EmbeddedArtists AB
/
lpc812_exp_solution_stepper-motor
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Dependencies: lpc812_exp_lib_PCF8591 mbed
Diff: main.cpp
- Revision:
- 0:9a590fe3a1a1
diff -r 000000000000 -r 9a590fe3a1a1 main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Mon Nov 25 14:47:27 2013 +0000
@@ -0,0 +1,299 @@
+#include "mbed.h"
+#include "PCF8591.h"
+
+DigitalOut ph1(D10);
+DigitalOut ph2(D11);
+DigitalOut ph3(D12);
+DigitalOut ph4(D13);
+
+PCF8591 adc;
+
+Serial pc(USBTX, USBRX);
+
+static void experiment1()
+{
+ // Delay between steps
+ float number = 0.5;
+
+ // Initialize outputs
+ ph1=1;
+ ph2=1;
+ ph3=1;
+ ph4=1;
+ pc.printf("\nStarting program...\n");
+
+ while(1) {
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ wait(number);
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ wait(number);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ wait(number);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ wait(number);
+ }
+}
+
+static void experiment2_alt1()
+{
+ // Delay between steps
+ float number = 0.5;
+
+ // Initialize outputs
+ ph1=1;
+ ph2=1;
+ ph3=1;
+ ph4=1;
+ pc.printf("\nStarting program...\n");
+
+ while(1) {
+ //read trimming potentiometer and convert to value in the 0-0.5 range
+ number = adc.read(PCF8591::A0);
+ number = number/512; //
+ pc.printf("%f\n", number);
+
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ wait(number);
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ wait(number);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ wait(number);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ wait(number);
+ }
+}
+
+#define ALPHA 0.6
+float getDelayAndDirection()
+{
+ static float lastValue = 0;
+
+ // read a value
+ int v = adc.read(PCF8591::A0);
+
+ // convert from 0..255 to -0.5..0.5
+ float f = v - 128;
+ f = f/256;
+
+ // apply filter
+ lastValue = (ALPHA * lastValue) + (1-ALPHA) * f;
+
+ return f;
+}
+
+static void experiment2_alt2()
+{
+ // Delay between steps
+ float delay = 0.5;
+
+ // Direction
+ bool clockwise = true;
+
+ // Initialize outputs
+ ph1=1;
+ ph2=1;
+ ph3=1;
+ ph4=1;
+ pc.printf("\nStarting program...\n");
+
+ while(1) {
+ delay = getDelayAndDirection();
+ pc.printf("%f\n", delay);
+
+ // determine direction and make sure speed is lowest around 0
+ clockwise = (delay < 0);
+ delay = 0.5 - abs(delay);
+
+ if (clockwise) {
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ wait(delay);
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ wait(delay);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ wait(delay);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ wait(delay);
+ } else {
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ wait(delay);
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ wait(delay);
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ wait(delay);
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ wait(delay);
+ }
+ }
+}
+
+int getTargetStep(bool filter)
+{
+ static int lastValue = -1;
+
+ // read a value
+ int v = adc.read(PCF8591::A0);
+
+ if (lastValue == -1) {
+ lastValue = v;
+ }
+
+ // apply filter
+ if (filter) {
+ lastValue = ((3*lastValue) + v) >> 2;
+ } else {
+ lastValue = v;
+ }
+
+ // convert from 0..255 to 0..19
+ return lastValue/13;
+}
+
+static void experiment3()
+{
+ // Delay between steps
+ float delay = 0.05;
+
+ // Current step
+ int current = 0;
+
+ // Initialize outputs
+ ph1=1;
+ ph2=1;
+ ph3=1;
+ ph4=1;
+ pc.printf("\nStarting program...\n");
+
+
+ while(1) {
+ int target = getTargetStep(true);
+
+ if (target == current) {
+ wait(0.02);
+ continue;
+ }
+ //pc.printf("%d -> %d\n", current, target);
+
+ int clockwise = (target + 20 - current) % 20;
+ int anticlockwise = (current + 20 - target) % 20;
+ if (clockwise < anticlockwise) {
+ for (int i = 0; i < clockwise; i++) {
+ switch (current%4) {
+ case 0:
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ break;
+ case 1:
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ break;
+ case 2:
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ break;
+ case 3:
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ break;
+ }
+ wait(delay);
+ current++;
+ }
+ } else {
+ for (int i = 0; i < anticlockwise; i++) {
+ switch (current%4) {
+ case 0:
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 1;
+ ph4 = 0;
+ break;
+ case 1:
+ ph1 = 0;
+ ph2 = 1;
+ ph3 = 0;
+ ph4 = 1;
+ break;
+ case 2:
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 0;
+ ph4 = 1;
+ break;
+ case 3:
+ ph1 = 1;
+ ph2 = 0;
+ ph3 = 1;
+ ph4 = 0;
+ break;
+ }
+ wait(delay);
+ current+=19;
+ }
+ }
+ current = current % 20;
+ }
+}
+
+int main()
+{
+ //experiment1(); // Fixed delay
+ //experiment2_alt1(); // Trimming pot controls delay
+ experiment2_alt2(); // Trimming pot controls delay and direction
+ //experiment3(); // Absolute positioning
+}
\ No newline at end of file