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mc9s12xdt256 & Paged RAM

Eric_t — Thu, 13 Jun 2013 12:12:24 GMT

Hi,

Currently I am working with mc9s12dg256 controller.

Now I have to migrate to mc9s12xdt256AA controller but I have a problem with the paged RAM.

The RAM area of mc9s12dg256 (12KB) is not paged and firmware uses large RAM areas for memory allocation.

The problem is with RAM paged memory of mc9s12xdt256AA, that is 8KB unpaged and two pages of 4KB.

Since my firmware handles the RAM area as one piece, migration to new controller is really painful procedure.

Does anyone know if there is a way for codewarrior to handle the RAM of mc9s12xdt256AA controller as one piece.

Thank you

Nikos

kef — Thu, 13 Jun 2013 13:59:35 GMT

There's no gap between paged RAM and nonpaged RAM. So you may edit XD256 PRM file and redefine RAM segment to include RAM page window like this

RAM = READ_WRITE DATA_NEAR 0x1000 TO 0x3FFF;

RAM_FC = READ_WRITE DATA_FAR 0xFC1800 TO 0xFC1FFF;

/* Undefine RAM_FD. It is used in RAM segment 0x1000..0x1FFF*/

/* RAM_FD = READ_WRITE DATA_FAR 0xFD1000 TO 0xFD1FFF;*/

PAGED_RAM INTO /* when using banked addressing for variable data, make sure to specify

the option -D__FAR_DATA on the compiler command line */

RAM_FC /*, remove RAM_FD*/;

Message was edited by: Edward Karpicz

Eric_t — Mon, 24 Jun 2013 17:06:31 GMT

Thanks Kef.

I have tried it and it works.

Thanks again.