This breakout board is a "three in one" product:

1. The ATtiny817 is part of the 'next gen' of AVR microcontrollers, and now we have a cute development/breakout board for it, with just enough hardware to get the chip up and running.
2. It's also an Adafruit seesaw board. Adafruit seesaw is a near-universal converter framework which allows you to add and extend hardware support to any I2C-capable microcontroller or microcomputer. Instead of getting separate I2C GPIO expanders, ADCs, PWM drivers, etc, seesaw can be configured to give a wide range of capabilities.
3. Finally, with STEMMA QT connectors on it, you could use it as either an I2C controller or peripheral with plug-and play support.

We primarily designed this board for our own use: it's a mini dev board that lets us design with the ATtiny817 just like we did for the ATSAMD09. With the 2021 silicon shortage, we're adapting some of our SAMD09 designs to the ATTiny8xx series and wanted a quick minimal board to test code on.

Each breakout comes with the assembled and tested board, as well as some header strips. Each PCB is fairly minimal and contains:

• ATtiny817 8-bit microcontroller
  • 8KB flash, 512 bytes of RAM, 128 bytes of EEPROM
  • Internal oscillator can run up to 20MHz
  • Internal hardware multiplier
  • Can run from 2V to 5V power/logic (check the datasheet for max speed at desired power)
• 3.3V regulator - by default we run at the Vin voltage, which can be 5V, but there's a solder jumper on the bottom if you'd like to select 3V logic.
• Green power LED
• Red indicator LED
• Two STEMMA QT I2C connectors with 10K pullup resistors, connected to pins 10 and 11

This board comes pre-programmed with seesaw peripheral code that will let it act as an "I2C to something" converter, basically a little I2C-controlled friend to do all the timing-sensitive things many microcontrollers and microcomputers are not good at.