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Microcontroller
Adafruit Feather M0 Express
The classic Feather M0 with 2 MB SPI flash for CircuitPython.
- GPIO
- I2C
- SPI
- UART
- ADC
- DAC
- PWM
- USB
- Processor
- ATSAMD21G18 Arm Cortex-M0+ @ 48 MHz
- Logic
- 3.3 V GPIONot 5 V tolerant
- Power
- Micro-USB, LiPo connector, 3.3 V rail
- Format
- Feather module
Before you wire
2 cautions- GPIO is 3.3 V only.
- D9 reads the battery voltage through a divider.
Pin map
Connector
Feather 16+12 headers
USB at top, JST battery at top-left, component side up
Simplified technical illustration. Pin data is source-backed; verify against the linked documentation before wiring.
Pin
Hover, tap, or arrow to a pad to inspect it.
- Pad order and nets come from Adafruit's Feather M0 Express board file (JP1, JP3), with GPIO numbers from CircuitPython pins.c.
- GPIO is 3.3 V only and is not 5 V tolerant.
- Left header positions 1-16, right header positions 17-28. A0 doubles as the DAC output.
All 28 pins (table)
| # | Signal | Role | Net | Also / notes |
|---|---|---|---|---|
| 1 | System | |||
| 2 | Power | 3V3 | ||
| 3 | Alt | |||
| 4 | Ground | GND | ||
| 5 | DAC | PA02 | ||
| 6 | ADC | PB08 | ||
| 7 | ADC | PB09 | ||
| 8 | ADC | PA04 | ||
| 9 | ADC | PA05 | ||
| 10 | ADC | PB02 | ||
| 11 | SPI | SPI | PB11 | |
| 12 | SPI | SPI | PB10 | |
| 13 | SPI | SPI | PA12 | |
| 14 | UART | UART | PA11 | |
| 15 | UART | UART | PA10 | |
| 16 | Ground | GND | ||
| 17 | Power | BAT | ||
| 18 | System | |||
| 19 | Power | USB | ||
| 20 | GPIO | PA17 / LED | ||
| 21 | GPIO | PA19 | ||
| 22 | GPIO | PA16 | ||
| 23 | GPIO | PA18 | ||
| 24 | GPIO | PA07 | ||
| 25 | GPIO | PA20 | ||
| 26 | GPIO | PA15 | ||
| 27 | I2C | I2C | PA23 | |
| 28 | I2C | I2C | PA22 |
Source references
Why it matters
- A long-running CircuitPython and Arduino board.
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