topic Re: how to write code in a specific address using C? in CodeWarrior for MCU

how to write code in a specific address using C?

ffogg — Wed, 18 Nov 2009 08:25:09 GMT

hello there,

i'm programming the MC9S08QG8 chip with Codewarrior v6.2 and using the C compiler.

I need to program a piece of program above address 0xF600 when the program begins

at address 0xE000 and ends at 0xE430 and now i must add some more routines starting

in 0xF600 (a little BIOS) any chance? And of course using 'C'

Thanks in advance.

Re: how to write code in a specific address using C?

bigmac — Wed, 18 Nov 2009 12:23:55 GMT

Hello, and welcome to the forum.

You would need to modify the PRM file for the project, to create a new segment starting at 0xF600.

NAMES END

SEGMENTS

    Z_RAM = READ_WRITE   0x0060 TO 0x00FF;
    RAM    = READ_WRITE   0x0100 TO 0x025F;
    ROM    = READ_ONLY    0xE000 TO 0xF5FF;

HIROM = READ_ONLY 0xF600 TO 0xFFAD;

ROM1 = READ_ONLY 0xFFC0 TO 0xFFCF;
END

PLACEMENT

_DATA_ZEROPAGE,

    MY_ZEROPAGE            INTO Z_RAM;
    DEFAULT_RAM            INTO RAM;

    _PRESTART,             /* startup code */
    STARTUP,               /* startup data structures */
    ROM_VAR,               /* constant variables */
    STRINGS,               /* string literals */
    VIRTUAL_TABLE_SEGMENT, /* C++ virtual table segment */
    DEFAULT_ROM,
    COPY                   INTO ROM;

BIOS_ROM INTO HIROM
END

STACKSIZE 0x50
VECTOR 0 _Startup

Then preceeding the functions required for the BIOS, you will need to use an appropriate #pragma so that the linker to places the code within the BIOS_ROM segment, rather than the DEFAULT_ROM segment.

Regards,

Mac

Re: how to write code in a specific address using C?

ffogg — Thu, 19 Nov 2009 04:11:37 GMT

thanks mac, for your fast and well explained answer

tomorrow if everything is Ok i will try your solution.

I will comment you the final result.

Thanks again and have a good time.

Re: how to write code in a specific address using C?

ffogg — Mon, 23 Nov 2009 06:09:14 GMT

thanks once more, it worked fine.