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#include "xc.h"
#include "lab4_button.h"
#define circBuffSize 2
void initPushButton(){
//Configure Timer 2 (500ns / count, 25ms max).
// note that resolution = 500ns = 8 x 62.5ns, max period = 25ms = Tcy * 8 * 50,000
T2CONbits.TON = 0;
T2CONbits.TCKPS = 0b11;
T2CONbits.TCS = 0b0;
T2CONbits.TGATE = 0b0;
TMR2 = 0;
PR2 = 62500; // Set period to be larger than max external sig duration
T2CONbits.TON = 1; // Start 16-bit Timer2
// Initialize the Input Capture Module
IC1CON = 0; // Turn off and reset internal state of IC1
IC1CONbits.ICTMR = 1; // Use Timer 2 for capture source
IC1CONbits.ICM = 0b011; // Turn on and capture every rising edge
IC1CON = 1;
_IC1IF = 0; // Clear IC1 Interrupt Status Flag
_IC1IE = 1; // Enable IC1 interrupt
_T2IF = 1;
_T2IE = 1;
}
volatile unsigned long overflow = 0;
//Timer 2 overflow interrupt
//Each overflow is one second
void __attribute__((__interrupt__,__auto_psv__)) _T2Interrupt(void) {
_T2IF = 0;
overflow++;
}
//Buffer functions
volatile unsigned long buffer[circBuffSize];
int buffSize = 0, write = 0, read = 0;
void addBuffer(unsigned long x) {
if (buffSize < circBuffSize) {
buffer[write++] = x;
write %= circBuffSize;
++buffSize;
}
//Otherwise get rid of the data.
}
unsigned long getBuffer() {
unsigned long returnValue = buffer[read++];
read %= circBuffSize;
--buffSize;
return returnValue;
}
int emptyBuffer(void) {
if (buffSize <= 0) {
buffSize=0;
return 1;
} else {
return 0;
}
}
volatile unsigned long curPeriod = 0, prevPress = 0, currPress = 0;
//IC1 interrupt
void __attribute__((__interrupt__,__auto_psv__)) _IC1Interrupt(void) {
_IC1IF = 0;
unsigned int time;
currPress = (IC1BUF + 62500 * (long) overflow);
curPeriod = currPress - prevPress;
time = curPeriod / 62.5;
if (time > 10) {
addBuffer(time);
}
prevPress = currPress;
}
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