Strange ICTRL related behaviour on Axiom CME555@40MHz

Hi all,

I'm having problems with an Axiom CME555 board, running at 40MHz 
(MF=9), with ICTRL set to 0x7 (for no serialization and no show 
cycles).   

When I debug the code in CodeWarrior (running from external RAM) I 
occasionally see an "Instruction Storage Exception".   Other times 
when I stop the debugger the program counter is pointing at locations 
in internal flash.

I've found that:

Running at 40MHz with ICTRL = 0x0 (Axiom)  => no problem
Running at 20MHz with ICTRL = 0x7 (Axiom)  => no problem
Running at 40MHz with ICTRL = 0x7 (Axiom)  => failure
Running at 40MHz with ICTRL = 0x7 (Phytec) => no problem

Originally I was working with some complex code that was hooked up to 
the external interrupt (PIT).   However, I've now reproduced the 
failure using just the standard CodeWarrior Axiom 555 example (main.c 
shown below).   

In the default configuration for that example ICTRL is set to 0x0 and 
everything work ok; after continuing on from the system call I stop 
the debugger and it's in the while loop.   If however, I set ICTRL to 
0x7 then after continuing on from the system call the program counter 
is off somewhere unexpected in memory.

Any ideas / suggestions?

Thanks,

Jon.

------------------------------------

Example Project:

void main()
{
	int i=0;
	
	printf("Welcome to CodeWarrior!\r\n");

	system_call(); // generate a system call exception to 
demonstrate the ISR
		
	while (1) { i++; } // loop forever
}






-----------------------------------------------------------
To learn more about Freescale Microcontrollers, please visit
http://www.freescale.com/mcu


 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/MPC500/

<*> To unsubscribe from this group, send an email to:
    [email protected]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/