Datasheet

Power Pins

We'll start with the top pins BAT+, GND, USB+, and 3V or 5V

BAT+ is the Battery + Input pin. If you want to power the Pro Trinket from a battery or power adapter or solar

panel or any other kind of power source, connect the + (positive) pin here! You can connect up to 16V DC. If you

have a 3V Pro Trinket, you'll want at least 3.5V input to get a good 3.3V output. If you have a 5V Pro Trinket,

5.5V or higher is suggested. This input is reverse-polarity protected.

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

BUS is the USB Bus + Output pin. If you want to use the USB 5V power for something, like charging a battery, or

if you need more than 150mA of current (this pin can supply 500mA+ from USB ports) or to detect when the Pro

Trinket is plugged into USB, this pin will have 5V power on it if and only if its plugged into something via the

micro B connector. Don't put power into this pin, that's what BAT+ is for - use it only as an output!

The next pin is either 3V or 5V depending on which Trinket Pro you have. It is the output of the low dropout regulator.

The regulator is powered by either BUS or BAT (whichever is higher!) It will automatically switch between the two if

USB or battery is removed using two schottky diodes. There is a 0.2V dropout due to the diode and maybe 50-100mV

minimum drop in the regulator.

The regulator can supply approximately 150mA as long as it doesnt overheat. Make sure that you keep BAT+ low to

minimize heat-loss! About 1 or 2 Volts higher than 3V or 5V is ideal.

GPIO Pins

Next we will cover the 18 GPIO (General Purpose Input Ouput) pins! 18 GPIO is a big step up from the little Trinket with

only 5 or so pins. This is almost as many as a 'full grown' Arduino. In fact, since the Pro Trinket uses the same core chip

as an Arduino, nearly any existing project that uses special pins like hardware PWM or SPI will work 'out of the box'.

All the GPIO pins can be used as digital inputs, digital outputs, for LEDs, buttons and switches etc. They can provide up

to 20mA 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

Logic Level

On a 3V Pro Trinket, the GPIO are 3.3V output level, and should not be used with 5V inputs. On a 5V Pro Trinket, the

GPIO are 5V output level, and can be used with 3V inputs but may damage electronic devices that are 3V input only!