Datasheet

Most pins can do PWM output

All pins can be interrupt inputs

Top Row

#0 / RX - GPIO #0, also receive (input) pin for Serial1 (hardware UART)

#1 / TX - GPIO #1, also transmit (output) pin for Serial1

#2 through #12 - These are general purpose GPIO. If there's a dot next to the pad it can act as a PWM output.

#13 - GPIO #13 and is connected to the red LED marked L next to the USB jack

SDA - the I2C (Wire) data pin. There's no pull up on this pin by default so when using with I2C, you may need a

2.2K-10K pullup.

SCL - the I2C (Wire) clock pin. There's no pull up on this pin by default so when using with I2C, you may need a

2.2K-10K pullup.

Bottom Row

A0 - This pin is analog

input

A0 but is also an analog

output

due to having a DAC (digital-to-analog converter).

You can set the raw voltage to anything from 0 to 3.3V, unlike PWM outputs this is a true analog output

A1 thru A5 - These are each analog input as well as digital I/O pins.

Right side

SCK/MOSI/MISO - These are the hardware SPI pins, are are connected to the 2x3 header on the right hand side.

you can use them as everyday GPIO pins (but recommend keeping them free as they are best used for hardware

SPI connections for high speed.)

Additional analog inputs

In addition to the A0-A5 pins, there are extra analog inputs available

Digital #0 is also A6

Digital #1 is also A7

Digital #4 is also A8

Digital #5 is also A9

Digital #8 is also A10

Digital #9 is also A11

These pins are available in CircuitPython under the board module. Names that start with # are prefixed with D and

other names are as is. So #0 / RX above is available as board.D0 and board.RX for example.

SPI Flash and NeoPixel

As part of the 'Express' series of boards, the Metro M0 Express is designed for use with CircuitPython. To make that

easy, we have added two extra parts to this Metro M0: a mini NeoPixel (RGB LED) and a 2 MB SPI Flash chip