main.cpp

00001 #include "mbed.h"
00002 
00003 #define TICKS_PER_REVOLUTION    12.0
00004 #define TICK_CHECK_PERIOD       0.1
00005 
00006 DigitalOut myled(LED1);
00007 Serial pc(USBTX, USBRX); // tx, rx
00008 Ticker periodicTimer1, periodicTimer2;
00009  
00010 float speed_rpm, speed_rps, ticks_per_second;
00011 volatile unsigned int tick_counter, final_count;
00012 
00013 InterruptIn freqInputPin(D2); 
00014 
00015 void freqInputPin_Interrupt() {
00016     //Triggers on the rising edge of the frequency signal
00017     tick_counter++;
00018 }
00019 
00020 void check_TickCount(){
00021     final_count = tick_counter;
00022     //pc.printf("\n\rTick Count is : %d", final_count);
00023     tick_counter = 0;
00024 }
00025 
00026 void display_TickCount(){
00027    //pc.printf("\n\r Final Count is : %.2f", (float) final_count*(1.0/TICK_CHECK_PERIOD));
00028    pc.printf("\n\r Speed in RPM is  : %.2f", (float)(final_count*(1.0/TICK_CHECK_PERIOD))*(60.0/TICKS_PER_REVOLUTION));
00029 }
00030 
00031 int main() {
00032     freqInputPin.rise(&freqInputPin_Interrupt); //chain interrupt to rising edge
00033     periodicTimer1.attach(&check_TickCount, TICK_CHECK_PERIOD);
00034     periodicTimer2.attach(&display_TickCount, 1.0); //Display conut once a second
00035     while(1) { 
00036     }
00037 }