Miniature AVR development board with USB
This is a small AVR development board, a clone of the popular DigiSpark.
The design uses the inexpensive ATtiny85 microcontroller with just the barely minimum external parts that are necessary for the USB communication. The chip is powered by the USB 5V line through two diodes in series which brings the supply voltage down to 3.6 V.
The actual size of the two-layer pcb is only 11 by 25 millimeters with the thickness of 1.6 mm so it fits perfectly inside the metal housing of a USB plug.
After soldering the parts, the Micronucleus bootloader must be uploaded to the AVR using an SO-8 programming clip. After that, the board can be programmed via USB. Three pins (PB0:2) and GND are accessible on the board.
Description
A miniature AVR devboard with USB.