X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=bike-lights.git;a=blobdiff_plain;f=firmware%2Fpwm.c;h=27c8d0d0187d6e9a3f3e2a78448aefa7f0438843;hp=d68eeb2c3fdf370f69f32a8aa10b1afd68ff48a9;hb=65c3ad96cf307c3b77b36e6f6a2af5201c213a3c;hpb=7f7665a5234d4d5cbd94fed9be55862772f3dc12

diff --git a/firmware/pwm.c b/firmware/pwm.c
index d68eeb2..27c8d0d 100644
--- a/firmware/pwm.c
+++ b/firmware/pwm.c
@@ -1,5 +1,6 @@
 #include <avr/io.h>
 #include <avr/interrupt.h>
+#include <avr/power.h>
 #include <util/delay.h>
 #include <util/atomic.h>
 
@@ -7,12 +8,15 @@
 
 #define PWM_STEP_SHIFT 2 /* sub-LSB precision */
 #define PWM_TOP (((PWM_MAX) + (4 << (PWM_STEP_SHIFT))) >> (PWM_STEP_SHIFT))
-#if PWM_TOP > 0x1FF
+#if PWM_TOP > 0x3FF
 #error PWM_TOP too high
 #endif
 
+volatile unsigned char channels_running;
+
 static uint16_t pwm[N_PWMLEDS];
 static volatile unsigned char step;
+static unsigned char pll_enabled;
 
 static void enable_pll()
 {
@@ -24,6 +28,8 @@ static void enable_pll()
 	while ((PLLCSR & _BV(PLOCK)) == 0)
 		;
 	PLLCSR |= _BV(PCKE);
+
+	pll_enabled = 1;
 }
 
 void init_pwm()
@@ -31,12 +37,12 @@ void init_pwm()
 	int i;
 
 	step = 0;
+	channels_running = 0;
+	pll_enabled = 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);
 	// PWM channels A and B are not
@@ -76,6 +82,7 @@ void pwm_off(unsigned char n)
 {
 	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 		pwm[n] = 0;
+		channels_running &= ~(1 << n);
 
 		switch (n) {
 		case 0: DDRB &= ~_BV(PB1); break;
@@ -119,6 +126,12 @@ void pwm_set(unsigned char n, uint16_t stride)
 
 	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
 		pwm[n] = stride;
+		channels_running |= (1 << n);
+
+		if (!pll_enabled) {
+			power_timer1_enable();
+			enable_pll();
+		}
 
 		pwm_update_hw(n);
 
@@ -142,3 +155,15 @@ void pwm_timer()
 			pwm_update_hw(i);
 }
 
+void pwm_disable_if_not_needed()
+{
+	if (channels_running)
+		return;
+
+	pll_enabled = 0;
+	DDRB &= ~(_BV(PB1) | _BV(PB3) | _BV(PB5));
+	PLLCSR &= ~(_BV(PLLE) | _BV(PCKE));
+
+	power_timer1_disable();
+}
+