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F1 EVALUATION PLATFORM
USER’S GUIDE
2010 Microchip Technology Inc. DS41401B-page 29
Chapter 6. Troubleshooting
6.1 INTRODUCTION
There may come a time when you need to determine why your F1 Evaluation Platform
is not performing correctly. This chapter lists a few of the problems that can prevent
proper operation.
6.2 COMMON PROBLEMS
6.2.1 The board will not power up
Make sure there is no shorting jumper at JP3. Then, go back and review Chapter
2. “Getting Started” of this manual.
6.2.2 LCD is blank, but everything else works
The demo code in supplied with the F1 Evaluation Platform uses the Timer1 oscillator
to drive the LCD. If the Timer1 oscillator is not oscillating, the LCD will remain blank.
Here are some steps to assure that the Timer1 oscillator is working properly.
1. Clean and dry the board especially around the components at the top right corner
of the PIC16LF1937.
2. Make sure no foreign material is shorting the crystal leads.
3. If you are using the RC0 and RC1 pins for some other function, you should
modify lcd_init to reconfigure the LCD peripheral for a different clock
source.
The Timer1 oscillator of the PIC16LF1937 is a very low-power design that can be easily
disrupted by stray leakage. In an actual application, Microchip recommends that the
crystal circuit be conformal coated to prevent leakage. Please review Application Note
AN1288, “Design Practices for Low-Power External Oscillators” for more information.
6.2.3 The motor spins, but then stops
The BLDC start-up algorithm could be having trouble finding the BEMF zero-crossing
signal required to synchronize the motor commutation.
If you have attached the BLDC add-on board and you are using the supplied BLDC
motor, then the pot labeled iRef needs to be turned completely counter clockwise to
assure that a good BEMF zero-crossing signal is detected by the PIC16LF1937.
If you are using a different motor, you need to adjust the zero-crossing threshold to
match the requirements of the motor. For more information, consult the documentation
supplied with the BLDC add-on board.