main.cpp

00001 #include "FastPWM.h"
00002 #include "mbed.h"
00003 #include "PwmIn.h"
00004 #include "USBSerial.h"
00005 
00006 // using fastpwm signal as a clock signal to be used to trigger the counter whilst the signal I want to measure is high. 
00007 // to get this to work properly I believe I will need to use nested interrupts along with setting interupt priorities. This is so that
00008 // when the signal I want to read  (led) causes an interrupt on a rising edge whilst this value is high I want the clock trigger to interrupt a seperate pin 
00009 // which will continuoulsy count until the (led) signal causes another interrupt by going low.
00010 
00011 // clkin is currently set as a DigitalIn but this likely needs to become an interrupt.
00012 
00013 USBSerial serial;
00014 
00015 FastPWM clkoutput(p20);
00016 DigitalIn clkin(p8);
00017 InterruptIn led(p7);
00018 Ticker display;
00019 
00020 int count;
00021 int count_2;
00022 int t_rise;
00023 int t_fall;
00024 int t_period = 0;
00025 
00026 
00027 void clock_pulse() {
00028     
00029       clkoutput.period(8e-7); //around 1.2 MHz signal
00030     clkoutput.write(0.5f);   // 50% duty cycle
00031     }
00032     
00033     
00034 void rise() { // rising edge interrupt routine 
00035   
00036    while (led && clkin) {           // whilst the signal I want to measure is high (led) and the clk signal (clkin) is high increment the counter
00037            //  if (clkin) {
00038                  count++;
00039                  }
00040   //  if (led && clkoutput) {
00041             
00042         //    count++;
00043    //     while (led) {
00044      //        if (clkin) {
00045      //            count++;
00046       //           }
00047              t_fall = count_2;   
00048             // count_2 = 0;
00049              }
00050   //  }
00051     
00052   void fall() { // falling edge interrupt routine
00053       
00054       while (!led && clkin) {  // whilst the signal I want to measure is low and the clk signal is high increment counter 2
00055           count_2++;
00056           }
00057           t_rise = count;
00058          // count = 0;
00059        
00060       }
00061   
00062 // }
00063 
00064 /*void period() {
00065     t_period = count;
00066     count = 0;
00067     }  
00068 */
00069 
00070 void disp() {
00071     
00072     serial.printf("count is %d \n\r" , t_rise);
00073     serial.printf("count_2 is %d \n\r" , t_fall);   
00074     }
00075 
00076 
00077 int main()
00078 {
00079     clock_pulse();
00080     
00081     led.rise(&rise); // set rising edge interrupt and call rise function
00082     led.fall(&fall); // set falling edge interrupt and call fall function       
00083              //count = 0;
00084            //  }
00085    
00086     display.attach(&disp, 2); // ticker function to display results every 2 seconds
00087 
00088    while (1) {
00089          
00090       //   while (led) {
00091           //   if (clkin) {
00092           //       count++;
00093             //     }
00094             // count = 0;
00095              //}
00096          
00097         // if (led == 1) && (clkoutput == 1) {
00098             
00099           //  count++;
00100          
00101            /*
00102   
00103   while (led) {
00104       
00105       if (clkin) {
00106           
00107           count++;
00108                    }        
00109           
00110   */
00111          
00112          
00113             }
00114 
00115         //serial.printf("Pulsewidth is %.2f \n\r" , pa.pulsewidth());
00116                 
00117 
00118 
00119 
00120 
00121 }
00122