I'm working on a project where I use m16, m324 and m644. Our customer bought a lot (ca 5000) atmega1284(not P) and of course wants us to use them.
The issue is that code that runs fine on the other processors crash (freeze or go extremely slow) on the m1284. Everything (SPI, timers etc.) works fine until we send data to the UART. The problems occur even if the UART is disabled and the RX0 pin tristated.
The current design has been produced in tens of thousands without any problem on m644.
I and my colleagues have been scrathing our heads for days now and are starting wonder if there is a silicon error. Or is the m1284 just more sensitive to something not mentioned in the datasheets?
We'll meet an Atmel sales representative tomorrow, but I'm thankful for any hint or help.