I have implemented the 64 bit version of the time stamp counter in my code. When the code does not access the time stamp counter for longer than it takes to have the lower 32 bits roll over the upper 32 bits appears to only be incremented only once. I am testing on the EVM3359 board running at 550Mhz.. This should increment the high 32 bit register about once every 7.8 seconds. If I set a task to sleep for 2 seconds at a time and read the counter every thing is fine. If the task sleeps for longer than the 7.8 seconds time disappears. I have changed the code to sleep only 2 seconds but only access the counter once every 16 seconds and the time is incorrect so it doesn't appear to have anything to do with the task sleep and only has to do with the time for the last access.
Any help would be appreciated.