diff options
Diffstat (limited to '')
| -rw-r--r-- | Lab4.X/lab4_button.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/Lab4.X/lab4_button.c b/Lab4.X/lab4_button.c new file mode 100644 index 0000000..611cf03 --- /dev/null +++ b/Lab4.X/lab4_button.c @@ -0,0 +1,47 @@ +#include "xc.h"
+#include "lab4_button.h"
+
+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 = 0xf424; // Set period to be larger than max external sig duration
+ T2CONbits.TON = 1; // Start 16-bit Timer2
+
+ // Initialize the Input Capture Module
+ IC1CONbits.ICTMR = 1; // Select Timer2 as the IC1 Time base
+ IC1CONbits.ICI = 0b00; // Interrupt on every capture event
+ IC1CONbits.ICM = 0b011; // Generate capture event on every Rising edge
+ // Enable Capture Interrupt And Timer2
+
+ IPC0bits.IC1IP = 1; // Setup IC1 interrupt priority level
+ IFS0bits.IC1IF = 0; // Clear IC1 Interrupt Status Flag
+ IEC0bits.IC1IE = 1; // Enable IC1 interrupt
+
+ IFS0bits.T2IF = 1;
+ IEC0bits.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++;
+}
+
+volatile long int curPeriod=0;
+//IC1 interrupt
+void __attribute__((__interrupt__,__auto_psv__)) _IC1Interrupt(void) {
+ static unsigned int prevEdge=0;
+ int curEdge;
+
+ _IC1IF = 0;
+ curEdge = IC1BUF + 62500L * overflow;
+ curPeriod = curEdge - prevEdge;
+ prevEdge = curEdge;
+}
|