M.2 breakout board

The M.2 breakout board is a convenient way to prototype with the B-SoM and M-SoM modules.

Illustration

Block diagram

Block diagram

Board features

Board features
Label Description
1 Cellular modem USB-C (not normally used)
2 SWD debugging connector
3 MCU USB-C (use this one)
4 LiPo battery power switch
5 LiPo battery connector (3-pin, with temperature sensor)
6 DC power switch
7 DC power barrel connector (5.5mm x 2.1mm, center positive)
8 QWIIC (3.3V I2C connector)
9 Grove expansion connector
10 U.FL to SMA connectors
11 Spare M.2 SoM screws
12 NFC U.FL connector (B-SoM only, not available on M-SoM)
13 Expansion connector
15 RESET button
16 RGB status LED
17 MODE button
18 Prototyping area
19 3V3_AUX
20 GND
21 M.2 SoM socket for B-SoM or M-SoM
22 Power module
23 Adafruit Feather connector (for accessories)
25 LiPo charge LED (yellow)
26 LiPo temperature sensor jumper (TS)
27 Power LED (red)

Setup

Install the SoM

The M.2 SoM breakout board requires a Particle M-SoM or B-SoM module. Install it in the M.2 socket (21) and secure it with a thumbscrew.

Connect antennas

The M.2 breakout board can be used with the standard flexible Particle antennas or the SMA adapters included on the breakout board.

  • Plug the cellular antenna into the U.FL connector labeled CELL on the SoM. Remember never to power up this board without the antenna being connected. There is potential to damage the transmitter of the u-blox module if no antenna is connected.
  • If you are planning to use BLE, connect the 2.4 GHz antenna (the smaller one) to the BT U.FL connector on the SoM.
  • The flexible Particle cellular and BLE antennas should be included in the M.2 SoM package, not the breakout board package.
  • SMA antennas are not included with the M.2 breakout board. If used in a product, additional certification would be required to use a SMA antenna.

Install a power module

The M.2 breakout board includes two power modules; select and install the module you wish to use and install it in the power module socket (22).

Note the position of the notch to make sure the power module is installed in the correct orientation and make sure all of the pins are aligned with the socket on the breakout board.

PM-BAT power module

The PM-BAT power module allows the Particle SoM to be powered by a LiPo battery or DC adapter.

  • Install the PM-BAT module in the power module socket (22).
  • Connect the LiPo battery (2).
  • Optionally connect the AC power adapter to VIN (7). With PM-BAT, VIN must be 5-12 VDC.
  • You must use the LiPo battery, AC power adapter, or both, when using PM-BAT. You cannot power by USB only.
  • The LiPo battery can be only be charged by VIN, it cannot be charged from USB.

PM-DC power module

The PM-DC power module allows the Particle SoM to be powered by an AC power adapter or external DC power source.

  • Install the PM-DC module in the power module socket (22).
  • Connect the power adapter to VIN (7). When powering PM-DC by VIN (barrel connector), 4-40 VDC is required at 12 watts.
  • Power on the VIN barrel connector is required when using PM-DC; you cannot power the breakout board only by USB power.

Power on device

Turn on the appropriate power switches (4, 6).

The RGB status LED should turn on. Typically it will blink white once, then blink green though it may display a different pattern.

Device setup and claiming

Connect the USB connector (3) to your computer. This is needed only for setup.

Visit https://setup.particle.io/ to finish setting up your device.

Onboard peripherals

Qwiic (8)

The SparkFun Qwiic system provides an easy way to expand and test various sensors, input devices, and displays. Multiple peripherals can be daisy-chained to a single port. The Adafruit Stemma QT are compatible with Qwiic and can be mixed and matched as well.

For more information, see Qwiic.

Grove connector (9)

Additionally, Grove system of sensors and peripherals from Seeed Systems is another easy way to add peripheral devices. The M.2 breakout board has one Grove connectors connected to pins A1 and A2 that can be used as GPIO or analog inputs. This port cannot be used with I2C or Serial Grove peripherals.

J11 SoM Pin SoM Pin Number
GND
3V3
ADC2 A2 35
ADC1 A1 33

Feather connector (21)

The Feather connector can be used for Adafruit FeatherWings, such as displays, sensors, and Ethernet. You cannot plug a Feather MCU into this socket!

Feather pin mapping - M-SoM

Expansion header

Feather pin mapping - B-SoM

Expansion header

Jumpers (22)

These jumpers connect the Feather A pin side to the M.2 connector. They can also be used to remap pins by using jumper wires instead of solid jumpers.

Jumpers (23)

These jumpers connect the Feather D pin side to the M.2 connector. They can also be used to remap pins by using jumper wires instead of solid jumpers.

LiPo connector

Note that the M.2 breakout board includes a 3-pin JST-PH connector (left), not the 2-pin JST-PH connector on some other Particle devices (right). The TS pin is expected to be connected to a 10K NTC thermistor in the battery pack. The TS jumper (26) must be installed for normal operation with a temperature sensor.

Battery connector

Looking at the exposed end of the connector attached to the battery

If you wish to use a battery without a temperature sensor, remove the TS jumper (26) and use a 3-pin to 2-pin JST-PH adapter, or change the shell of your JST-PH 2-pin connector to a 3-pin shell. The pin can be swapped without cutting, soldering, or crimping. See the battery guide for more information.

If purchasing a LiPo battery from a 3rd-party supplier, beware as the polarity of the JST-PH connector is not standardized and may be reversed. Permanent damage to the breakout board can occur if powered by reverse polarity on the JST connector. See the battery guide for additional information.

3V3_AUX power

Both the PM-BAT and PM-DC power modules support an auxiliary 3.3V power supply. This is used to power the Feather socket 3V3 and the 3V3_AUX rail.

Power module SoM Pin SoM Pin Number
EN_AUX D23 / GPIO1 50

3V3_AUX is powered from 3V3 via a load switch (TPS22918). It can supply up to the full 2A of 3V3. It defaults to off due to a pull-down resistor on EN_AUX. EN_AUX is connected to pin D23; set this pin to output high to enable 3V3_AUX.

// Enable 3V3_AUX
pinMode(D23, OUTPUT);
digitalWrite(D23, HIGH);

PM-BAT interface

The M.2 breakout board can be used with the PM-BAT power module that includes the bq24195 PMIC and MAX17043 fuel gauge chips which interface by the pins below

Power module SoM Pin SoM Pin Number
FUEL_INT A6 45
SDA D0 22
SCL D1 20

Using ethernet

The M.2 breakout board does not contain Ethernet like the previous B-Series Eval board. You can, however, add it using the Adafruit Ethernet FeatherWing in the Feather socket.

Be sure to connect the nRESET and nINTERRUPT pins (on the small header on the short side) to pins D3 and D4 with jumper wires. These are required for proper operation.

The default mapping for the B-SoM and the original B-SoM eval board is listed below, but you may want to use Ethernet pin remapping to reassign the pins.

Particle Pin M.2 Pin Ethernet Pin
D8 CS ETH_CS
A7 RESERVED ETH_RESET
SCK SCK ETH_CLK
MISO MISO ETH_MISO
MOSI MOSI ETH_MOSI
D22 GPIO0 ETH_INT

Using SD card

The M.2 breakout board does not contain a Micro SD card socket as the previous B-Series Eval board did. You can, however, add it using the Adafruit Feather connector.

The Adalogger FeatherWing - RTC + SD Add-on For All Feather Boards contains a Micro SD card socket.

SD Card Pin Feather Pin Description
SCK SCK SPI Clock
MOSI MOSI Data (MCU to SD card)
MISO MISO Data (SD card to MCU)
SDCS D5 Chip select

It is also possible to cut the a trace jumper for SDCS and use a different pin for SDCS. Note that this will use SPI (primary SPI) but the B-Series Eval board use SPI1 so your SD card initialization code will be different.

See the Adafruit tutorial for additional information.

Expansion header

Expansion header - M-SoM

Expansion header M-SoM

Expansion header - B-SoM

Expansion header B-SoM

Full pin listing

Skip past this section (the full pin listing is long)

Module Pin 1 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 1
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 2 (VCC)

Unchanged between B-SoM and M-SoM
Pin Number 2
Pin Name VCC
Description Cellular modem power. Typically 3.9V, can be 3.6V to 4.2V
M.2 connector pin number 2
SoM Common Pin Name VCC

Module Pin 3 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 3
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 4 (VCC)

Unchanged between B-SoM and M-SoM
Pin Number 4
Pin Name VCC
Description Cellular modem power. Typically 3.9V, can be 3.6V to 4.2V
M.2 connector pin number 2
SoM Common Pin Name VCC

Module Pin 5 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 5
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 6 (VCC)

Unchanged between B-SoM and M-SoM
Pin Number 6
Pin Name VCC
Description Cellular modem power. Typically 3.9V, can be 3.6V to 4.2V
M.2 connector pin number 2
SoM Common Pin Name VCC

Module Pin 7 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 7
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 8 (3V3)

B-SoM M-SoM
  Pin Number 8 8
  Pin Name 3V3 3V3
  Description 3.3V used to power MCU 3.3V used to power MCU
M.2 connector pin number 10 8
SoM Common Pin Name 3V3 VCC

Module Pin 9 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 9
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 10 (SOM10)

Unchanged between B-SoM and M-SoM
Pin Number 10
Pin Name SOM10
Description Not currently used, leave unconnected.
M.2 connector pin number 14
SoM Common Pin Name RESERVED

Module Pin 11 (SOM6 / D21)

B-SoM M-SoM
  Pin Number 11 11
Pin Name SOM6 D21
Pin Alternate Name NFC1 n/a
Description NFC Antenna 1. D21 GPIO. Is NFC1 on B-SoM.
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
Supports attachInterrupt n/a Yes
I2S interface n/a I2S RX
Internal pull resistance n/a 22K. No internal pull up or pull down in HIBERNATE sleep mode.
  M.2 connector pin number 17 17
SoM Common Pin Name SOM3 RESERVED

Module Pin 12 (SOM11 / GNSS_TX)

B-SoM M-SoM
  Pin Number 12 12
Pin Name SOM11 GNSS_TX
Description Not currently used, leave unconnected. Cellular modem GNSS UART TX
  M.2 connector pin number 18 18
  SoM Common Pin Name RESERVED RESERVED

Module Pin 13 (SOM7 / D20)

B-SoM M-SoM
  Pin Number 13 13
Pin Name SOM7 D20
Pin Alternate Name NFC2 n/a
Description NFC Antenna 2. NFC2 is the center pin. D20 GPIO. Is NFC2 on B-SoM.
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
Supports attachInterrupt n/a Yes
I2S interface n/a I2S TX
Internal pull resistance n/a ???
  M.2 connector pin number 19 19
SoM Common Pin Name SOM4 RESERVED

Module Pin 14 (D1)

B-SoM M-SoM
  Pin Number 14 14
  Pin Name D1 D1
  Pin Alternate Name D1 D1
  Description I2C SCL. Cannot be used as GPIO. I2C SCL. Cannot be used as GPIO.
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
I2C interface SCL. Use Wire object. SCL. Use Wire object. Use 1.5K to 10K external pull-up resistor.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 20 20
  SoM Common Pin Name SCL SCL

Module Pin 15 (A0)

B-SoM M-SoM
  Pin Number 15 15
  Pin Name A0 A0
  Pin Alternate Name D19 D19
  Description A0 Analog in, GPIO, PWM A0 Analog in, GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone A0, A1, A6, and A7 must have the same frequency. Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 42K
  M.2 connector pin number 23 23
  SoM Common Pin Name ADC0 ADC0

Module Pin 16 (D0)

B-SoM M-SoM
  Pin Number 16 16
  Pin Name D0 D0
  Pin Alternate Name D0 D0
  Description I2C SDA. Cannot be used as GPIO. I2C SDA. Cannot be used as GPIO.
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
I2C interface SDA. Use Wire object. SDA. Use Wire object. Use 1.5K to 10K external pull-up resistor.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 22 22
  SoM Common Pin Name SDA SDA

Module Pin 17 (A1)

B-SoM M-SoM
  Pin Number 17 17
  Pin Name A1 A1
  Pin Alternate Name D18 D18
  Description A1 Analog in, GPIO, PWM A1 Analog in, GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone A0, A1, A6, and A7 must have the same frequency. Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 33 33
  SoM Common Pin Name ADC1 ADC1

Module Pin 18 (MODE)

B-SoM M-SoM
  Pin Number 18 18
  Pin Name MODE MODE
  Pin Alternate Name D20 D20
Description MODE button, has internal pull-up MODE button. Pin number constant is BTN. External pull-up required!
Supports attachInterrupt n/a Yes
  M.2 connector pin number 32 32
  SoM Common Pin Name MODE MODE

Module Pin 19 (A2)

B-SoM M-SoM
  Pin Number 19 19
  Pin Name A2 A2
  Pin Alternate Name D17 D17
  Description A2 Analog in, GPIO A2 Analog in, GPIO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 22K
  M.2 connector pin number 35 35
  SoM Common Pin Name ADC2 ADC2

Module Pin 20 (RST)

B-SoM M-SoM
  Pin Number 20 20
  Pin Name RST RST
Description Hardware reset, active low. Hardware reset, active low. External pull-up required.
  M.2 connector pin number 34 34
  SoM Common Pin Name RESET RESET

Module Pin 21 (A3)

B-SoM M-SoM
  Pin Number 21 21
  Pin Name A3 A3
  Pin Alternate Name D16 D16
Description A3 Analog in, GPIO A3 Analog in, PDM CLK, GPIO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 37 37
  SoM Common Pin Name ADC3 ADC3

Module Pin 22 (TX)

B-SoM M-SoM
  Pin Number 22 22
  Pin Name TX TX
  Pin Alternate Name D9 D9
Description Serial TX, GPIO Serial TX, PWM, GPIO, SPI1 MOSI
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports analogWrite (PWM) No Yes
Supports tone No Yes
  UART serial TX. Use Serial1 object. TX. Use Serial1 object.
SPI interface n/a MOSI. Use SPI1 object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
I2S interface n/a I2S MCLK
Internal pull resistance 13K 2.1K
  M.2 connector pin number 36 36
  SoM Common Pin Name TX TX

Module Pin 23 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 23
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 24 (RX)

B-SoM M-SoM
  Pin Number 24 24
  Pin Name RX RX
  Pin Alternate Name D10 D10
Description Serial RX, GPIO Serial RX, PWM, GPIO, SPI1 MISO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports analogWrite (PWM) No Yes
Supports tone No Yes
  UART serial RX. Use Serial1 object. RX. Use Serial1 object.
SPI interface n/a MISO. Use SPI1 object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 38 38
  SoM Common Pin Name RX RX

Module Pin 25 (A4)

B-SoM M-SoM
  Pin Number 25 25
  Pin Name A4 A4
  Pin Alternate Name D15 D15
Description A4 Analog in, GPIO A4 Analog in, PDM DAT, GPIO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 41 41
  SoM Common Pin Name RESERVED RESERVED

Module Pin 26 (D3)

B-SoM M-SoM
  Pin Number 26 26
  Pin Name D3 D3
  Pin Alternate Name CTS CTS
Description SPI1 MOSI, Serial1 CTS, GPIO, Wire1 SCL D3 GPIO, Serial1 CTS flow control (optional), SPI1 SS
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  UART serial CTS. Use Serial1 object. CTS. Use Serial1 object.
SPI interface MOSI. Use SPI1 object. SS. Use SPI1 object.
  I2C interface SCL. Use Wire1 object. SCL. Use Wire1 object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 40 40
SoM Common Pin Name RESERVED CTS

Module Pin 27 (A5)

B-SoM M-SoM
  Pin Number 27 27
  Pin Name A5 A5
  Pin Alternate Name D14 D14
Description A5 Analog in, GPIO A5 Analog in, PWM, GPIO, shared with pin 53
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
Supports analogWrite (PWM) No Yes
Supports tone No Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
SWD interface n/a SWCLK. 40K pull-down at boot.
Signal used at boot n/a SWCLK. 40K pull-down at boot.
  M.2 connector pin number 43 43
  SoM Common Pin Name RESERVED RESERVED

Module Pin 28 (D2)

B-SoM M-SoM
  Pin Number 28 28
  Pin Name D2 D2
  Pin Alternate Name RTS RTS
Description SPI1 SCK, Serial1 RTS, PWM, GPIO, Wire1 SDA D2 GPIO, Serial RTS flow control (optional), SPI1 SCK
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  UART serial RTS. Use Serial1 object. RTS. Use Serial1 object.
  SPI interface SCK. Use SPI1 object. SCK. Use SPI1 object.
  I2C interface SDA. Use Wire1 object. SDA. Use Wire1 object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 42 42
SoM Common Pin Name RESERVED RTS

Module Pin 29 (A6)

B-SoM M-SoM
  Pin Number 29 29
  Pin Name A6 A6
Pin Alternate Name D16 D29
Description A6 Analog in, PWM, GPIO A6 Analog in, GPIO, PWM, M.2 eval PMIC INT
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone A0, A1, A6, and A7 must have the same frequency. Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 45 45
  SoM Common Pin Name RESERVED RESERVED

Module Pin 30 (SOM0 / CELL USBD+)

B-SoM M-SoM
  Pin Number 30 30
Pin Name SOM0 CELL USBD+
  Pin Alternate Name CELL USBD+ CELL USBD+
Description Cellular Modem USB Data+. Cellular Modem USB Data+
  Input is 5V Tolerant Yes Yes
  M.2 connector pin number 44 44
  SoM Common Pin Name SOM0 SOM0

Module Pin 31 (A7)

B-SoM M-SoM
  Pin Number 31 31
  Pin Name A7 A7
Pin Alternate Name D17 WKP
Description A7 Analog in, GPIO A7 Analog In, WKP, GPIO D28
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogRead Yes Yes
Supports analogWrite (PWM) Yes No
Supports tone A0, A1, A6, and A7 must have the same frequency. No
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 47 47
  SoM Common Pin Name RESERVED RESERVED

Module Pin 32 (SOM1 / CELL USBD-)

B-SoM M-SoM
  Pin Number 32 32
Pin Name SOM1 CELL USBD-
  Pin Alternate Name CELL USBD- CELL USBD-
Description Cellular Modem USB Data-. Cellular Modem USB Data-
  Input is 5V Tolerant Yes Yes
  M.2 connector pin number 46 46
  SoM Common Pin Name SOM1 SOM1

Module Pin 33 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 33
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 34 (D8)

B-SoM M-SoM
  Pin Number 34 34
  Pin Name D8 D8
Pin Alternate Name CS D8
Description GPIO, SPI SS D8 GPIO, SPI SS
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
SPI interface SS. Use SPI object. This is only the default SS/CS pin, you can use any GPIO instead. Default SS for SPI.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 48 48
  SoM Common Pin Name CS CS

Module Pin 35 (SOM14)

Unchanged between B-SoM and M-SoM
Pin Number 35
Pin Name SOM14
Description M.2 pin 51. Not currently used, leave unconnected.
M.2 connector pin number 51
SoM Common Pin Name RESERVED

Module Pin 36 (MISO)

B-SoM M-SoM
  Pin Number 36 36
  Pin Name MISO MISO
  Pin Alternate Name D11 D11
Description SPI MISO, GPIO D11 GPIO, PWM, SPI MISO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports analogWrite (PWM) No Yes
Supports tone No Yes
  SPI interface MISO. Use SPI object. MISO. Use SPI object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 50 50
  SoM Common Pin Name MISO MISO

Module Pin 37 (SOM15 / A5)

B-SoM M-SoM
  Pin Number 37 37
Pin Name SOM15 A5
Pin Alternate Name n/a D14
Description M.2 pin 53. Not currently used, leave unconnected. A5 Analog in, PWM, GPIO, SWCLK, shared with pin 43
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
Supports analogRead n/a Yes
Supports analogWrite (PWM) n/a Yes
Supports tone n/a Yes
Supports attachInterrupt n/a Yes
Internal pull resistance n/a 42K
SWD interface n/a SWCLK. 40K pull-down at boot.
Signal used at boot n/a SWCLK. 40K pull-down at boot.
  M.2 connector pin number 53 53
SoM Common Pin Name RESERVED SWD_CLK

Module Pin 38 (MOSI)

B-SoM M-SoM
  Pin Number 38 38
  Pin Name MOSI MOSI
  Pin Alternate Name D12 D12
Description SPI MOSI, GPIO D12 GPIO, PWM, SPI MOSI
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports analogWrite (PWM) No Yes
Supports tone No Yes
  SPI interface MOSI. Use SPI object. MOSI. Use SPI object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 52 52
  SoM Common Pin Name MOSI MOSI

Module Pin 39 (SOM16 / D27)

B-SoM M-SoM
  Pin Number 39 39
Pin Name SOM16 D27
Description M.2 pin 55. Not currently used, leave unconnected. D27 GPIO, SWDIO (SWD_DATA), do not pull down at boot
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
Supports attachInterrupt n/a Yes
Internal pull resistance n/a 42K
SWD interface n/a SWDIO. 40K pull-up at boot.
Signal used at boot n/a SWDIO. 40K pull-up at boot. Low at boot triggers MCU test mode.
  M.2 connector pin number 55 55
SoM Common Pin Name RESERVED SWD_DATA

Module Pin 40 (SCK)

B-SoM M-SoM
  Pin Number 40 40
  Pin Name SCK SCK
  Pin Alternate Name D13 D13
Description SPI SCK, GPIO D13 GPIO, SPI SCK
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  SPI interface SCK. Use SPI object. SCK. Use SPI object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K 2.1K
  M.2 connector pin number 54 54
  SoM Common Pin Name SCK SCK

Module Pin 41 (SOM17)

Unchanged between B-SoM and M-SoM
Pin Number 41
Pin Name SOM17
Description M.2 pin 57. Not currently used, leave unconnected.
M.2 connector pin number 57
SoM Common Pin Name RESERVED

Module Pin 42 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 42
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 43 (SOM18 / D26)

B-SoM M-SoM
  Pin Number 43 43
Pin Name SOM18 D26
Description M.2 pin 59. Not currently used, leave unconnected. D26 GPIO
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
Supports attachInterrupt n/a Yes
I2S interface n/a I2S WS
Internal pull resistance n/a ???
  M.2 connector pin number 59 59
  SoM Common Pin Name RESERVED RESERVED

Module Pin 44 (SOM12 / D24)

B-SoM M-SoM
  Pin Number 44 44
Pin Name SOM12 D24
Description M.2 pin 58. Not currently used, leave unconnected. D24 GPIO, Serial2 TX, do not pull down at boot
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
UART serial n/a TX. Use Serial2 object.
Supports attachInterrupt n/a Yes
Internal pull resistance n/a 42K
Signal used at boot n/a Low at boot triggers ISP flash download
  M.2 connector pin number 58 58
  SoM Common Pin Name RESERVED RESERVED

Module Pin 45 (RGBR)

B-SoM M-SoM
  Pin Number 45 45
  Pin Name RGBR RGBR
Pin Alternate Name n/a RGBR
  Description RGB LED Red RGB LED Red
Signal used at boot n/a Low at boot triggers trap mode
  M.2 connector pin number 61 61
  SoM Common Pin Name RED RED

Module Pin 46 (SOM13 / D25)

B-SoM M-SoM
  Pin Number 46 46
Pin Name SOM13 D25
Description M.2 pin 60. Not currently used, leave unconnected. GPIO25, Serial2 RX
Supports digitalRead n/a Yes
Supports digitalWrite n/a Yes
UART serial n/a RX. Use Serial2 object.
Supports attachInterrupt n/a Yes
Internal pull resistance n/a 42K
Signal used at boot n/a Goes high at boot
  M.2 connector pin number 60 60
  SoM Common Pin Name RESERVED RESERVED

Module Pin 47 (RGBG)

B-SoM M-SoM
  Pin Number 47 47
  Pin Name RGBG RGBG
Pin Alternate Name n/a RGBG
  Description RGB LED Green RGB LED Green
  M.2 connector pin number 63 63
  SoM Common Pin Name GREEN GREEN

Module Pin 48 (D22)

B-SoM M-SoM
  Pin Number 48 48
  Pin Name D22 D22
Pin Alternate Name GPIO0 D22
Description GPIO D22 D22 GPIO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 62 62
  SoM Common Pin Name GPIO0 GPIO0

Module Pin 49 (RGBB)

B-SoM M-SoM
  Pin Number 49 49
  Pin Name RGBB RGBB
Pin Alternate Name n/a RGBB
  Description RGB LED Blue RGB LED Blue
  M.2 connector pin number 65 65
  SoM Common Pin Name BLUE BLUE

Module Pin 50 (D23)

B-SoM M-SoM
  Pin Number 50 50
  Pin Name D23 D23
Pin Alternate Name GPIO1 D23
Description GPIO D23 D23 GPIO
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 64 64
  SoM Common Pin Name GPIO1 GPIO1

Module Pin 51 (SOM5)

B-SoM M-SoM
  Pin Number 51 51
  Pin Name SOM5 SOM5
  Pin Alternate Name SIM_VCC SIM_VCC
Description Leave unconnected. External SIM support is not available on B-SoM. Leave unconnected, 1.8V/3V SIM Supply Output from R410M.
  M.2 connector pin number 67 67
  SoM Common Pin Name SOM5 SOM5

Module Pin 52 (D4)

B-SoM M-SoM
  Pin Number 52 52
  Pin Name D4 D4
  Pin Alternate Name PWM0 PWM0
Description SPI1 MISO, PWM, GPIO D4 D4 GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone D4, D5, and D6 must have the same frequency. Yes
  SPI interface MISO. Use SPI1 object. MISO. Use SPI1 object.
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
Internal pull resistance 13K ???
  M.2 connector pin number 66 66
  SoM Common Pin Name PWM0 PWM0

Module Pin 53 (SOM6)

B-SoM M-SoM
  Pin Number 53 53
  Pin Name SOM6 SOM6
  Pin Alternate Name SIM_RST SIM_RST
Description Leave unconnected. External SIM support is not available on B-SoM. Leave unconnected, 1.8V/3V SIM Reset Output from cellular modem.
  M.2 connector pin number 69 69
  SoM Common Pin Name SOM6 SOM6

Module Pin 54 (D5)

B-SoM M-SoM
  Pin Number 54 54
  Pin Name D5 D5
  Pin Alternate Name PWM1 PWM1
Description PWM, GPIO D5 D5 GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone D4, D5, and D6 must have the same frequency. Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
I2S interface n/a I2S TX
Internal pull resistance 13K ???
  M.2 connector pin number 68 68
  SoM Common Pin Name PWM1 PWM1

Module Pin 55 (SOM7 / SOM8)

B-SoM M-SoM
  Pin Number 55 55
Pin Name SOM7 SOM8
  Pin Alternate Name SIM_CLK SIM_CLK
Description Leave unconnected, 1.8V/3V SIM Clock Output from R410M. Leave unconnected, 1.8V/3V SIM Clock Output from cellular modem.
  M.2 connector pin number 71 71
  SoM Common Pin Name SOM7 SOM7

Module Pin 56 (D6)

B-SoM M-SoM
  Pin Number 56 56
  Pin Name D6 D6
  Pin Alternate Name PWM2 PWM2
Description PWM, GPIO D6 D6 GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
  Supports analogWrite (PWM) Yes Yes
Supports tone D4, D5, and D6 must have the same frequency. Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
I2S interface n/a I2S CLK
Internal pull resistance 13K ???
  M.2 connector pin number 70 70
  SoM Common Pin Name PWM2 PWM2

Module Pin 57 (SOM8 / SIM_DATA)

B-SoM M-SoM
  Pin Number 57 57
Pin Name SOM8 SIM_DATA
  Pin Alternate Name SIM_DATA SIM_DATA
Description Leave unconnected. External SIM support is not available on B-SoM. Leave unconnected, 1.8V/3V SIM Data I/O of cellular modem with internal 4.7 k pull-up.
  M.2 connector pin number 73 73
  SoM Common Pin Name SOM8 SOM8

Module Pin 58 (D7)

B-SoM M-SoM
  Pin Number 58 58
  Pin Name D7 D7
  Pin Alternate Name PWM3 PWM3
Description PWM, GPIO D7, Blue LED D7 GPIO, PWM
  Supports digitalRead Yes Yes
  Supports digitalWrite Yes Yes
Supports analogWrite (PWM) PWM is shared with the RGB LED, you can specify a different duty cycle but should not change the frequency. Yes
Supports tone No Yes
Supports attachInterrupt Yes. You can only have 8 active interrupt pins. Yes
I2S interface n/a I2S WS
Internal pull resistance 13K ???
  M.2 connector pin number 72 72
  SoM Common Pin Name PWM3 PWM3

Module Pin 59 (GND)

Unchanged between B-SoM and M-SoM
Pin Number 59
Pin Name GND
Description Ground.
M.2 connector pin number 1
SoM Common Pin Name GND

Module Pin 60 (SOM9 / SOM8)

B-SoM M-SoM
  Pin Number 60 60
Pin Name SOM9 SOM8
Pin Alternate Name n/a CELL_RI
Description M.2 pin 75. Not currently used, leave unconnected. CELL_RI, ring indicator output, leave unconnected.
  M.2 connector pin number 75 75
  SoM Common Pin Name SOM9 SOM9

Schematics

To be provided at a later date.


Mechanical specifications

Parameter Value
Operating temperature -20°C to 65°C

Dimensions and weight

To be provided at a later date.

Revision history

Revision Date Author Comments
pre 2024-03-18 RK Initial Release (based on board v0.2 20240315)
2024-03-19 RK USB-C power limitations
2024-04-16 RK Description of TS jumper was backwards
1 2024-05-22 RK Public release
2 2024-05-29 RK Descriptions for labels 1 and 3 were reversed