Discussion
Have been banging my head against this ATmega1284 problem for a few days now.
Tried programming a bootloader to it with two different arduino boards, but the chip does not respond.
I added an external 16 MHz crystal and two 22pF capacitors to try and get its clock going, but same effect, the chip does not respond to the programmer.
The arduinos can both flash bootloaders to each other, and I tried flashing a spare ATmega328 but that is also unresponsive.
I must be wiring it up wrong somehow.
@dirtycommo this is ancient half remembered and likely unhelpful but
ages ago when i was learning avr microcontrollers, i managed to change its "fuse bits" such that it went similarly non-responsive
i learned that this can be fixed, but only using a special "high voltage" programmer
everyone's advice to me at the time was, that's a lot of work and chips are cheap, just trash it and get another (ugh)
project went on the shelf and haven't picked it back up yet
sortof authoritative info, only useful thing here is clarifying that for your atmega1284 you will be doing "high voltage parallel programming (HVPP)" not these other acronyms i have never used: HVSP, HV TPI, or HV UPDI. mfr tries to make you think you need the programmers they make, but you can diy
https://support.microchip.com/s/article/High-Voltage-Programming-on-AVR-devices
aha finally, this looks like a great info resource that doesn't assume you want to manufacture a whole ass pcb to get the job done
https://microtherion.github.io/ScratchMonkey/HVPP.html
@purple I have messaged the supplier. Some blogs from about a decade ago seem to suggest that blank chips from the factory come set to 8 MHz with their internal oscillator.
So I will try that next.
Install bonfire.cafe
Get the full app experience
after discussions on arcane facebook groups it has been revealed to me that there are ISPs you can plug into the USB port of your computer
https://core-electronics.com.au/usbasp-usbisp-3-3v-5v-avr-programmer.html
if THIS does not work, i will throw every arduino i own out the window and find some other microcontroller platform
open to suggestions, anything 8 bit is acceptable.
#retrocomputing #arduino