Datasheet

3V - This is the 3.3V OUTPUT pad from the voltage regulator. It can provide up to 500mA at a steady 3.3V. Good

for sensors or small LEDs or other 3V devices.

GND is the common ground pin, used for logic and power. It is connected to the USB ground and the power

regulator, etc. This is the pin you'll want to use for any and all ground connections

Input/Output Pins

Next we will cover the 5 GPIO (General Purpose Input Ouput) pins! For reference you may want to also check out the

datasheet-reference in the downloads section for the core ATSAMD21E18 pin. We picked pins that have

a lot

capabilities.

Common to all pads

All the GPIO pads can be used as digital inputs, digital outputs, for LEDs, buttons and switches. 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 Trinket 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 five pins 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

Digital #0 / A2 - this is connected to PA08 on the ATSAMD21. This pin can be used as a digital I/O with

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

Digital #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.

Digital #2 / A1 - this is connected to PA09 on the ATSAMD21. This pin can be used as a digital I/O with

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

hardware SPI MISO

Digital #3 / A3 - this is connected to PA07 on the ATSAMD21. This pin can be used as a digital I/O with

selectable pullup or pulldown, analog input (use 'A3'), capacitive touch, PWM output, and is also used for UART

RX (Serial1 in Arduino), and hardware SPI SCK

Digital #4 / A4 - this is connected to PA06 on the ATSAMD21. This pin can be used as a digital I/O with

selectable pullup or pulldown, analog input (use 'A4'), capacitive touch, PWM output, and is also used for UART

TX (Serial1 in Arduino), and hardware SPI MOSI

Other Pads!

Digital #7 - You can't see this pin but it is connected to the internal RGB DotStar data in pin

Digital #8 - You can't see this pin but it is connected to the internal RGB DotStar clock in pin

Secret SWD Pads

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

use them too.