User manual

© 2008 Microchip Technology Inc. DS51721B-page 23
PICDEM™ PIC18 EXPLORER
DEMONSTRATION BOARD
USER’S GUIDE
Chapter 3. PICDEM™ PIC18 Explorer Demonstration
Board Tutorial Program
The tutorial program is preprogrammed into the PIC18F8722 on the PICDEM PIC18
Explorer Demonstration Board. This program is also on the PICDEM PIC18 Explorer
Demonstration Board kit’s CD-ROM so that it can be reprogrammed on the sample
device if it the device had been preprogrammed.
For detailed information on the PICDEM PIC18 Explorer Demonstration Board
hardware, see Appendix A. “Hardware Details”.
3.1 TUTORIAL PROGRAM OPERATION
The tutorial program consists of three components that appear sequentially on the
board’s LCD. A flowchart, showing the button navigation through the entire program, is
given in Figure 3-2.
When the board boots up, the device name appears on the LCD and the program
proceeds to the first component.
To select menu options, use the RB0 and RA5 buttons on the bottom of the board (see
Figure 3-1).
FIGURE 3-1: RB0 AND RA5 BUTTONS
1. Voltmeter
This mode uses the Analog-to-Digital Converter (A/D) module to measure the voltage
of the R3 potentiometer and display a value between 0.00V and 5.00V on the LCD. (In
the case of 3.3V devices, the displayed value will be 0.00V to 3.3V.)
The voltage reading is updated continually until the mode is exited by pressing RB0.
2. Temperature
This mode uses an MCP9701A thermal sensor to measure ambient temperature in
Celsius and displays it on the LCD. The program also stores the current temperature,
when exited, by writing to a defined address on the external, on-board EEPROM.
Communication between the microcontroller and sensor is done by the A/D module.
To exit this mode, press RB0.
RB0 Button
RA5 Button