{"title":"Adafruit ATtiny817 Breakout with seesaw - STEMMA QT / Qwiic","handle":"adafruit-attiny817-breakout-with-seesaw-stemma-qt-qwiic","url":"/products/adafruit-attiny817-breakout-with-seesaw-stemma-qt-qwiic","description":"The Adafruit ATtiny817 Breakout with seesaw is a compact development board that combines an ATtiny817 microcontroller with the Adafruit seesaw I2C framework and STEMMA QT connectivity. Pre-programmed with seesaw firmware, it acts as an I2C-controlled co-processor — adding GPIO, ADC, PWM, and NeoPixel support to any I2C-capable host.\n\nThis board can also be reprogrammed as a general-purpose ATtiny817 development board using the megaTinyCore Arduino core. With STEMMA QT connectors, it works seamlessly as either an I2C controller or peripheral with plug-and-play support.\n\nKey Features\n\n\nATtiny817 Microcontroller – 8KB flash, 512 bytes RAM, 128 bytes EEPROM, internal oscillator up to 20 MHz, hardware multiplier\n\nSeesaw I2C Framework – Universal converter providing GPIO, ADC, PWM, and NeoPixel control over I2C\n\n14× GPIO – With selectable pullup resistors\n\n9× 10-bit ADC Inputs – Pins 0, 1, 2, 3, 6, 7, 18, 19, 20\n\n5× 8-bit PWM Outputs – Pins 0, 1, 9, 12, 13\n\nNeoPixel Output – Drive up to 60 NeoPixel LEDs from a single pin\n\n127-byte EEPROM – Non-volatile memory for tokens or MAC addresses (last byte used for I2C address)\n\nInterrupt Output – Pin 15, triggered by any configured peripheral\n\n2× I2C Address Selection Pins – Pins 16 and 17 for running multiple boards on one bus\n\n2× STEMMA QT / Qwiic Connectors – Plug-and-play I2C with 10K pullup resistors (pins 10, 11)\n\n3.3V Regulator – Runs at Vin by default (up to 5V); solder jumper to select 3.3V logic\n\n2V to 5V Operation – Wide voltage range for flexible integration\n\nPower and Activity LEDs – Green power LED, red indicator LED on pin 5\n\n\nAlso Available\n\n\nATtiny1616 Seesaw Breakout with STEMMA QT – More memory (16KB flash, 2KB RAM) and up to 250 NeoPixels\n\nATtiny816 Seesaw Breakout with STEMMA QT – Same memory, different pin mapping\n\nATSAMD09 Seesaw Breakout – Original seesaw breakout with ARM Cortex-M0+\n\n\nIdeal For\n\nAdding extra I/O to Raspberry Pi, ESP32, or Arduino projects via I2C\nNeoPixel control from I2C-only platforms\nATtiny817 development and prototyping\nSeesaw firmware customisation and testing\n\n\nPackage Contents\n\n1× Adafruit ATtiny817 Breakout with seesaw\n1× Header strip set\n\n\n\nNote: This board does not include a bootloader. To reprogramme or customise the seesaw firmware, you will need a UPDI programmer (which can be made from a USB-to-serial cable and a single 4.7K or 10K resistor). The firmware is compiled using megaTinyCore. No support is provided for custom seesaw builds.\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":2988,"title":"Default Title","sku":"AF-5233","price":10.11,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":16,"option1":"Default Title"}]}