Diff: freq_task.cpp

Revision:

4:48761259552a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/freq_task.cpp	Tue Mar 14 14:46:43 2017 +0000
@@ -0,0 +1,47 @@
+/**
+ * Task for getting the frequency from digital input on pin13. 
+ * The frequency is calculated by counting the number of rises
+ * on the pin. This is done using an interupt handler.
+ *
+ * Author: Jacob Baungard Hansen
+ */
+#include "freq_task.h"
+
+FrequencyTask::FrequencyTask(int starting_offset, int frequency_ms,
+                                                                     State * state)
+                                    : Task(starting_offset, frequency_ms) {
+                                        
+    this->state = state;
+    this->count = 0;
+    this->interrupt = new InterruptIn(p13); 
+
+}
+
+FrequencyTask::~FrequencyTask() {
+    delete this->interrupt;
+}
+
+/**
+ * This is called by the interupt, simply adds one to the count
+ */
+void FrequencyTask::counter() {
+    this->count++;
+}
+
+void FrequencyTask::action() {
+    // reset the count
+    this->count=0;
+    // Enable the iterrupt
+    this->interrupt->rise<FrequencyTask>(this, &FrequencyTask::counter);
+    // wait for a specied amout of time
+    wait_ms(SAMPLE_LENGTH_MS);
+    // disable interrupts
+    this->interrupt->rise(NULL);
+    //interupt.rise<FrequencyTask>(this, NULL); This crashes, should report bug to ARM
+    int freq = 0;
+    if (this->count > 0) {
+        freq = count/(SAMPLE_LENGTH_MS*0.001);
+    }
+    
+    this->state->set_freq(freq);
+}
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