EmbeddedArtists AB
Solutions for the PWM experiments for LPC812 MAX
Dependencies: lpc812_exp_lib_PCF8591 mbed
Revision 0:6f393e96a8d1, committed 2013-11-22
- Comitter:
- embeddedartists
- Date:
- Fri Nov 22 12:40:14 2013 +0000
- Child:
- 1:08c2337bfa7b
- Commit message:
- First version
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/lpc812_exp_lib_PCF8591.lib Fri Nov 22 12:40:14 2013 +0000 @@ -0,0 +1,1 @@ +https://mbed.org/users/embeddedartists/code/lpc812_exp_lib_PCF8591/#53bf66c0e0f6
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Nov 22 12:40:14 2013 +0000
@@ -0,0 +1,151 @@
+#include "mbed.h"
+#include "PCF8591.h"
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+DigitalOut redLED(D0);
+DigitalOut greenLED(D1);
+
+PCF8591 adc;
+
+static void experiment1()
+{
+ // set wanted duty cycle
+ int wantedDutyCycle = 10;
+
+ // initialize LEDs to off
+ greenLED = redLED = 1;
+
+ pc.printf("Fixed duty cycle\n");
+ while(1) {
+ // set output high
+ greenLED = 1;
+
+ for (int loopCounter = 0; loopCounter < 100; loopCounter++) {
+ if (loopCounter == wantedDutyCycle) {
+ // set output low
+ greenLED = 0;
+ }
+ }
+ }
+}
+
+static int getDutyCycle(PCF8591::AnalogIn port)
+{
+ return (adc.read(port) * 100)/256;
+}
+
+static void experiment2()
+{
+ // set wanted duty cycle
+ int wantedDutyCycle = 10;
+
+ // initialize LEDs to off
+ greenLED = redLED = 1;
+
+ pc.printf("Trimpot controlled duty cycle\n");
+ while(1) {
+ wantedDutyCycle = getDutyCycle(PCF8591::A0);
+
+ // The duty cycle does not have to be read for each PWM loop
+ for (int num = 0; num < 200; num++) {
+ // set output high
+ greenLED = 1;
+
+ for (int loopCounter = 0; loopCounter < 100; loopCounter++) {
+ if (loopCounter == wantedDutyCycle) {
+ // set output low
+ greenLED = 0;
+ }
+ }
+ }
+ }
+}
+
+static void experiment3()
+{
+ // set wanted duty cycle
+ int wantedDutyCycle = 10;
+
+ // set wanted frequency
+ int delay = 1;
+
+ // initialize LEDs to off
+ greenLED = redLED = 1;
+
+ bool readDuty = true;
+
+ pc.printf("Trimpot controlled duty cycle and frequency\n");
+ while(1) {
+ // Don't want to read too often as that will return incorrect values
+ if (readDuty) {
+ wantedDutyCycle = getDutyCycle(PCF8591::A0);
+ } else {
+ delay = getDutyCycle(PCF8591::A1);
+ }
+ readDuty = !readDuty;
+
+ // Try to run PWM loop for about 50ms to allow ADC to produce correct values
+ for (int num = 0; num <= (500/(delay+1)); num++) {
+ // set output high
+ greenLED = 1;
+
+ for (int loopCounter = 0; loopCounter < 100; loopCounter++) {
+ if (loopCounter == wantedDutyCycle) {
+ // set output low
+ greenLED = 0;
+ }
+ wait_us(delay);
+ }
+ }
+ }
+}
+
+static void experiment4()
+{
+ // set wanted duty cycle
+ int wantedRedDutyCycle = 10;
+ int wantedGreenDutyCycle = 10;
+
+ bool readRed = true;
+
+ // initialize LEDs to off
+ greenLED = redLED = 1;
+
+ pc.printf("Trimpot controlled duty cycle (one per LED)\n");
+ while(1) {
+ if (readRed) {
+ wantedRedDutyCycle = getDutyCycle(PCF8591::A0);
+ } else {
+ wantedGreenDutyCycle = getDutyCycle(PCF8591::A1);
+ }
+ readRed = !readRed;
+
+
+ // The duty cycle does not have to be read for each PWM loop
+ for (int num = 0; num < 200; num++) {
+ // set outputs high
+ greenLED = 1;
+ redLED = 1;
+
+ for (int loopCounter = 0; loopCounter < 100; loopCounter++) {
+ if (loopCounter == wantedGreenDutyCycle) {
+ // set output low
+ greenLED = 0;
+ }
+ if (loopCounter == wantedRedDutyCycle) {
+ // set output low
+ redLED = 0;
+ }
+ }
+ }
+ }
+}
+
+int main()
+{
+ //experiment1(); // Fixed duty cycle
+ //experiment2(); // Trimpot controlled duty cycle
+ //experiment3(); // Trimpots controls duty cycle and frequency
+ experiment4(); // Trimpots controls one LED each
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Fri Nov 22 12:40:14 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/a9913a65894f \ No newline at end of file