ColdFire/68K Microcontrollers and Processors中的主题 Re: Exception handling

Exception handling

pass — Wed, 28 Jun 2006 12:43:46 GMT

Hi,

i am working on mcf5282, and i am tring to implement the exception for NULL pointer assignment using chip select module,

can anybody suggest me what is the other way to implement it,

thanx,

Re: Exception handling

mvincent — Thu, 29 Jun 2006 01:01:45 GMT

You could move your ram and flash (internal and external) and IO's out of the bottom of the memory space and then assign an unused chip select to zero, with write protect (read-only). You could also do it with an unused ACRx (cache controller). Null-pointer assigment would result in an access error exception (interrupt vector 2) in both cases. If you also want to trap null pointer de-referencing, don't assign any chip select to the zero range.

Re: Exception handling

mvincent — Thu, 29 Jun 2006 01:06:17 GMT

I think you can also program the BDM to trap an access to a specific memory location, but this might interfere with BDM debugging.