Keil Logo


It can be difficult to debug and diagnose FlashMon51 configuration failures. Fortunately, there are only a few things that cause FlashMon51 problems.

If FlashMon51 does not start correctly it is typically a problem with:

  • The Monitor Code Location
  • The Monitor Data Location
  • The Serial Interface Initialization.

If FlashMon51 stops working or behaves strangely while debugging, your application is most likely overwriting the monitor XDATA memory. To determine if this is the case, check the XDATA MEMORY MAPPING in the Linker MAP (*.M51) file and compare it with the monitor XDATA memory area listed under Peripherals — Target Settings — Monitor-51 Identification.

If FlashMon51 cannot single-step instructions or read or write SFR data then it is unable to modify the contents of the Flash memory. Double check the flash programming algorithms in the INSTALL.A51 configuration file.

During operation the Monitor might report the following errors:

    This error indicates that µVision has lost the serial connection to the Monitor program. It occurs if your program reinitializes the serial interface used by the monitor. This error may also occur if you single-step into the serial I/O routines of your application.
    This error occurs if you attempt to download code into the ROM space or into non-existing memory. Make certain that you have valid Flash programming functions for the memory region.
    This error occurs when the monitor cannot install the interrupt vectors for the serial interface or when the code memory at address 0 cannot be accessed. If you receive this error, it is likely that the IAP Flash programming routine does not work for this address region.
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.