All You Ever Needed To Know About UPDI, And Then Some!

This entry is part 1 of 1 in the series IMPLEMENTING UPDI FROM SCRATCH

Part I — Foundations, Electrical Interface, Protocol, and High-Voltage Activation There was a time when connecting a programmer to an AVR microcontroller could consume a surprisingly large number of pins. Traditional AVR In-System Programming used SPI-like signaling. JTAG used four principal signaling wires plus reset and power references. DebugWIRE reduced debugging to essentially one signal,