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how to use external program/data memory address up to 64k/1M?

Hi,

I got a chip from WINBOND, w78c438c. It claims that it support 64kb program/1MB data memory space for applications which need additional external memory to store large amount of data .

does that mean that my constant data (less than 1MB) can be access by functions in each bank? ( In my case, the constant data have about 300K, and 8 banks are used). I don't see that the chip will support FAR constant type.

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  • does that mean that my constant data (less than 1MB) can be access by functions in each bank?

    The versions of the '51 that have "extended linear addressing" (and I assume that is the case for your chip) do not employ banking but a 24 bit addressing scheme.

    Erik

  • Take a look to the folder:
    C:\Keil\c51\Examples\FarMemory

    It contains several examples that help you to understand the configuration. For example:

    - 1MB Constants on Classic 8051

    Basically you need to adopt just the L51_BANK.A51 file and enable ?B_VAR_BANKING. This allows you already to use the 'far' memory type with classic 8051 devices.

  • Take a look to the folder:
    C:\Keil\c51\Examples\FarMemory

    It contains several examples that help you to understand the configuration. For example:

    - 1MB Constants on Classic 8051

    Basically you need to adopt just the L51_BANK.A51 file and enable ?B_VAR_BANKING. This allows you already to use the 'far' memory type with classic 8051 devices.