topic Re: generate an illigal operation in 8-bit Microcontrollers

generate an illigal operation

admin — Fri, 04 Jun 2010 11:00:04 GMT

Dear All:

i'm now using the 9s08dz32. i want to generate an illigal operation to force the mcu to reset. when in asm, the code looks like this:

ILOP        MACRO      ;
            DC.B    $8d             ; this is illegal operation code
            ENDM        ;

but i don't know how to implement this code into C.

could anyone help me?

Re: generate an illigal operation

bigmac — Fri, 04 Jun 2010 11:50:09 GMT

Hello,

I am not sure whether this can be done with inline assembly?

However, a method that should work would be to create an ASM file to contain the illegal operation code within a sub-routine. The sub-routine would then be called from within the C file (as a function with the same name). A prototype will be needed within the C file, and an XDEF reference within the ASM file.

Perhaps others will be able to provide a simpler method.

Regards,

Mac

Re: generate an illigal operation

admin — Fri, 04 Jun 2010 12:20:34 GMT

could you please explain it in detail, or where can i find the instructions on how to call a sub-routine which is in assembly in C?

sorry for my cross post

Re: generate an illigal operation

peg — Fri, 04 Jun 2010 12:30:57 GMT

Hello,

I think this has been covered before. Search this forum. Maybe include ILOP in search.

It has definately been discussed before but I am not sure on the 'C' details.

Worth a try anyway.

Re: generate an illigal operation

eckhard — Fri, 04 Jun 2010 16:07:11 GMT

Hello,

Fabio Pereira has an example for an ILAD reset on his page.

Look at the Code for chapter 5.

It should be easy to adapt it to ILOP.

The reset function is implemented als follows :

void reset(void)
{
unsigned int temp = 0x9E00;
__asm
{
LDHX @temp // load the address of temp into H:X
JMP ,X // jump to the address pointer to by H:X
}
}

Eckhard

Re: generate an illigal operation

bigmac — Fri, 04 Jun 2010 17:17:53 GMT

Hello,

Maybe the following might work for an ILOP reset.

void reset(void)
{
byte temp = 0x8D;

__asm JMP @temp; // Jump to the illegal opcode
}

Regards,

Mac

Re: generate an illigal operation

CompilerGuru — Fri, 04 Jun 2010 21:58:19 GMT

As it was discussed in the past, there is no need for the jmp.

https://community.freescale.com/message/10910#10910

The HLI supports to embed arbitrary bytes into the instruction stream.

Daniel

Re: generate an illigal operation

Fijvv — Tue, 15 Jun 2010 04:20:28 GMT

I have used:

#define MCU_RESET() asm DCW $9E00

if (Result[Ch]>=24)

MCU_RESET();