TMS320C6657: Processor Initialization issue

Hi

I am running a C6657 at 1.25Ghz with an input clock of 100Mhz

Occasional the GOSTAT bit will never return ok when setting up PLL1. Sometimes the processor will lockup when setting PLL2 ENSAT

The problem happens as follows:

I power on, run the C6657 Gel global_default_init with PPL1_M = 24 and PLL1_D = 0 (100Mhz input -> 1250Mhz core)

If this is successful I can load my application and run without any problems for days. If I reset the processor with the debugger and run global_default_init there is a chance it will get stuck on the GOSTAT or ENSAT as described above. Sometimes I can reset, re-init and run many times before it occurs.

The failure occurs more often at lower temperatures. At 0C there is about a 50% chance of failure on reset.

We have tried this on a number of random boards and while they all fail at 0C they have different failure rates.

We tried increasing all the delays in the gel file by a factor of 1000 but that has no effect on the failure rate.

Please let us know if you have an suggestions on what is causing this issue.

Thanks

Dhar