JTAG UART repeating characters on Cyclone IV Transciever Kit

Thanks Dave,

I can check that in the debugger...

Would you examine the stack pointer value as the printf progresses ?

I am not familiar with all the debug hooks in Eclipse but for a JTAG debugger I would add a barrier or waypoint at the top of the stack to trap such a nasty event.

However, if there was such a collision I would expect more to go off into the weeds unless all I did was a single printf.

I added the printf to a loop with an count value that I would expect was on the heap and I got the printf called the expected number of times

all with the similar but not identical signature of repeated characters.

To isolate this I really need to redirect the stdio to something apart from the JTAG UART, like a real UART.

If I get the same result then I would say it is something more pervasive.

I have other variables on the heap that control the printf being called so I would expect them to be corrupted by a stack -> heap collision.

I also have a recursion test to load up the stack and I can try running that to see if bad things happen without calling printf.