From 92a95452f413f28bfc8aa9413772e76f4591fb99 Mon Sep 17 00:00:00 2001
From: RossTheRoss <msattr@gmail.com>
Date: Tue, 24 Mar 2020 12:13:19 -0500
Subject: e

---
 Lab4.X/lab4_button.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Lab4.X/lab4_button.c

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;
+}
-- 
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