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Accessing External Memory Devices

Hey all,

I am using uVision 3 and a Phytec 2294 board.

I have an external memory device connected to the phytec expansion board. The external device is using /CS0, although from talking to phytec, I am not sure if that is quite right.

I have set up the external memory space in the project options like so:
Start: 0x80000000 Size: 0x4

When I define a variable like :

#define volatile var x __at 0x8000000

and step through my code, any write/read to that variable doesnt seem to take place at the right addresses.

Can anyone give a clue as to what I may have missed?
Thanks

Doug

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  • Dan,

    Another thing I just noticed is that if I stored this in the target options

    start of 0x83000000, and size of 0x4,

    the compiler gives me this:

    *** ERROR L107: ADDRESS SPACE OVERFLOW
        SPACE:   DATA
        SEGMENT: STACK
        LENGTH:  00000490H
    *** WARNING L23: UNRESOLVED EXTERNAL SYMBOLS
    *** ERROR L128: REFERENCE MADE TO UNRESOLVED EXTERNAL
        SYMBOL:  ?C?INIT
        ADDRESS: 00000104H
    Program Size: data=1172 const=0 code=296
    Target not created
    


    But if I give it a much larger size, like 0x4000, it takes it just fine and operates properly, Any idea why it doesnt like the smaller size?

    Doug

Reply
  • Dan,

    Another thing I just noticed is that if I stored this in the target options

    start of 0x83000000, and size of 0x4,

    the compiler gives me this:

    *** ERROR L107: ADDRESS SPACE OVERFLOW
        SPACE:   DATA
        SEGMENT: STACK
        LENGTH:  00000490H
    *** WARNING L23: UNRESOLVED EXTERNAL SYMBOLS
    *** ERROR L128: REFERENCE MADE TO UNRESOLVED EXTERNAL
        SYMBOL:  ?C?INIT
        ADDRESS: 00000104H
    Program Size: data=1172 const=0 code=296
    Target not created
    


    But if I give it a much larger size, like 0x4000, it takes it just fine and operates properly, Any idea why it doesnt like the smaller size?

    Doug

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