I have a board built around a ATMEGA128RFA1. One of the UARTs is translated by a MAX3250, and monitored by a PC. Because it is a 128RFA1, I have an external 16MHz crystal (fuses appropriately configured).
For the last week, the UART has been functioning perfectly normally (i.e., printing characters and accepting characters without any problems).
After my last hex download, it went [partially] haywire.
I have attached a screen shot of my terminal program. Note, my firmware is talking to another device, and periodically prints out what the MCU is going to transmit, as well as any data received from the other device, parsed into human readable format.
What is odd is that their appears to be some sort of "substitution" going on. I.e., I don't believe that it is bit errors, or it wouldn't be consistent (i.e.
Has anyone ever seen something like this? I am not including code in this post because I don't want somebody to "solve" the problem. I understand bit errors, buffer overruns, etc., but not a random substitution of [relatively appropriate] Greek letters.