Illegal BP error MC9S08

[b_rad]

Hi,

I'm implementing SPI communications using the MC9S08GT16A. The code has been working perfectly for ages and now, all of a sudden, im getting an illegal BP error.

I keep getting the error even with the watchdog disabled and no interrupts present in my code.

If its not an unmapped interrupt or the watchdog then the other two options are an illegal address or a stack overflow, right?

Ive made the stack as large as possible.

So, how do I check if its trying to access an illegal address, and if so, fix that?

Thanks

[bigmac]

Hello,

Do you happen to be using full chip simulation (FCS) mode?  If so, the SPI code may not operate as intended.  Best to use the actual hardware when testing your SPI code.

Regards,

Mac

[rocco]

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b-rad wrote:

If its not an unmapped interrupt or the watchdog then the other two options are an illegal address or a stack overflow, right?

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There are other things that can cause that problem, like mis-jumping to an address that does not contain valid code, or jumping to valid code but not aligned correctly to the instruction. If your using C, check for un-initialized pointers. In assembler, there are dozens of things that can cause that. I think I've done most of them.