Diff: Glowing.cpp

Revision:

0:26c09c4aba81

Child:

1:eef7593bdcc5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Glowing.cpp	Wed Dec 29 03:32:39 2010 +0000
@@ -0,0 +1,44 @@
+#include "mbed.h"
+#include "math.h"
+#include "Glowing.h"
+
+Glowing::Glowing(PinName pin, float period, int steps, int offset) {
+    // Set the constants
+    s_port          = new PwmOut(pin);
+    s_steps         = steps;
+    s_step_offset   = offset;
+    c_circle        = 2*acos(-1.0);    // 2 PI
+    c_step_time     = period/steps;
+    c_step_gradient = c_circle/steps;
+    s_running       = false;
+}
+
+Glowing::~Glowing() {
+    Stop();
+}
+
+int Glowing::scale(float x) {
+    // Scaling the input value from [-1.0 - 1.0] to [0 - 1000]
+    return (int)((x + 1.0)*1000/2);
+}
+void Glowing::next(void) {
+    // Set the PWM value
+    s_port->pulsewidth_us(s_next_v);
+    // Calculate the next step and the corresponding PWM value
+    s_next_n  = (s_next_n + 1) % s_steps;
+    s_next_v  = scale(cos(s_next_n * c_step_gradient));
+}
+
+void Glowing::Start(void) {
+    s_port->period_ms(1);
+    s_next_v = 0.0;
+    s_next_n = s_steps/2 + s_step_offset;
+    attach(this, &Glowing::next, c_step_time);
+    s_running = true;
+}
+
+void Glowing::Stop(void) {
+    if (s_running) {
+        detach();
+    }
+}
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