Motorola 68HC12BC32 - Manual (Page 15)

15
TROUBLESHOOTING TROUBLESHOOTING
The CME-12B/BC board is fully tested and operational before shipping. If it fails to function
properly, inspect the board for obvious physical damage first. Ensure that all IC devices in
sockets are properly seated. Verify the communications setup as described under GETTING
STARTED and see the Tips and Suggestions sections following for more information.
The most common problems are improperly configured communications parameters, and
attempting to use the wrong COM port.
1. Verify that your communications port is working by substituting a known good serial
device or by doing a loop back diagnostic.
2. Verify the jumpers on the board are installed correctly.
3. Verify the power source. You should measure approximately 9 volts between the GND
and +9V test point pads on the board.
4. If no voltage is found, verify the wall plug connections to 115VAC outlet and the power
connector.
5. Disconnect all external connections to the board except for COM1 to the PC and the wall
plug.
6. Make sure that the RESET line is not being held low.
Check for this by measuring the RESET pin on P4 for +5V.
7. Verify the presence of an 8MHz sine wave on the crystal, or 2MHz E clock signal if
possible.