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Differences between batches of Rev H silicon?

Question asked by gaut.michael on Dec 20, 2011

We are using the STR911FAWX6 Rev H device on one of our products that has been in manufacture now for around 2 years.  We have shipped hundreds of these without a problem.

However, on the latest build the CPUs were sourced separately and although they are clearly marked as rev H, they do have different a batch code on them from the previous ones we used.  The problem is, the exact same software fails 100% of the time with this CPU.

I narrowed this down to the routine that writes to FLASH.  We run the software from bank 0 and use bank 1 to store configuration settings and so on.  Our firmware has the ability to erase and reprogram bank 1 as necessary.  With the latest CPUs, if I prevent the software from writing to FLASH, it runs perfectly, but with the write included the CPU falls over in such a state that even with the debugger connected the only option to recover is a hard reset.

So my question is, has anyone else noticed any difference in FMI operation between different batches of the same Rev H device? 

Many thanks