DM163045 Microchip Technology, DM163045 Datasheet - Page 59

• Manufacturer Part Number: DM163045
• Description: PICDEM Lab Development Kit (with PICkit 3) General Purpose
• Manufacturer: Microchip Technology
• Series: PICDEM™r
• Type: MCUr

Specifications of DM163045

• Contents: Board, PIC kit 3
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC Micro® MCU

© 2009 Microchip Technology Inc.
The PB_PressISR() now checks to see if the voltage level on RA2 has changed
state from a 1-to-0 or from 0-to-1. Each condition will change the direction that the
LEDs flash sequentially. Note that the direction bit toggle used in previous labs has
been replaced by assigning either a ‘1’ for the left-to-right direction or ‘0’ for the
right-to-left direction. As discussed earlier, the PORTA register must be read before the
first interrupt can occur and at the end of each subsequent ISR execution to ensure that
the microcontroller has an up-to-date reference to measure the current state of the RA2
pin.
The Initialize() for this lab configures the peripherals and interrupts as follows:
• PORTC
• PORTA
• Timer0
• Global Variables
• Interrupt
3.4.6.3
Using the firmware developed in the previous lab, make the following changes:
1. Copy/paste the code in Example 3-26 into the PB_PressISR() over the code
- Clears PORTC
- Configures all pins as digital output
- Clears PORTA
- Configures RA2 as a digital input
- Uses the F
- Increment TMR0 on rising F
- Use Prescaler at 1:32
- Initialize direction to ‘0’
- Initialize LED_Output to ‘0’
- Enable RA2 Interrupt-on-Change
- Enable change interrupts in INTCON by setting the RABIE bit
- Clear the RABIF change interrupt flag in INTCON
- Enable Global Interrupts by setting GIE
- Read PORTA to latch current value on RA2 for reference
from the previous lab.
PROCEDURE
OSC
General Purpose Input/Output Labs
/4 as clock source
OSC
/4 clock edge
DS41369A-page 55