CRC checksum

[Hank]

Hello,

I want to use this "prm File-Controlled Checksum Computation" for a QY4 with the freeware CodeWarrior version 5.1 as here described (part of the prm file):

CHECKSUM

  CHECKSUM_ENTRY
  METHOD_CRC_CCITT
  OF READ_ONLY 0xEE20 TO 0xEEFF
  INTO READ_ONLY 0xEE08 SIZE 2
  UNDEFINED 0xFF
 END
END

But it does not manipulate the s19 file.

Is it a problem of the freeware version?

Or are there some additional project settings necessary?

Thanks for answer.

Hank

[CompilerGuru]

No, that is supposed to work with any version regardless of the license.
I created a new QY4 project with the wizard, adapted the generated prm to start at 0xEE20, pasted your snippet into the prm, built it, and decoded the generated project.abs.s19.
Here are the two bytes of the checksum out of the listing file.

Code:

S105EE081BD217Type:     S1 (A record containing the 2-bytes address at which the code/data is to reside)Length:   0x5Address:  0xEE08Data:     0xEE08   1B D2 CheckSum: 0x17

so it basically worked fine for me, I wonder why it did not for you.

 

[Hank]

Thanks for help.

My problem was that the area in which i tried to write the CRC already exists within the s19 file. And this is not possible. That means with this function I cannot patch a existing s19 file.

[CompilerGuru · Accepted solution]

I'm not sure I can follow.
The linker usually writes S19 as one of its output formats, it does not read them (well not in the usual setup at least).

Does your actually aplication already contain some values at 0xEE08?
No, that's not supported. The linker only allows to have one initialized value at one address. You have to eclude that area from the segments in the prm.
If there is something already linked there, then that's just a conflict and not a legal setup.

Daniel