pwm: 16-bit pwm and adc values

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

diff --git a/firmware/pwm.c b/firmware/pwm.c
index 4eb2f83183a1ee411176b58815180afe12d786d0..10c03ba700677a9141ad165ef761357a64f0d3d1 100644 (file)
--- a/firmware/pwm.c
+++ b/firmware/pwm.c
@@ -4,7 +4,7 @@
 
 #include "lights.h"
 
-#define PWM_MAX 0x0FF
+#define PWM_MAX 0x1FF
 
 void init_pwm()
 {
@@ -23,10 +23,11 @@ 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;
@@ -45,26 +46,34 @@ void pwm_off(unsigned char n)
        }
 }
 
-void pwm_set(unsigned char n, unsigned char stride)
+void pwm_set(unsigned char n, uint16_t stride)
 {
-       TC1H = 0x00;
+       unsigned char hi, lo;
+
+       if (stride > PWM_MAX)
+               stride = PWM_MAX;
+
+       if (n == 2)
+               stride = PWM_MAX - stride;
+
+       hi = stride >> 8;
+       lo = stride & 0xFF;
+
        switch (n) {
        case 0:
-               OCR1A = stride;
+               TC1H = hi;
+               OCR1A = lo;
                DDRB |= _BV(PB1);
                break;
-       case 1: OCR1B = stride;
+       case 1:
+               TC1H = hi;
+               OCR1B = lo;
                DDRB |= _BV(PB3);
                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;
-                       DDRB |= _BV(PB5);
-               }
+       case 2:
+               TC1H = hi;
+               OCR1D = lo;
+               DDRB |= _BV(PB5);
                break;
        }
 }