User manual

PICDEM™ LCD 2 Demonstration Kit User’s Guide
DS51662C-page 48  2010 Microchip Technology Inc.
A.11 TEMPERATURE SENSOR
A 10 kTC thermistor (R11) is provided to sense the temperature. It is connected to
AN1 (RA1) through the jumper, JP5. An optional unpopulated TC77-based circuit is
provided to read the temperature serially using the USART module. The jumpers, JP15
and JP16, are to be connected and RA1 of U1A should be made digital to be used to
enable TC77.
A.12 SWITCHES
Four switches provide the following functions for digital I/Os:
• S1 – Active-low switch connected to RB6.
• S2 – Active-low switch connected to RB6 and RB7.
• S3 – Active-low switch connected to RB6, RB7 and RA6.
• S4 – Active-low switch connected to RB6, RB7, RA6 and RA7.
For this type of sensing, the jumpers, JP1, JP2, JP6, JP18, JP19, JP9 and JP10,
should be connected and the potentiometer should be connected to AN0 through J11.
Sensing should be done in the sequence, S1, S2, S3 and S4, only. Individual switch
sensing is not allowed.
Additionally, the four switches provide the following functions for analog input (AN0):
• S1 – AN0 will be approximately at V
CC/2.
• S2 – AN0 will be approximately at V
CC/3.
• S3 – AN0 will be approximately at V
CC/5.2.
• S4 – AN0 will be approximately at V
CC/7.7.
For this type of sensing, the jumpers, JP1, JP2, JP6, JP18 and JP19, should not be
connected and the SWT should be connected to AN0 through J11.
A.13 ICD CONNECTOR
By way of the modular connector (J37), the MPLAB ICD 2 can be connected for
low-cost debugging. The ICD connector utilizes RB6/PGC and RB7/PGD of the
microcontrollers for in-circuit debugging.
Note 1: For the PIC18F85J90 and PIC18F87J90 PIM, the RA2 pin is connected
to RA1 of U1A and AN2 is used instead of AN1.
2: For the PIC18F8490, PIC16F/LF/1946/7, PIC16F946, and PIC16F917
PIMs, the RA1 pin is connected to RA1 of U1A.