse pulse appeared
From T2 to T3: 0.003 reverse pulse appeared
When forward/reverse energy or absolute energy reaches 0.1 pulse, the respective register is updated. When forward/reverse energy or
absolute energy reaches 1 pulse, the CF1 pins outputs pulse and the REVP/REVQ bits (EnStatus, 46H) are updated.
Absolute energy might be more than the sum of forward and reverse energies. If “consistency” is required between absolute energy and
forward/reverse energy in system application, absolute energy can be obtained by calculating the readout of the forward and reverse
energy registers.
APenergy
Forward Active Energy
T0 T1 T2 T3
Forward Active Pulse 12.34 12.345 12.341 12.34
Reserve Active Pulse 1.23 1.23 1.23 1.232
Absolute Active Pulse 13.57 13.575 13.579 13.582
Address: 40H
Type: Read/Clear
Default Value: 0000H
Bit Name Description
15 - 0 APen-
ergy[15:0]
Forward active energy; cleared after read.
Data format is XXXX.X pulses. Resolution is 0.1 pulse. Maximum is 6553.5 pulses.
When the accumulation of this register has achieved FFFFH, the continuation accumulation will return to
0000H.
38
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
ANenergy
Reverse Active Energy
ATenergy
Absolute Active Energy
Address: 41H
Type: Read/Clear
Default Value: 0000H
Bit Name Description
15 - 0 ANen-
ergy[15:0]
Reverse active energy, cleared after read.
Data format is XXXX.X pulses. Resolution is 0.1 pulse. Maximum is 6553.5 pulses.
When the accumulation of this register has achieved FFFFH, the continuation accumulation will return to
0000H.
Address: 42H
Type: Read/Clear
Default Value: 0000H
Bit Name Description
15 - 0 ATen-
ergy[15:0]
Absolute active energy, cleared after read.
Data format is XXXX.X pulses. Resolution is 0.1 pulse. Maximum is 6553.5 pulses.
When the accumulation of this register has achieved FFFFH, the continuation accumulation will return to
0000H.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
39
EnStatus
Metering Status
Address: 46H
Type: Read
Default Value After Power On: C800H
Bit Name Description
15 - Reserved.
14 Pnoload
This bit indicates whether the M90E25 is in active no-load status.
0: not active no-load state
1: active no-load state
13 - Reserved.
12 RevP
This bit indicates the direction of the last CF1 (active output).
0: active forward
1: active reverse
Note: This bit is always '0' when the CF1 output is configured to be absolute energy.
11 Lline
This bit indicates the current metering line in anti-tampering mode.
0: N line
1: L line
10 - 2 - Reserved.
1 - 0 LNMode[1:0]
These bits indicate the configuration of MMD1 and MMD0 pins. Their relationship is as follows:
MMD
1
MMD
0
LNmo
d1
LNmo
d0 L/N Metering Mode
0 0 0 0 anti-tampering mode (larger power)
0 1 0 1 L line mode (fixed L line)
10 1 0
L+N mode (applicable for single-phase three-wire
system)
11 1 1
Flexible mode (Line specified by the LNSel bit
(MMode, 2BH))
40
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
5.5 MEASUREMENT REGISTER
Irms
L Line Current rms
Urms
Voltage rms
Address: 48H
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Irms[15:0]
L line current rms.
Data format is XX.XXX, which corresponds to 0 ~ 65.535A.
For cases when the current exceeds 65.535A, it is suggested to be handled by MCU in application. For
example, the register value can be calibrated to 1/2 of the actual value during calibration, then multiplied
by 2 in application.
Address: 49H
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Urms[15:0] Voltage rms.
Data format is XXX.XX, which corresponds to 0 ~ 655.35V.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
41
Pmean
L Line Mean Active Power
Freq
Voltage Frequency
Address: 4AH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Pmean[15:0]
L line mean active power.
Complement, MSB is the sign bit. Data format is XX.XXX, which corresponds to -32.768~+32.768kW.
If current is specially handle by MCU, the power of the M90E25 and the actual power have the same mul-
tiple relationship as the current.
Address: 4CH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Freq[15:0]
Voltage frequency.
Data format is XX.XX. Frequency measurement range is 45.00~65.00Hz. For example, 1388H corre-
sponds to 50.00Hz.
42
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
PowerF
L Line Power Factor
Pangle
Phase Angle between Voltage and L Line Current
Address: 4DH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 PowerF[15:0]
L line power factor.
Signed, MSB is the sign bit. Data format is X.XXX. Power factor range: -1.000~+1.000. For example, 03E
8H corresponds to the power factor of 1.000, and 83E8H corresponds to the power factor of -1.000.
Address: 4EH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Pangle[15:0] L line voltage current angle.
Signed, MSB is the sign bit. Data format is XXX.X. Angle range: -180.0~+180.0 degree.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
43
Smean
L Line Mean Apparent Power
Irms2
N Line Current rms
Address: 4FH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Smean[15:0]
L line mean apparent power.
Complement, MSB is always '0'. Data format is XX.XXX, which corresponds to 0~+32.767kVA.
If current is specially handled by MCU, the power of the M90E25 and the actual power have the same
multiple relationship as the current.
Address: 68H
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Irms2[15:0]
N line current rms.
Data format is XX.XXX, which corresponds to 65.535A.
For cases when the current exceeds 65.535A, it is suggested to be handled by MCU in application. For
example, the register value can be calibrated to 1/2 of the actual value during calibration, then multiplied
by 2 in application.
44
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
Pmean2
N Line Mean Active Power
PowerF2
N Line Power Factor
Address: 6AH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Pmean2[15:0]
N line mean active power.
Complement, MSB is the sign bit. Data format is XX.XXX, which corresponds to -32.768~+32.767kW.
If current is specially handled by MCU, the power of the M90E25 and the actual power have the same
multiple relationship as the current.
Address: 6DH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 PowerF2[15:0
]
N line power factor.
Signed, MSB is the sign bit. Data format is X.XXX. Power factor range: -1.000~+1.000. For example, 03E
8H corresponds to the power factor of 1.000, and 83E8H corresponds to the power factor of -1.000.
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
45
Pangle2
Phase Angle between Voltage and N Line Current
Smean2
N Line Mean Apparent Power
Address: 6EH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Pangle2[15:0] N line voltage current angle
Signed, MSB is the sign bit. Data format is XXX.X. Angle range: -180.0~+180.0 degree.
Address: 6FH
Type: Read
Default Value: 0000H
Bit Name Description
15 - 0 Smean2[15:0]
N line mean apparent power
Complement, MSB is always '0'. Data format is XX.XXX, which corresponds to 0~+32.767kVA.
If current is specially handled by MCU, the power of M90E25 and the actual power have the same multi-
ple relationship as the current.
46
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
6 ELECTRICAL SPECIFICATION
6.1 ELECTRICAL SPECIFICATION
Parameters and Description Min. Typical Max. Unit Test Conditions and Comments
Accuracy
DC Power Supply Rejection Ratio (PSRR) ±0.1 %
VDD=3.3V±0.3V, 100Hz, I=5A, V=220V, L
line shunt resistor 150μΩ, N line CT 1000:1,
sampling resistor 4.8Ω
AC Power Supply Rejection Ratio (PSRR) ±0.1 %
VDD=3.3V superimposes 400mVrms,
100Hz Sinusoidal signal, I=5A, V=220V, L
line shunt resistor 150μΩ, N line CT 1000:1,
sampling resistor 4.8Ω
Active Energy Error (Dynamic Range 5000:1) ±0.1 %
L line current gain is ‘24’; N line current gain
is ‘1’
Channel Characteristics
Sampling Frequency 8kHz
L Line Current Channel Equivalent Input Noise 19.1
Single side band noise (measured at 50Hz,
and PGA gain is ‘24’)
N Line Current Channel Equivalent Input Noise 458.4
Single side band noise (measured at 50Hz,
and PGA gain is ‘1’)
Voltage Channel Equivalent Input Noise 458.4
Single side band noise (measured at 50Hz,
and PGA gain is ‘1’)
Total Harmonic Distortion for Each Channel 80 dB 25°C, PGA gain is ‘1’, 500mVrms input
Active Energy Metering Bandwidth 4kHz
Irms and Vrms Measurement Bandwidth 4kHz
Measurement Error ±0.5 %
Analog Input
L Line Current Channel Differential Input
5μ25m
Vrms
PGA gain is ‘24’
7.5μ37.5m PGA gain is ‘16’
15μ75m PGA gain is ‘8’
30μ150m PGA gain is ‘4’
120μ600m PGA gain is ‘1’
N Line Current Channel Differential Input
30μ150m
Vrms
PGA gain is ‘4’
60μ300m PGA gain is ‘2’
120μ600m PGA gain is ‘1’
Voltage Channel Differential Input 120μ600m Vrms PGA gain is ‘1’
L Line Current Channel Input Impedance 1KΩ
N Line Current Channel Input Impedance 50 KΩ
Voltage Channel Input Impedance 50 KΩ
L Line Current Channel DC Offset 10 mV PGA gain is ‘24’
N Line Current Channel DC Offset 10 mV PGA gain is ‘1’
Voltage Channel DC Offset 10 mV PGA gain is ‘1’
Reference
On-Chip Reference 1.398 1.417 1.440 V Reference voltage test mode
Reference Voltage Temperature Coefficient ±15 ±40 ppm/°C
Clock
Crystal or External Clock 8.192 MHz
The Accuracy of crystal or external clock is
±100 ppm
Hz/nV
Hz/nV
Hz/nV
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
47
SPI Interface
SPI Interface Bit Rate 200 160k bps
Pulse Width
CF1 Pulse Width 80 ms
If T 160 ms, width=80ms; if T<160 ms,
width = 0.5T. Refer to Section 6.6
ESD
Machine Model (MM) 400 V JESD22-A115
Charged Device Model (CDM) 1000 V JESD22-C101
Human Body Model (HBM) 4000 V JESD22-A114
Latch Up ±100 mA JESD78A
Latch Up 4.95 V JESD78A
Operating Conditions
AVDD, Analog Power Supply 2.8 3.3 3.6 V
Metering precision guaranteed within
3.0V~3.6V.
DVDD, Digital Power Supply 2.8 3.3 3.6 V
Metering precision guaranteed within
3.0V~3.6V.
IAVDD, Analog Current 3.75 mA
L line/ N line current channel and voltage
channel are open
IDVDD, Digital Current 2.75 mA VDD=3.3V
DC Characteristics
Digital Input High Level (all digital pins except
OSCI) 2.0 VDD+2.6 V VDD=3.3V±10%,
Digital Input High Level (OSCI) 2.0 VDD+0.3 V VDD=3.3V±10%
Digital Input Low Level 0.8 V VDD=3.3V±10%
Digital Input Leakage Current ±1μAVDD=3.6V, VI=VDD or GND
Digital Output Low Level (CF1) 0.4 V VDD=3.3V, IOL=10mA
Digital Output Low Level (IRQ, WarnOut, ZX,
SDO) 0.4 V VDD=3.3V, IOL=5mA
Digital Output High Level (CF1) 2.4 V VDD=3.3V, IOH=-10mA
Digital Output High Level (IRQ, WarnOut, ZX,
SDO) 2.4 V VDD=3.3V, IOH=-5mA
Digital Output Low Level (OSCO) 0.4 V VDD=3.3V, IOL=1mA
Digital Output High Level (OSCO) 2.4 V VDD=3.3V, IOH=-1mA
48
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
6.2 SPI INTERFACE TIMING
The SPI interface timing is as shown in Figure-7, Figure-8 and Table-10.
Figure-7 4-Wire SPI Timing Diagram
Figure-8 3-Wire SPI Timing Diagram
CS
SCLK
SDI
SDO
tCSH
tCSS
High Impedance High Impedance
tCSD
tCLH tCLL
tDIS tDIH
tPD tDF
Valid Input
Valid Output
tCLD
tDW
SCLK
SDI
SDO High Impedance High Impedance
tCLH tCLL
tDIS tDIH
tPD
Valid Input
Valid Output
tDW
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
49
Table-10 SPI Timing Specification
Symbol Description Min. Typical Max. Unit
tCSH
note 1
Minimum CS High Level Time 30T
note 2
+10 ns
tCSS
note 1
CS Setup Time 3T+10 ns
tCSD
note 1
CS Hold Time 30T+10 ns
tCLD
note 1
Clock Disable Time 1T ns
tCLH Clock High Level Time 30T+10 ns
tCLL Clock Low Level Time 16T+10 ns
tDIS Data Setup Time 3T+10 ns
tDIH Data Hold Time 22T+10 ns
tDW Minimum Data Width 30T+10 ns
tPD Output Delay 14T 15T+20 ns
tDF
note 1
Output Disable Time 16T+20 ns
Note:
1. Not applicable for three-wire SPI.
2. T means SCLK cycle. T=122ns. (Typical value for four-wire SPI)
50
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
6.3 POWER ON RESET TIMING
Figure-9 Power On Reset Timing Diagram
Table-11 Power On Reset Specification
Symbol Description Min. Typical Max. Unit
VHPower On Trigger Voltage 2.47 2.6 2.73 V
VLPower Off Trigger Voltage 2.185 2.3 2.415 V
VH-VLHysteretic Voltage Difference 0.285 0.3 0.315 V
T1Delay Time After Power On 5ms
T2Delay Time After Power Off 10 μs
DVDD
RESET
T1
VH
T2
VL
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
51
6.4 ZERO-CROSSING TIMING
Figure-10 Zero-Crossing Timing Diagram
Table-12 Zero-Crossing Specification
Symbol Description Min. Typical Max. Unit
TZX High Level Width 5ms
TDDelay Time 0.5 ms
ZX
(Positive zero-crossing)
ZX
(Negative zero-crossing)
ZX
(All zero-crossing)
TZX
TD
V
52
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
6.5 VOLTAGE SAG TIMING
Figure-11 Voltage Sag Timing Diagram
Table-13 Voltage Sag Specification
Symbol Description Min. Typical Max. Unit
TDDelay Time 0.5 ms
Voltage Sag
Threshold
WarnOut
IRQ
TD
V
Voltage Sag
Threshold
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
53
6.6 PULSE OUTPUT
Figure-12 Output Pulse Width
6.7 ABSOLUTE MAXIMUM RATING
Parameter Maximum Limit
Relative Voltage Between AVDD and AGND -0.3V~3.7V
Relative Voltage Between DVDD and DGND -0.3V~3.7V
Analog Input Voltage (I1P, I1N, I2P, I2N, VP, VN) -1V~VDD
Digital Input Voltage -0.3V~VDD+2.6V
Operating Temperature Range -40~85 °C
Maximum Junction Temperature 150 °C
Package Type Thermal Resistance θJA Unit Condition
Green SSOP28 63.2 °C/W No Airflow
CFx
Tp=80ms
Tp=0.5T
T160ms 10msT<160ms
Tp=5ms
if T<10ms,
force T=10ms
54
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
ORDERING INFORMATION
Atmel Ordering Code Package Carrier Temperature Range
ATM90E25-YU-R SSOP28 Tape&Reel Industry (-40°C to +85°C)
ATM90E25-YU-B SSOP28 Tube Industry (-40°C to +85°C)
M90E25 [Preliminary Datasheet]
Atmel-46001A-SE-M90E25-Datasheet_041814
55
PACKAGE DIMENSIONS
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56
M90E25 [PRELIMINARY DATASHEET]
Atmel-46001A-SE-M90E25-Datasheet_041814
REVISION HISTORY
Doc. Rev. Date Comments
46001A 04/18/2014 Initial document release in Atmel.
X
XXX
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