1 files changed, 87 insertions, 0 deletions
diff --git a/pcr-controller/pwm.c b/pcr-controller/pwm.c
new file mode 100644
index 0000000..3ca5bbe
--- /dev/null
+++ b/pcr-controller/pwm.c
@@ -0,0 +1,87 @@
+
+#include "pwm.h"
+
+//OutputCompareRegister for Timer1 and pin OC1A/B5
+#define PWMB5_VAL OCR1AL
+//for FastPWM in Timer4 OCR4C is TOP for all OC4x pins, all other PWM Modes use OCR4A,OCR4B or OCR4D
+#define PWMD7_VAL OCR4D
+
+void pwm_init(void)
+{
+  //for OC1A on pin B5
+  DDRB |= (1<<PB5);
+  TCCR1A = 0;
+  TCNT1 = 0;
+  OCR1A = 0;
+  TCCR1A = (1<<WGM10);  //Fast PWM, 8-bit
+  TCCR1B = (1<<WGM12); //Fast PWM, 8-bit
+  //TCCR1A |= (1<<COM1A1) // Clear OCnA/OCnB/OCnC on compare match when up-counting. Set OCnA/OCnB/OCnC on compare match when downcounting. (for FastPWM)
+
+  //for OC4D on pin D7
+  DDRD |= (1<<PD7);
+  TCCR4A = 0;
+  TCCR4B = 0;
+  TCCR4C = _BV(PWM4D); //Fast PWM: PWM4x == 0x1 && WGM41..40 ==0x00
+  TCCR4D = 0; //Fast PWM: PWM4x == 0x1 && WGM41..40 ==0x00
+  TCNT4 = 0;
+  OCR4C = 0xFF; //TOP value
+  OCR4D = 0;
+}
+
+inline void pwm_b5_on(void)
+{
+  TCCR1A |= (1<<COM1A1); // Clear OCnA/OCnB/OCnC on compare match when up-counting. Set OCnA/OCnB/OCnC on compare match when downcounting.
+  TCCR1B = (TCCR1B & 0xF8) | (1<<CS10); // enable timer clock, no prescaling
+}
+
+inline void pwm_d7_on(void)
+{
+  TCCR4B = (TCCR4B & 0xF0) | (1<<CS40); // enable timer clock, no prescaling
+  TCCR4C |=  (1<<COM4D1); // Clear OC4D on compare match when up-counting. Set when when TCNT4 == 0x000 (for FastPWM)
+}
+
+inline void pwm_b5_off(void)
+{
+  TCCR1A &= ~((1<<COM1A1) | (1<<COM1A0)); //normal port operation
+  TCCR1B = (TCCR1B & 0xF8);  //no clock source, timer stopped
+  TCNT1 = 0;
+  PORTB &= ~(1 << PB5);  //set pin to LOW (otherwise it will remain in state since last pwm toggle)
+}
+
+inline void pwm_d7_off(void)
+{
+  TCCR4B = (TCCR4B & 0xF0);  //no clock source, timer stopped
+  TCCR4C &=  ~(_BV(COM4D1) | _BV(COM4D0)); //normal port operation
+  TCNT4 = 0;
+  PORTD &= ~(1 << PD7);  //set pin to LOW (otherwise it will remain in state since last pwm toggle)
+}
+
+void pwm_b5_set(uint8_t val)
+{
+  if (val > 0)
+    pwm_b5_on();
+  else
+    pwm_b5_off();
+  PWMB5_VAL = val;
+}
+
+void pwm_d7_set(uint8_t val)
+{
+  if (val > 0)
+    pwm_d7_on();
+  else
+    pwm_d7_off();
+  PWMD7_VAL = val;
+}
+
+inline void pwm_b5_inc(void)
+{
+  if(PWMB5_VAL < 255)
+    PWMB5_VAL++;
+}
+
+inline void pwm_b5_dec(void)
+{
+  if(PWMB5_VAL > 0)
+    PWMB5_VAL--;
+}