My first use of a mega1284p
DIP 40 pin, plugs into socket.
Worked fine on first use - programming it with an Atmel MK-II ISCP.
Then I did the deed. Apparently chose the wrong oscillator mode and made the fuse change. Dead now... no read signature response.
What I've tried
The board (old PRLLC board) has an oscillator module. Not a crystal or resonator.
Per my 'scope, it's placing a 6MHz square wave on mega1284's pin 13. I also have a 16MHz one. Neither worked.
Unplugged the oscillator.
Connected a 1MHz square wave so it gets to pin13 of the chip.
I jumpered pin 12 and 13 together. Nothing.
Resets, power cycles, reset ISCB (USB). OK.
Replaced mega1284 with mega32 - same pinout - ISCP sees it fine.
Replaced mega1284 #1 with a new factory fresh mega1284 #2. Reads fine. Graphic enclosed show factory default fuses for #2.
How can I rescue 1284 #1?
I read the mega32's fuse settings and have them, and they are
SUT_CKSEL: EXTHIFXTALRES_1KCK_0MS which is not what I had chosen, but would it work for the mega1284?
Mega1284 #2 factory default includes CKDIV8 checked. I have to look up what that means and should be for changing the fuses to use the 16MHz oscillator module.
Thanks in advance.
I dare not program fuses in #2, as it's the only other one I have now.