Datasheet
Demonstration Program Operation
© 2006 Microchip Technology Inc. DS51584B-page 31
If any of these tests fail, then at the end of the Tone test the LED corresponding to the
failed test will blink slowly (2 blinks/sec). For example, if RD4 blinks, it means that the
UART test failed. The table below correlates the blinking LED with each test and
indicates the possible cause for the failure:
If all tests passed, then none of the LEDs will blink.
Blinking LED Test Failed Reasons for Failure
RD4 UART UART driver chip failed; UART shorting
jumper not connected on J1
RD5 Keypad S1 and S2 not working properly
RD6 Potentiometer Potentiometer R13 faulty
RD7 Digital Potentiometer/Op Amp Digital Potentiometer/Op Amp failed