kscharf wrote:The atmega1284 and atmega1284P spec sheets show a max voltage rating of 6 volts, though the "safe operating" area shows up to 5.5 volts. It is common knowledge among PC overclockers that increased core voltage is sometimes required to get a processor to overclock well. Have you tried increasing the power supply voltage to the ATmega1284P? You should try up to 6 volts and see if it then works. Also look for a 40 pin slip on heatsink for the processor. If you can't find one just slap a hunk of metal on top of the chip with superglue. Also you might need to use an external oscillator instead of relying on the processor to clock it's own crystal. You might be able to force the atmega1284p to work yet!
These are interesting ideas. This comes with it's own problems unfortunately. Raising the voltage would imply changing the regulator, the video DAC and voltage interfaces to other chips like the SD card. I don't think heat would we an issue as even overclocked the the chip stays cool. An external clock, although much more expensive, could be an idea to try. If anyone else wants to try the suggested ideas, be my guest. To make it simple, the basic B/W design could be used as a PoC. Personally, I won't have time to fiddle more on this until a couple months.