From e971b58770e16921fab0d94fcca8be4ff0a057f5 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Thu, 22 Nov 2012 00:34:48 +0100
Subject: [PATCH] pwmled: regulation using sum of differences

---
 firmware/pwmled.c | 72 +++++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 31 deletions(-)

diff --git a/firmware/pwmled.c b/firmware/pwmled.c
index 90eb870..b76f219 100644
--- a/firmware/pwmled.c
+++ b/firmware/pwmled.c
@@ -61,6 +61,7 @@ static unsigned char pwmled_mode[N_PWMLEDS];
 static unsigned char pwmled_mode_set[N_PWMLEDS];
 
 static uint16_t pwm_probes[N_PWMLEDS];
+static int16_t differences[N_PWMLEDS];
 
 static void start_probing(unsigned char n)
 {
@@ -80,6 +81,7 @@ void pwmled_init()
 	}
 
 	for (i = 0; i < N_PWMLEDS; i++) {
+		differences[i] = 0;
 		start_probing(i);
 	}
 }
@@ -112,14 +114,7 @@ void pwmled_set_mode(unsigned char n, unsigned char mode)
 	log_byte(n);
 	log_byte(mode);
 #endif
-
-	if (mode == 0) {
-		pwm_off(n);
-		pwmled_state[n] = ST_OFF;
-		return;
-	}
-
-	if (mode <= N_PWMLED_MODES) {
+	if (mode > 0 && mode <= N_PWMLED_MODES) {
 		uint16_t pwmval;
 		mode--;
 		pwmval = pwm_vals[n*N_PWMLED_MODES+mode];
@@ -130,6 +125,10 @@ void pwmled_set_mode(unsigned char n, unsigned char mode)
 		pwmled_state[n] = ST_ON;
 		pwmled_mode[n] = mode;
 		pwmled_mode_set[n] = 1;
+		differences[n] = 0;
+	} else {
+		pwm_off(n);
+		pwmled_state[n] = ST_OFF;
 	}
 }
 
@@ -203,10 +202,10 @@ static void inline probing_adc(unsigned char n, uint16_t adcval)
 static void inline on_adc(unsigned char n, uint16_t adcval)
 {
 	unsigned char mode = pwmled_mode[n];
-	uint16_t adc_exp     =  adc_vals[n*N_PWMLED_MODES+mode];
-	uint16_t *pwm_p      = &pwm_vals[n*N_PWMLED_MODES+mode];
-	uint16_t old_pwm     = *pwm_p;
-	uint16_t new_pwm = old_pwm;
+	uint16_t adc_exp   =  adc_vals[n*N_PWMLED_MODES+mode];
+	uint16_t *pwm_p    = &pwm_vals[n*N_PWMLED_MODES+mode];
+	int16_t old_pwm    = *pwm_p;
+	int16_t new_pwm    = old_pwm;
 
 #if 0
 	log_byte(0xF5);
@@ -214,45 +213,56 @@ static void inline on_adc(unsigned char n, uint16_t adcval)
 	log_word(adcval);
 #endif
 
+
 	if (pwmled_mode_set[n]) { // ignore the first reading
 		pwmled_mode_set[n] = 0;
 		return;
 	}
 
-	// FIXME: running average?
-	if (2*adcval > 5*adc_exp) { // >2.5x expected, lower significantly
-		new_pwm = 2*old_pwm/3;
-	} else if (3*adcval > 4*adc_exp) { // >1.33x expected, lower a bit
-		new_pwm = old_pwm - 1;
-	} else if (4*adcval < 3*adc_exp) { // 0.75x expected, raise a bit
-		new_pwm = old_pwm + 1;
-	}
+	differences[n] += adcval;
+	differences[n] -= adc_exp;
 
-	// FIXME: better disconnect detection
-	if (new_pwm > pwm_max[n]) { // FIXME: disconnected?
+	if (differences[n] > 16)
+		new_pwm -= 2;
+	else if (differences[n] > 4)
+		new_pwm--;
+	else if (differences[n] < -16)
+		new_pwm += 2;
+	else if (differences[n] < -4)
+		new_pwm++;
+	// new_pwm -= differences[n] >> 3;
+
+	if (new_pwm == old_pwm)
+		return;
+
+	differences[n] = 0;
+
+	if (new_pwm > (int16_t)pwm_max[n]) {
+		// FIXME: disconnected?
 		new_pwm = pwm_max[n];
 	}
-	if (new_pwm < 2) { // short-circuit?
-		new_pwm = 2;
+
+	if (new_pwm < 1) {
+		// FIXME: short-circuit?
+		new_pwm = 1;
 	}
 
-	if (new_pwm != old_pwm) {
-		*pwm_p = new_pwm;
-		pwm_set(n, new_pwm);
-#if 0
-		log_byte(0xF9);
+	*pwm_p = new_pwm;
+	pwm_set(n, new_pwm);
+
+	if (jiffies > 500 && n == 1) {
+		log_byte(adcval & 0xFF);
 		log_byte(new_pwm);
-#endif
 	}
 }
 
 void pwmled_adc(unsigned char n, uint16_t adcval)
 {
 	unsigned char i, probing;
+
 	switch (pwmled_state[n]) {
 	case ST_PROBING:
 		probing_adc(n, adcval);
-
 #if 1
 		probing = 0;
 		for (i = 0; i < N_PWMLEDS; i++)
-- 
2.39.3