2 #include <avr/interrupt.h>
3 #include <util/delay.h>
7 static uint16_t pwm[N_PWMLEDS];
8 static volatile unsigned char step;
16 for (i = 0; i < N_PWMLEDS; i++)
22 /* Synchronize to the phase lock */
24 while ((PLLCSR & _BV(PLOCK)) == 0)
28 // PWM channel D is inverted, ...
29 TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D);
30 // PWM channels A and B are not
31 TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B);
33 TCCR1B = _BV(CS10); // no clock prescaling
36 OCR1C = PWM_MAX & 0xFF; // TOP value
38 TC1H = PWM_MAX >> 8; // PWM3 is inverted
39 OCR1D = PWM_MAX & 0xFF;
42 OCR1B = OCR1A = 0; // initial stride is 0
44 DDRB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // tristate it
45 PORTB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // set to zero
52 for (i = 0; i < N_PWMLEDS; i++)
55 DDRB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 ));
56 TCCR1D = TCCR1C = TCCR1B = TCCR1A = 0;
61 void pwm_off(unsigned char n)
66 case 0: DDRB &= ~_BV(PB1); break;
67 case 1: DDRB &= ~_BV(PB3); break;
68 case 2: DDRB &= ~_BV(PB5); break;
72 static void pwm_update_hw(unsigned char n)
75 uint16_t stride = (pwm[n] + step) >> PWM_STEP_SHIFT;
78 stride = PWM_MAX - stride;
102 void pwm_set(unsigned char n, uint16_t stride)
104 if (((stride + (1 << PWM_STEP_SHIFT)) >> PWM_STEP_SHIFT) >= PWM_MAX)
105 stride = PWM_MAX << PWM_STEP_SHIFT;
115 if (++step >= (1 << PWM_STEP_SHIFT))
118 for (i = 0; i < N_PWMLEDS; i++)
124 static void inline pwm_handler()
129 TIMSK &= ~_BV(TOIE1);