pwm.c: PLL clock enabling code

[bike-lights.git] / firmware / pwm.c

diff --git a/firmware/pwm.c b/firmware/pwm.c
index 02992e9a012dcdd6a4451aaf0dbe3e58c1186571..3ef52c3fd436bc733ab7567b722487981fd3c133 100644 (file)
--- a/firmware/pwm.c
+++ b/firmware/pwm.c
@@ -4,18 +4,31 @@
 
 #include "lights.h"
 
-#define PWM_MAX 0x0FF
+static uint16_t pwm[N_PWMLEDS];
+static volatile unsigned char step;
 
-void init_pwm()
+static void enable_pll()
 {
        /* Async clock */
        PLLCSR = _BV(PLLE);
 
        /* Synchronize to the phase lock */
-       _delay_ms(1);
+       _delay_us(100);
        while ((PLLCSR & _BV(PLOCK)) == 0)
                ;
        PLLCSR |= _BV(PCKE);
+}
+
+void init_pwm()
+{
+       int i;
+
+       step = 0;
+
+       for (i = 0; i < N_PWMLEDS; i++)
+               pwm[i] = 0;
+
+       enable_pll();
 
        // PWM channel D is inverted, ...
        TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D);
@@ -23,10 +36,11 @@ void init_pwm()
        TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B);
        TCCR1D = 0;
        TCCR1B = _BV(CS10);                     // no clock prescaling
+
        TC1H = PWM_MAX >> 8;
        OCR1C = PWM_MAX & 0xFF;                         // TOP value
 
-       TC1H = PWM_MAX >> 8;
+       TC1H = PWM_MAX >> 8;            // PWM3 is inverted
        OCR1D = PWM_MAX & 0xFF;
 
        TC1H = 0x00;
@@ -36,17 +50,25 @@ void init_pwm()
        PORTB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // set to zero
 }
 
-void pwm_on(unsigned char n)
+void susp_pwm()
 {
-       switch (n) {
-       case 0: DDRB |= _BV(PB1); break;
-       case 1: DDRB |= _BV(PB3); break;
-       case 2: DDRB |= _BV(PB5); break;
-       }
+       unsigned char i;
+
+       for (i = 0; i < N_PWMLEDS; i++)
+               pwm[i] = 0;
+
+       DDRB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 ));
+       TCCR1D = TCCR1C = TCCR1B = TCCR1A = 0;
+       TIMSK = 0;
+       TIFR = 0;
+
+       PLLCSR &= ~(_BV(PLLE) | _BV(PCKE));
 }
 
 void pwm_off(unsigned char n)
 {
+       pwm[n] = 0;
+
        switch (n) {
        case 0: DDRB &= ~_BV(PB1); break;
        case 1: DDRB &= ~_BV(PB3); break;
@@ -54,24 +76,57 @@ void pwm_off(unsigned char n)
        }
 }
 
-void pwm_set(unsigned char n, unsigned char stride)
+static void pwm_update_hw(unsigned char n)
 {
-       TC1H = 0x00;
+       unsigned char hi, lo;
+       uint16_t stride = (pwm[n] + step) >> PWM_STEP_SHIFT;
+
+       if (n == 2)
+               stride = PWM_MAX - stride;
+
+       hi = stride >> 8;
+       lo = stride & 0xFF;
+
        switch (n) {
-       case 0: OCR1A = stride; break;
-       case 1: OCR1B = stride; break;
-       case 2: {
-                       uint16_t s16 = PWM_MAX - (uint16_t)stride;
-                       volatile unsigned char hi, lo;
-                       hi = s16 >> 8;
-                       lo = s16 & 0xFF;
-                       TC1H = hi;
-                       OCR1D = lo;
-               }
+       case 0:
+               TC1H = hi;
+               OCR1A = lo;
+               DDRB |= _BV(PB1);
+               break;
+       case 1:
+               TC1H = hi;
+               OCR1B = lo;
+               DDRB |= _BV(PB3);
+               break;
+       case 2:
+               TC1H = hi;
+               OCR1D = lo;
+               DDRB |= _BV(PB5);
                break;
        }
 }
 
+void pwm_set(unsigned char n, uint16_t stride)
+{
+       if (((stride + (1 << PWM_STEP_SHIFT)) >> PWM_STEP_SHIFT) >= PWM_MAX)
+               stride = PWM_MAX << PWM_STEP_SHIFT;
+
+       pwm[n] = stride;
+       pwm_update_hw(n);
+}
+
+void pwm_timer()
+{
+       unsigned char i;
+
+       if (++step >= (1 << PWM_STEP_SHIFT))
+               step = 0;
+
+       for (i = 0; i < N_PWMLEDS; i++)
+               if (pwm[i])
+                       pwm_update_hw(i);
+}
+
 #if 0
 static void inline pwm_handler()
 {