Adafruit Trinket - Mini Microcontroller - 3.3V Logic
Deprecated 3.3V mini microcontroller using bit-bang USB. No longer recommended due to modern USB compatibility issues; Trinket M0 is the current replacement with native USB.
Deprecated 3.3V mini microcontroller using bit-bang USB. No longer recommended due to modern USB compatibility issues; Trinket M0 is the current replacement with native USB.
Battery or external positive input. Adafruit states BAT+ is the Battery + Input pin for a battery, power adapter, solar panel, or other source, reverse-polarity protected.
USB 5V output, present only when Trinket is plugged into the Mini-B USB connector; can be used for USB power sensing or higher-current USB-powered loads.
Common ground for logic and power, connected to USB ground and the regulator.
Digital input/output; PWM output; I2C data; SPI data input.
Digital input/output; PWM output; SPI data output; connected to the onboard LED.
Digital input/output; analogue input A1; I2C clock; SPI clock.
Digital input/output with caution; USB programming pin; analogue input A3; has a 1.5K pullup to 3.3V for USB communications.
Digital input/output with caution; USB programming pin; PWM output; analogue input A2.
Reset pin connected directly to the ATtiny85 reset pin and reset button; used to enter bootloader or reset the board, not a GPIO.
3.3V regulator output from onboard regulator. Adafruit says the regulator output pin is about 3.3V on a 3V Trinket and 5V on a 5V Trinket, up to 150mA.
| Pin | Type | Function | Voltage |
|---|---|---|---|
| BAT+ | Power | Battery or external positive input. Adafruit states BAT+ is the Battery + Input pin for a battery, power adapter, solar panel, or other source, reverse-polarity protected. | Up to 16V DC; for 3V Trinket use at least 3.5V input, for 5V Trinket 5.5V or higher suggested. |
| USB+ | Power | USB 5V output, present only when Trinket is plugged into the Mini-B USB connector; can be used for USB power sensing or higher-current USB-powered loads. | 5V from USB, Adafruit notes 500mA+ available from USB ports. |
| GND | Ground | Common ground for logic and power, connected to USB ground and the regulator. | 0V |
| GPIO #0PB0 | GPIO | Digital input/output; PWM output; I2C data; SPI data input. | 3.3V GPIO output level; Adafruit warns not to use with 5V inputs. |
| GPIO #1PB1 | GPIO | Digital input/output; PWM output; SPI data output; connected to the onboard LED. | 3.3V GPIO output level; Adafruit warns not to use with 5V inputs. |
| GPIO #2PB2A1 | GPIO, Analog | Digital input/output; analogue input A1; I2C clock; SPI clock. | 3.3V GPIO output level; Adafruit warns not to use with 5V inputs. |
| GPIO #3PB3A3 | GPIO, Analog | Digital input/output with caution; USB programming pin; analogue input A3; has a 1.5K pullup to 3.3V for USB communications. | 3.3V GPIO output level; Adafruit warns not to use with 5V inputs. |
| GPIO #4PB4A2 | GPIO, Analog | Digital input/output with caution; USB programming pin; PWM output; analogue input A2. | 3.3V GPIO output level; Adafruit warns not to use with 5V inputs. |
| RST | Control | Reset pin connected directly to the ATtiny85 reset pin and reset button; used to enter bootloader or reset the board, not a GPIO. | |
| 3V | Power | 3.3V regulator output from onboard regulator. Adafruit says the regulator output pin is about 3.3V on a 3V Trinket and 5V on a 5V Trinket, up to 150mA. | 3.3V, up to 150mA |
Battery or external positive input. Adafruit states BAT+ is the Battery + Input pin for a battery, power adapter, solar panel, or other source, reverse-polarity protected.
USB 5V output, present only when Trinket is plugged into the Mini-B USB connector; can be used for USB power sensing or higher-current USB-powered loads.
Common ground for logic and power, connected to USB ground and the regulator.
Digital input/output; PWM output; I2C data; SPI data input.
Digital input/output; PWM output; SPI data output; connected to the onboard LED.
Digital input/output; analogue input A1; I2C clock; SPI clock.
Digital input/output with caution; USB programming pin; analogue input A3; has a 1.5K pullup to 3.3V for USB communications.
Digital input/output with caution; USB programming pin; PWM output; analogue input A2.
Reset pin connected directly to the ATtiny85 reset pin and reset button; used to enter bootloader or reset the board, not a GPIO.
3.3V regulator output from onboard regulator. Adafruit says the regulator output pin is about 3.3V on a 3V Trinket and 5V on a 5V Trinket, up to 150mA.
USB · 3.3 V
Confirm the data interface matches your host board.
Module pins: BAT+, USB+, 3V, GND, GPIO #0 / PB0, GPIO #1 / PB1, GPIO #2 / PB2 / A1, GPIO #3 / PB3 / A3. Schematik maps them to your board in the app.
Specialists: Teensy for high-clock audio and USB, Adafruit SAMD boards running CircuitPython or the Arduino IDE, proper STM32 eval kits, and the micro:bit classroom ecosystem. Schematik builds target ESP32, Arduino Uno, and Pico; come here when you have a specific reason to.
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