Callum Ellor
Freq calculations using counters and interrupt
Dependencies: FastPWM PwmIn USBDevice mbed
Revision 0:6d4f91decc4f, committed 2014-11-13
- Comitter:
- Ellor1
- Date:
- Thu Nov 13 13:26:08 2014 +0000
- Commit message:
- Freq calculation of signal using counters and interrupt routines
Changed in this revision
diff -r 000000000000 -r 6d4f91decc4f FastPWM.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/FastPWM.lib Thu Nov 13 13:26:08 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/Sissors/code/FastPWM/#ba7a5bf634b3
diff -r 000000000000 -r 6d4f91decc4f PwmIn.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PwmIn.lib Thu Nov 13 13:26:08 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/simon/code/PwmIn/#6d68eb9b6bbb
diff -r 000000000000 -r 6d4f91decc4f USBDevice.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/USBDevice.lib Thu Nov 13 13:26:08 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/USBDevice/#4d3e7f3d5211
diff -r 000000000000 -r 6d4f91decc4f main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Nov 13 13:26:08 2014 +0000
@@ -0,0 +1,122 @@
+#include "FastPWM.h"
+#include "mbed.h"
+#include "PwmIn.h"
+#include "USBSerial.h"
+
+// using fastpwm signal as a clock signal to be used to trigger the counter whilst the signal I want to measure is high.
+// to get this to work properly I believe I will need to use nested interrupts along with setting interupt priorities. This is so that
+// 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
+// which will continuoulsy count until the (led) signal causes another interrupt by going low.
+
+// clkin is currently set as a DigitalIn but this likely needs to become an interrupt.
+
+USBSerial serial;
+
+FastPWM clkoutput(p20);
+DigitalIn clkin(p8);
+InterruptIn led(p7);
+Ticker display;
+
+int count;
+int count_2;
+int t_rise;
+int t_fall;
+int t_period = 0;
+
+
+void clock_pulse() {
+
+ clkoutput.period(8e-7); //around 1.2 MHz signal
+ clkoutput.write(0.5f); // 50% duty cycle
+ }
+
+
+void rise() { // rising edge interrupt routine
+
+ while (led && clkin) { // whilst the signal I want to measure is high (led) and the clk signal (clkin) is high increment the counter
+ // if (clkin) {
+ count++;
+ }
+ // if (led && clkoutput) {
+
+ // count++;
+ // while (led) {
+ // if (clkin) {
+ // count++;
+ // }
+ t_fall = count_2;
+ // count_2 = 0;
+ }
+ // }
+
+ void fall() { // falling edge interrupt routine
+
+ while (!led && clkin) { // whilst the signal I want to measure is low and the clk signal is high increment counter 2
+ count_2++;
+ }
+ t_rise = count;
+ // count = 0;
+
+ }
+
+// }
+
+/*void period() {
+ t_period = count;
+ count = 0;
+ }
+*/
+
+void disp() {
+
+ serial.printf("count is %d \n\r" , t_rise);
+ serial.printf("count_2 is %d \n\r" , t_fall);
+ }
+
+
+int main()
+{
+ clock_pulse();
+
+ led.rise(&rise); // set rising edge interrupt and call rise function
+ led.fall(&fall); // set falling edge interrupt and call fall function
+ //count = 0;
+ // }
+
+ display.attach(&disp, 2); // ticker function to display results every 2 seconds
+
+ while (1) {
+
+ // while (led) {
+ // if (clkin) {
+ // count++;
+ // }
+ // count = 0;
+ //}
+
+ // if (led == 1) && (clkoutput == 1) {
+
+ // count++;
+
+ /*
+
+ while (led) {
+
+ if (clkin) {
+
+ count++;
+ }
+
+ */
+
+
+ }
+
+ //serial.printf("Pulsewidth is %.2f \n\r" , pa.pulsewidth());
+
+
+
+
+
+}
+
diff -r 000000000000 -r 6d4f91decc4f mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Thu Nov 13 13:26:08 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/031413cf7a89 \ No newline at end of file