Sam Walsh
This program counts the frequency of a single output encoder on pin D2 it can be changed to suit your encoder by changing the defines at the top and playing with the sample time.
Diff: main.cpp
- Revision:
- 0:fb3e19364d48
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Tue Jan 26 12:54:37 2016 +0000
@@ -0,0 +1,37 @@
+#include "mbed.h"
+
+#define TICKS_PER_REVOLUTION 12.0
+#define TICK_CHECK_PERIOD 0.1
+
+DigitalOut myled(LED1);
+Serial pc(USBTX, USBRX); // tx, rx
+Ticker periodicTimer1, periodicTimer2;
+
+float speed_rpm, speed_rps, ticks_per_second;
+volatile unsigned int tick_counter, final_count;
+
+InterruptIn freqInputPin(D2);
+
+void freqInputPin_Interrupt() {
+ //Triggers on the rising edge of the frequency signal
+ tick_counter++;
+}
+
+void check_TickCount(){
+ final_count = tick_counter;
+ //pc.printf("\n\rTick Count is : %d", final_count);
+ tick_counter = 0;
+}
+
+void display_TickCount(){
+ //pc.printf("\n\r Final Count is : %.2f", (float) final_count*(1.0/TICK_CHECK_PERIOD));
+ pc.printf("\n\r Speed in RPM is : %.2f", (float)(final_count*(1.0/TICK_CHECK_PERIOD))*(60.0/TICKS_PER_REVOLUTION));
+}
+
+int main() {
+ freqInputPin.rise(&freqInputPin_Interrupt); //chain interrupt to rising edge
+ periodicTimer1.attach(&check_TickCount, TICK_CHECK_PERIOD);
+ periodicTimer2.attach(&display_TickCount, 1.0); //Display conut once a second
+ while(1) {
+ }
+}