S12 / MagniV Microcontrollers中的主题 Re: Invalid_BP when changing to internal RAM

Invalid_BP when changing to internal RAM

JamesPev — Tue, 15 Aug 2006 22:48:34 GMT

I've been developing an application on the HCS12NE64 eval board. It was running fine using the external memory on that board (the default PRM does not use the 0x2000-0x3FFF internal memory, only 0x400 to 0x1FFF which is mapped to external ram). My application hardware does not have any external ram, so I changed the PRM file to map to internal memory. It compiles/links fine, but when I run the debugger it halts part way through the startup code (specifically in the zero initialization phase) with a "INVALID_BP".

I'm not sure what is happening here. Comparing the .map's from the two different builds shows the only differences being the change in RAM address.

Any ideas?

Thanks!

James

Re: Invalid_BP when changing to internal RAM

JamesPev — Wed, 16 Aug 2006 01:17:56 GMT

I have discovered that the issue only occurs when the stack is moved to the internal RAM. If I leave the stack in the external ram but move everything else it still operates correctly.

I'm pretty confused as to why this is happening. Any ideas would be greaty appreciated.

James

Re: Invalid_BP when changing to internal RAM

CompilerGuru — Wed, 16 Aug 2006 03:05:59 GMT

Where do you set the INITRM register?
It has to be set before the call to Init, otherwise Init wont return as its return address is on the stack.

Daniel

Re: Invalid_BP when changing to internal RAM

JamesPev — Tue, 29 Aug 2006 01:27:01 GMT

The way the initialization files were setup one of the entry point initialization functions was getting bypassed and causing the issue. I believe it was the INITRM register that was the main problem.

James