How to Build a USBtinyISP: Low-Cost DIY AVR Programmer
Atmel AVR chips power a lot of hobby and embedded projects, small, cheap, well-documented. To get code onto them you …
A short follow-up to How to Build a USBtinyISP. The original post covers the build; these are two things I end up doing often enough to write down.
For anything fuse-related, the authoritative reference is the ATtiny2313 datasheet from Microchip; don’t take anecdotal values from the internet at face value.
Before you change fuses, dump what’s actually on the chip:
1avrdude -c usbasp -p t2313 \
2 -U hfuse:r:-:h \
3 -U lfuse:r:-:h
:r:-:h means read, output to stdout, format as hex. The ATtiny2313 has two fuse bytes, low and high.
If plugging in the freshly-built USBtinyISP produces nothing (no entry in lsusb on Linux, no device popup on Windows), walk this list:
1# Back up the full flash of a working board before touching fuses.
2avrdude -c usbtiny -p t2313 -U flash:r:backup.hex:i
For everything else, the Adafruit USBtinyISP guide is a good second reference.