There are two versions of the Pro Trinket: 3V and 5V. They are not available for use and are not broken out. That's because we use those two pins for the USB bootloader. If you're used to using an Arduino Uno, you may notice that pins #2 and #7 are not available. These pins cannot be used for LEDs, buttons, servos, etc. They're kind of an 'extra' that you get with the Pro Trinket. The two pins that sit sort-of inside the body of the Pro Trinket, A6 and A7, are analog input only pins.

Analog 5 - also known as Digital 19, this pin can be a digital I/O pin or an analog input pin.

Analog 4 - also known as Digital 18, this pin can be a digital I/O pin or an analog input pin.Analog 3 - also known as Digital 17, this pin can be a digital I/O pin or an analog input pin.Analog 2 - also known as Digital 16, this pin can be a digital I/O pin or an analog input pin.Analog 1 - also known as Digital 15, this pin can be a digital I/O pin or an analog input pin.Analog 0 - also known as Digital 14, this pin can be a digital I/O pin or an analog input pin.Digital 12 - Also known as the SPI MISO pinDigital 13 - Also known as the SPI CLOCK pin.this pin can also be used as a PWM output pin using analogWrite() Digital 11 - Also known as the SPI MOSI pin.Digital 10 - this pin can also be used as a PWM output pin using analogWrite() It's also good for driving servos because its a high-speed PWM output.

Digital 9 - this pin can also be used as a PWM output pin using analogWrite() It's also good for driving servos because its a high-speed PWM output.Digital 8 - Nothing particularly special about this GPIO pin.

Digital 6 - this pin can also be used as a PWM output pin using analogWrite().

Digital 5 - this pin can also be used as a PWM output pin using analogWrite().

Digital 4 - Nothing particularly special about this GPIO pin.

Digital 3 - this pin can also be used as a PWM output pin using analogWrite().

TX - also known as Digital #1, this is the hardware serial output pin.

RX - also known as Digital #0, this is the hardware serial input pin.

Adafruit trinket 5v starting