Marc Paquette

CodeWarrior 8- & 16-bit tools: External RAM 68HC912DG128A

Discussion created by Marc Paquette Employee on Jan 27, 2006
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Posted: Jul 27, 2004 - 07:50 AM   

Hi,

Does someone know how I can add external ram on my motorola? I have found 1 electrical schematic, but I don't know how to do the soft. 
I have defined the adresse of my external RAM in the prm (code Warrior 3.1) from 68000 to 6BFFF

( Ram_externe = READ_WRITE 0x68000 TO 0x6BFFF;
DEFAULT_RAM INTO RAM, Ram_externe:smileywink:

and in my main, I have initialized my register :

MISC=0b00001110;
MODE=0b01111011;
PEAR=0b00101100;

And to see if I have access to my external RAM when my internal RAM is full I have made an array of 5000 caracters.

unsigned int far i;
unsigned int far tab[5000];

for (i=0; i<5000; i++)
{
tab[i]=0xFFCC;
}

So when I compile I have always got the same warning:
L1128: Cutting value StackOffset Startup data member from 0x6A80F to A80F.

And then it doesn't works.

Does someone can help me please?

I really thanks you.
Thomas 

Posted: Jul 28, 2004 - 03:57 AM   

Hi

Basically the problem here is that some sections cannot be placed in banked RAM.

This is the case for the stack. remember that the stack pointer register is 2 byte wide

So you will not be able to get the stack on banked RAM.

If you are working in banked memory model, DEFAULT_RAM must also be placed in non-banked RAM.

In banked memory model make sure to allocate only sections defined with the PPAGE attribute in banked RAM.

mw_cbezy

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