Debug Options

To debug programs on your target system, you must configure the µVision Debugger to interface to MON251. Under Options for Target - Debug make sure to select Use: Keil Monitor-251 Driver.

Click on the Settings button to configure various parameters such as the COM port and baud rate.

• Comm Port Settings selects the PC COM port and the baudrate to use to connect to your target hardware.

  Note

  If you have problems connecting to your target hardware, try using 9600 baud. Sometimes non-standard baudrates allow different crystal frequencies on a target board without having to reinstall MON51. For example, a target board running at 12 MHz and 9600 baud can be modified to a 16MHz and 12800 baud by just exchanging the crystal.

• Cache Options speeds up the screen update. To view the actual value changes in memory mapped external peripherals, switch off the Cache Memory. For maximum performance, enable Cache Memory.
• Enable Serial Break allows you to use the serial interrupt of the UART to stop program execution. When Enable Serial Break is enabled, you can terminate a running application program with the Stop toolbar button or the ESC key in the uVision Debugger Command window.

  Note

  If you use this option, the serial interface is no longer available to the user program, and your application must not reset the global Interrupt Enable (SFR Bit EA in IE.7).

• Warm Start User Program: when this is checked, a CPU reset (after Power-Up) starts the user program at address 0x004000, otherwise the Monitor program is started. This feature must be used for USB devices to allow correct enumberation of the USB device (since the device gets an reset from the USB interface).