Initial commit

src/main.cpp

@@ -0,0 +1,85 @@
+#include <Arduino.h>
+
+/*
+ * Function: configureTimer
+ * ----------------------------
+ *   Configures both 16bit timer for 25 kHz pwm signals.
+ */
+void configureTimer()
+{
+    // Configure Timer 1 for PWM @ 25 kHz.
+    TCCR1A = 0;   // undo the configuration done by...
+    TCCR1B = 0;   // ...the Arduino core library...
+    TCCR1C = 0;   // ...for pin 9, 10 and 11.
+    TCNT1  = 0;   // reset timer
+    // non-inverted PWM on ch. A, B and C, mode 10: ph. correct PWM, TOP = ICR1
+    // TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(COM1C1) | _BV(WGM11);
+    TCCR1B = _BV(WGM13) | _BV(CS10); // prescaler = 1
+    TCCR1C = _BV(WGM13) | _BV(CS10); // on PIN 9,10,11
+    ICR1   = 320;       // TOP = 320, @16Mhz CPU -> 25kHz PWM
+    OCR1A = 5;          // Set duty-cycle
+    // Configure Timer 3
+    // TCCR3A = 0;
+    // TCNT3  = 0;
+    // TCCR3A = _BV(COM1A1) | _BV(WGM11);
+    // TCCR3B = _BV(WGM13) | _BV(CS10);
+    // ICR3   = 320;
+
+    // pretty slow ~1000hz
+    // TCCR1A = 0;            //clear timer registers
+    // TCCR1B = 0;
+    // TCNT1 = 0;
+
+    // TCCR1B |= _BV(CS12) | _BV(CS11) | _BV(CS10);   //no prescaler
+    // ICR1 = 320;            //PWM mode counts up 320 then down 320 counts (25kHz)
+
+    // TCCR1A |= _BV(COM1A1); //output A clear rising/set falling
+
+    // TCCR1A |= _BV(COM1B1); //output B clear rising/set falling
+
+    // TCCR1B |= _BV(WGM13);  //PWM mode with ICR1 Mode 10
+    // TCCR1A |= _BV(WGM11);  //WGM13:WGM10 set 1010
+}
+
+
+/*
+ * Function: setup
+ * ----------------------------
+ *   Default arduino setup function, calls all the initialization functions.
+ */
+void setup()
+{
+    Serial.begin(9600);     // initialization of serial over usb.
+    delay(500);            // wait a bit for external program to connect.
+ 
+    
+    Serial.println("set output pins...");
+    pinMode(2, OUTPUT);
+    pinMode(9, OUTPUT);
+    pinMode(7, INPUT);
+
+    // configure timer
+    Serial.println("configure timer for 25kHz PWM...");
+    configureTimer();
+
+    Serial.println("fan control setup done.");
+}
+
+void loop()
+{
+    int last = digitalRead(7);
+
+    while (1) {
+        int next = digitalRead(7);
+
+        if (!last && next) {
+            digitalWrite(2, HIGH);
+        } else {
+            digitalWrite(2, LOW);
+        }
+
+        last = next;
+
+        delayMicroseconds(200);
+    }  
+}