Microchip Technology DV164136 User Manual
PICDEM™ PIC18 Explorer Demonstration Board User’s Guide
DS51721B-page 28
© 2008 Microchip Technology Inc.
A.1.5
Switches
The following switches are available:
• S1 – Active-low switch connected to RB0
• S2 – Active-low switch connected to RA5
• S3 – MCLR to hard reset the processor
• S4 – MCLR select switch.
If the on board, PIC18F8722 microcontroller is being used, set this to PIC MCU.
If an alternate, PIM-mounted microcontroller is being used, set this to ICE.
A.1.6
Oscillator Options
The main oscillator uses a 10 MHz crystal (Y1) which serves as the controller’s primary
oscillator. A second circuit, using a 32.768-kHz (watch type) crystal (Y2), functions as
the Timer1 oscillator, the source for the Real-Time Clock/Calendar (RTCC) and
secondary oscillator.
oscillator. A second circuit, using a 32.768-kHz (watch type) crystal (Y2), functions as
the Timer1 oscillator, the source for the Real-Time Clock/Calendar (RTCC) and
secondary oscillator.
The PIC18LF2450, the heart of the RS-232 to USB conversion, is independently
clocked with its own 12 MHz crystal (Y3).
clocked with its own 12 MHz crystal (Y3).
A.1.7
Analog Input (Potentiometer)
A 10 k
Ω potentiometer is connected through a series resistor to AN0. To provide an
analog input to one of the controller’s Analog-to-Digital (A/D) channels, the
potentiometer can be adjusted from V
potentiometer can be adjusted from V
DD
to GND.
A.1.8
ICD Connector
Microchip’s low-cost, in-circuit debugger, MPLAB ICD 2, can be connected to the
modular connector (J10). The ICD connector utilizes RB6 and RB7 for in-circuit
debugging.
modular connector (J10). The ICD connector utilizes RB6 and RB7 for in-circuit
debugging.
A.1.9
PICkit™ 2 Connector
Microchip’s low-cost programmer, PICkit 2, can be connected to the 6-pin interface
provided by J12.
provided by J12.
A.1.10
Temperature Sensor
The analog thermal sensor, MCP9701A (U1), is used for monitoring temperature. The
device is connected to the Analog-to-Digital Converter (A/D) module through RA1.
device is connected to the Analog-to-Digital Converter (A/D) module through RA1.
A.1.11
Serial EEPROM
A 25LC256, 256 Kbit (32K x 8) serial EEPROM (U9) is included for nonvolatile storage
of firmware.
of firmware.
The EEPROM also can demonstrate the operation of the Serial Peripheral Interface
(SPI) bus. The EEPROM is enabled or disabled from the SPI bus by jumper JP2.
(SPI) bus. The EEPROM is enabled or disabled from the SPI bus by jumper JP2.
A.1.12
PICtail™ Daughter Board Connector
The PICtail™ interface enables the PICDEM PIC18 Explorer Demonstration Board to
be connected directly to available PICtail daughter board cards. This provides a
one-to-one connection between the microcontrollers and the cards through SPI/I
be connected directly to available PICtail daughter board cards. This provides a
one-to-one connection between the microcontrollers and the cards through SPI/I
2
C™
interfaces.
Note:
For details, see Section 2.4.1 “Programming Requirements”.
Note:
For details, see Section 2.4.1 “Programming Requirements”.