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Setting Target Options

Options for Target ButtonUse the Options for Target toolbar button to display the Target dialog, and configure the Monitor-251 interface using the following steps:

  1. Enter the memory ROM area and RAM area for your target system.

    When you are using Monitor-251, the complete target application needs to be stored in RAM space. Therefore, you need to split the available RAM space on the MCBx51 into a ROM section for MCBx51 program code and a RAM section for data.

    Options for Target, RAM and ROM Settings In External Memory section #1, select ROM, then enter the starting address of 0xFF0000 in Start and the size of 0x8000 in Size.

    In External Memory section #2, select RAM, then enter the starting address of 0x0000 in Start and the size of 0x4000 in Size.

  2. In the Options for Target — L251 Locate dialog, you must reserve the memory used by Monitor-251.

    Enter in Reserve: 0xFF0003-0xFF0005, 0xFF003B-0xFF003D,0xFF007B-0xFF007D.

    Options for Target, L251 Locate

    Other required address ranges for the pre-configured Monitor may be found in Options for Target — Debug — Settings — Description.

  3. In the Options for Target — Debug dialog:

    Options for Target, Select 251 DriverClick the Use: radio button to select emulator mode, then select Keil Monitor-251 Driver from the drop-down list.

    Options for Target, Debug Startup OptionsEnable Load Application at Startup and Run to main() to automatically load and start your application when you start the debugger.

    Options for Target, Settings ButtonClick on the Settings button to open the Monitor-251 Driver Settings dialog.

  4. Options for Target, Monitor-251 Driver SettingsOn the Monitor-251Driver Settings dialog, select the COM Port you intend to use. The recommended Baudrate is 57600.


    • If you are using the MCBx51 INT RS232 port (on-chip 251 UART), the baudrate depends on the XTAL CPU clock. Select 19200 for the 12MHz XTAL, and 38400 for the 24MHz XTAL.
  5. Connect the serial interface to the PC and power up the MCBx51 board.
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