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mon51

aijun xu

I'm using PHILIPS 89C51RD2, it has 64K internal FLASH and ISP, how to modify MON51 program to fit this internal FLASH so that I can conect PHILIPS89C51RD2 chip with UV2 directly without external RAM expadation?

  • 0

    I'm using PHILIPS 89C51RD2, it has 64K internal FLASH and ISP, how to modify MON51 program to fit this internal FLASH so that I can conect PHILIPS89C51RD2 chip with UV2 directly without external RAM expadation?

    This will be difficult.

    RAM (rather than FLASH) is used because of the way the monitor sets breakpoints when you run and single-step thru your program.

    To set breakpoints (or single-step breakpoints), the monitor must replace instructions in your program with a jmp instruction (to branch to the monitor's breakpoint handler). This happens EVERY TIME you single-step.

    If you have only FLASH memory, then everytime you single-step, the monitor would have to read an entire FLASH page (however big that is), save it, erase the page, and re-program the page with the modified instruction.

    Not only is this complex, but it is incredibly slow, and will (eventually) exhaust the write cycles of the FLASH memory (OK, maybe not before we all die).

    If you still want to do this, take a look at the INSTALL.A51 file in the MON51 directory. There are routines in this file that read and write downloaded code. You can make your FLASH changes there.

    Jon

  • 0 in reply to Keil Support

    I'm using PHILIPS 89C51RD2, it has 64K internal FLASH and ISP, how to modify MON51 program to fit this internal FLASH so that I can conect PHILIPS89C51RD2 chip with UV2 directly without external RAM expadation?<br>
    <br>
    This will be difficult.<br>
    <br>
    RAM (rather than FLASH) is used because of the way the monitor sets breakpoints when you run and single-step thru your program.<br>
    <br>
    To set breakpoints (or single-step breakpoints), the monitor must replace instructions in your program with a jmp instruction (to branch to the monitor's breakpoint handler). This happens EVERY TIME you single-step.<br>
    <br>
    If you have only FLASH memory, then everytime you single-step, the monitor would have to read an entire FLASH page (however big that is), save it, erase the page, and re-program the page with the modified instruction.<br>
    <br>
    Not only is this complex, but it is incredibly slow, and will (eventually) exhaust the write cycles of the FLASH memory (OK, maybe not before we all die).<br>
    <br>
    If you still want to do this, take a look at the INSTALL.A51 file in the MON51 directory. There are routines in this file that read and write downloaded code. You can make your FLASH changes there.<br>
    <br>
    Jon<br>
    <br>