Datasheet

All the GPIO pads can be used as digital inputs, digital outputs, for LEDs, buttons and switches. In additon, all can be

used as analog inputs (12-bit ADC) or hardware capacitive touch. All pads can also be used as hardware interrupts

inputs.

Each pad can provide up to ~7mA of current. Don't connect a motor or other high-power component directly to the

pins! Instead, use a transistor to power the DC motor on/off (https://adafru.it/aUD)

On a Gemma M0, the GPIO are 3.3V output level, and should not be used with 5V inputs. In general, most 5V devices

are OK with 3.3V output though.

The three pads are completely 'free' pins, they are not used by the USB connection, LEDs, DotStar, etc so you never

have to worry about the USB interface interfering with them when programming

Unique pad capabilities

Pad #0 / A2 - this is connected to PA04 on the ATSAMD21. This pin can be used as a digital I/O with selectable

pullup or pulldown, capacitive touch, analog input (use 'A2'), PWM output, and is also used for I2C data (SDA),

and hardware Serial RX.

Pad #1 / A0 - this is connected to PA02 on the ATSAMD21. This pin can be used as a digital I/O with selectable

pullup or pulldown, capacitive touch, analog input (use 'A0'), and true analog (10-bit DAC) output. It cannot be

used as PWM output.

Pad #2 / A1 - this is connected to PA05 on the ATSAMD21. This pin can be used as a digital I/O with selectable

pullup or pulldown, capacitive touch, analog input (use 'A1'), PWM output, and is also used for I2C clock (SCL),

and hardware Serial TX.

Secret SWD and Reset Pads

On the bottom of the Gemma M0 you will see three small pads. These are used for our programming/test but you can

use them too.