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FAQ, Frequently Asked Questions

These tips should help you get going as you start programming your C language instrument control application using the PDQ Single Board Computer (SBC).


Why cant I can't communicate with my board?

Loss of communication with the Freescale 9S12 (HCS12) processor on the PDQ Board can happen for a number of different reasons.

  • Do you have the correct baud rate selected? The default is 115200, and can be changed by clicking the Settings→ Comm menu option in Mosaic Terminal.
  • Is the serial cable connected to Serial 1 on the pdq board? There are two serial ports, and by default Serial 1 is configured for user Forth commands and loading software.
  • Do you have the right COM port selected? To view available COM ports go to your Windows desktop. Right click on the "My Computer" icon and choose Properties. Click the Hardware tab and click Device Manager. Expand the list item: Ports (COM & LPT) and look at all available COM ports. You should choose one of these ports in Mosaic Terminal by clicking the Settings→ Comm menu option, and selecting the correct COM port from the drop-down menu.
    • If you are using a usb-to-rs-232-adapter and don't see a USB Serial Port listed in the Device Manager, you need to unplug the adapter, install the driver from the small CD included in the package with the adapter, and then re-connect the adapter.
    • If your computer has a built-in serial port but that port does not appear in the Device Manager, you may need to enable the serial port in your computer's BIOS. Watch the startup screen as your computer boots up to see which key to press to "Enter setup mode", and look through the BIOS menus for the serial port enable option.
  • Is your serial port/cable bad? Try another cable, try connecting to a different serial port, or if using a usb-to-rs-232-adapter, try connecting the adapter directly to the PowerDock or Mosaic DB-9 ribbon cable.
    • To verify the functionality of a port and cable independently from the PDQ Board or other device it is intended to communicate with, connect pins 2 and 3 of the serial cable as shown here. With pins 2 and 3 connected, type some characters into the terminal. If you can see each character as you type it, the serial port and cable are working. If you do not see the characters, there is a problem with the port or the cable. You can also connect these pins with a jumper shunt.

serial interface


How do I make my application start at power on?

To automatically start your application, see the autostarting-your-application section.


See also → Checklist
PDQ Board Users Guide

This page is about: Setting Correct Baud Rate, how Diagnose Serial Communications Problems – Here are some answers to frequently asked questions. These tips should help you get going as you start programming your C language instrument control application using the PDQ Board.