Hardware I2C / SPI capability for breakout & sensor interfacing. The 2 shared I/O pins have 2 more analogue inputs and one more PWM output. The 3 independent I/O pins have 1 analogue input and 2 PWM output as well. On-board green power LED and red pin #1 LED - Reset button for entering the bootloader or restarting the program - 5 GPIO pins - 2 shared with the USB interface. Up to 16 V input, reverse-polarity protection, thermal and current-limit protection. Whats on board? - Dimensions: 27 x 15 x 4 mm - ATtiny85 on-board, 8K of flash, 512 bytes of SRAM, 512 bytes of EEPROM - Internal oscillator runs at 8 MHz, but can be doubled in software for 16 MHz (only with 5 V version) - USB bootloader with LED indicator - Micro-USB jack for power and/or USB uploading - Roughly 5.25K bytes available for use (2.75K taken for the bootloader) - On-board 3.3 V or 5.0 V power regulator with 150 mA output capability and ultra-low dropout. You cannot stack an Arduino shield on it but for many simple, small, portable or wearable projects, the Trinket could be the perfect platform. This development board is cost effective and provides easy and simple access to the ATtiny85 processor for development and programming.

There is a USB bootloader so you can plug it into any computer and reprogram just like an Arduino. (measures 27 x 15 x 4 mm) The Trinket development kits feature the Atmel ATtiny85 processor with 8K of flash and 5 I/O pins.

The Adafruit Trinket development board is now in its second iteration with even more power packed into a board roughly the size of a postage stamp. Product Details Adafruit Trinket Mini Microcontrollers

Adafruit trinket 5v board programmer