topic Re: Checksum calculation in CodeWarrior for MCU

Checksum calculation

markiscarabas — Sat, 20 May 2006 02:51:12 GMT

Hi,

I need to checksum (crc) the area of read_only memory. I am trying to use the embedded checksum algorithms. My prm file looks like:

NAMES END

SEGMENTS

RAM_BOOT = READ_WRITE 0x2000 TO 0x3FFF;
ROM_BOOT = READ_ONLY 0xF802 TO 0xFCFF FILL 0xFF;
END

PLACEMENT
   DEFAULT_ROM                  INTO ROM_BOOT;
   DEFAULT_RAM                  INTO RAM_BOOT;

END

CHECKSUM
CHECKSUM_ENTRY
METHOD_CRC16 POLY 0x1021 OF READ_ONLY 0xF802 TO 0xFFFF INTO READ_ONLY 0xF800 SIZE 2
UNDEFINED 0xFF
END
END

It looks like everything works OK as soon as I am using the defined in prm file section. The problem here is that I am also using some absolute code positioning and this memory area is not specified in prm file....It looks like the checksum routine does not know what is located at my absolute addresses?!

Re: Checksum calculation

CompilerGuru — Sun, 21 May 2006 20:46:31 GMT

Which version of CW (and more specifically, the linker) are you using?
If not using the latest and greatest already, can you try it?
Can you provide a complete (but as simple as possible), linking sample?
Daniel

Re: Checksum calculation

markiscarabas — Mon, 22 May 2006 23:07:54 GMT

Thanks,

My CW is for HC12 3.1 Build 4047. It will take me some time to create the simple demo code. Linker rev is 5.0.9.0 9/7/2003.

Re: Checksum calculation

CompilerGuru — Tue, 23 May 2006 01:40:54 GMT

In the release notes to the HC12 V4.5, linker version V5.0.29, there are entries which may explain your problem.
As HC12 V4.5 is downloadable from the web, I would suggest that you try it with this version first.

Daniel