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

1. The ATtiny816 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 ATtiny816 just like we did for the ATSAMD09. With the 2021-2022 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:

• ATtiny816 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 8 and 9

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.