Detecting dsp controller type (56F8355 vs 56F8155)

[adicarlo]

We  need to write code that can run either on a 56F8355 or 56F8155 processor. We thought we could use the chip ID information, but apparently the ID is the same for the two processors. Is there another reliable way to detect which processor the code is running on?

[johnlwinters]

No reliable way other than a test of all the extra features of the 355, as there is nothing to prevent them from existing in an untested form in the 155 per the data sheet.

[adicarlo]

Hello John,

thank you for your answer.

1) I assume at this point the 155 to be a cheaper part just because it has lower test coverage.. or possibly at least some failed test in some of the "missing" functional blocks.. Is my assumption correct?

By the way, I missed this being somehow mentioned in the data sheet. Do you remember which section of the document reports this information?

2) Code which we would like to run on both chips is actually just bootloader code. We may have boards with either chip and application FW which can either use xFlash or place everything in pFlash (of course only the latter would apply when running on a 155). What we actually need to know is just whether xFlash is used by the application or not. If we run on a 355 we can test a specific xFlash location for a flag (e.g. 0x55AA) which tells us that xFlash is used.

But, what can we expect when attempting to read xFlash on a 155?

Could a catastrophic failure occur (e.g. freezing or resetting the processor)?

If reading xFlash on a 155  can only either succeed or fail "graciously", then we could still use this method (assuming probability that reading will return 0x55AA just by chance to be low "enough", of course).

Thank you again

[johnlwinters · Accepted solution]

But, what can we expect when attempting to read xFlash on a 155? Could a catastrophic failure occur (e.g. freezing or resetting the processor)?

No catastrophic failure would occur.