DSCOPE: SERIAL INTERFACE PROBLEMS WITH THE MONITOR

QUESTION

I'm using dScope with the MONitor installed in my target board and I'm getting communication problems between dScope and the target board. What can I do to fix this problem?

ANSWER

There are a number of things that can prevent dScope from properly communicating with your target board. In nearly every case, the problem lies with the serial port configuration on your PC. The following suggestions may help you get up and running. Unfortunately, the PC's serial port does require some configuration and testing to get it working reliably.

1. Make sure that you have selected the correct COM port on your PC or Laptop.
2. Make sure that the serial cable you use is wired correctly.
3. Make sure that power management is not disabling the serial port on your PC or Laptop.
4. Under Windows 95 and Windows NT, check the serial port settings. There are a number of things to try here. Try these options one at a time to see what works.
   • Make sure you set the baud rate to something above the actual baud rate you use. 38.4K or 57.6K should do the trick.
   • Set handshaking to none.
   • Go into advanced options and disable the FIFO. Make sure that you don't have a COM port and an internal modem sharing the same IRQ and/or I/O address. This type of conflict will definitely cause problems.
5. We have found that step #4 (configuring the serial port) seems to solve most problems. If you use the 166 tools and have troubles with the boot loader only getting partially downloaded, check the FIFO settings. You may find that the FIFO is incorrectly enabled and that disabling the FIFO cures the problem.

SEE ALSO

• C51: CALCULATING BAUD RATES FOR THE 8051 SERIAL PORT
• MON51: CONFIGURING FOR TARGET
• MON51: CONNECTION TO TARGET SYSTEM LOST

Last Reviewed: Saturday, July 09, 2005