Motorola DG128 User Manual

TROUBLESHOOTING

The CMD912X 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 MODE, CONFIG, and COM switch settings are correct.

3. Verify the power source. You should measure approximately 9 volts between the GND

and +VIN connections on the TB1 power connector with the standard power supply
provided.

4. If no voltage is found, verify the wall plug connections to 115VAC outlet and the power

connector.

5. Verify the logic power source. You should measure +5 volts between the GND and +5V

connections on the TB1 power connector. If the +VIN supply is good and this supply is
not +5V, immediately disconnect power from the board. Contact support@axman.com by
email for instructions and provide board name and problem.

6. Disconnect all external connections to the board except for COM1 to the PC and the wall

plug.

7. Make sure that the RESET line is not being held low.

Check for this by measuring the RESET pin on P4 for +5V.

8. Verify the presence of a 16MHz square wave at the EXTAL pin or 8MHz E clock signal if

possible.

9. Contact support@axman.com by email for further assistance. Provide board name and

describe problem.