From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Fri, 31 Jan 2014 16:32:05 +0000 (+0100)
Subject: Status LED visual feedback for buttons and battery
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=heater.git;a=commitdiff_plain;h=d3b9a34d6b153bd04e7d233c2e2bbcecc70a6fa5

Status LED visual feedback for buttons and battery
---

diff --git a/firmware/main.c b/firmware/main.c
index d35fb21..76bed47 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -33,10 +33,10 @@
  * Status LED:
  * When powering up by a button press, the LED goes on to provide a visual
  * feedback, and is switched off after the button is released.
- * TODO: After a button press, the # of blinks of the LED reflects the
+ * After a button press, the # of blinks of the LED reflects the
  * chosen output power level for some time. Afterwards, it displays
  * the battery level.
- * TODO: When the battery is completely exhausted, the output power is switched
+ * When the battery is completely exhausted, the output power is switched
  * off, the LED keeps blinking for some time, and then the whole system is
  * switched off to avoid deep discharge of the battery.
  *
@@ -106,6 +106,10 @@ static unsigned char power_levels[] = {
 #define N_POWER_LEVELS	(sizeof(power_levels) / sizeof(power_levels[0]))
 
 static unsigned char power_level = 0; // selected power level
+static unsigned char power_level_changed; // for visual feedback
+
+#define LED_PWRCHANGE_COUNT	3
+#define LED_BATTEMPTY_COUNT	60
 
 /* timing by WDT */
 static volatile unsigned char jiffies, next_clock_tick;
@@ -114,6 +118,7 @@ static volatile unsigned char jiffies, next_clock_tick;
 #define BUTTON_SHORT_MIN	1
 #define BUTTON_LONG_MIN		10
 
+
 /* ========= Analog to Digital Converter (battery voltage) ========== */
 static void adc_init()
 {
@@ -341,13 +346,78 @@ static void power_down()
 	hw_setup();
 }
 
+/* ============ Status LED blinking =================================== */
+static unsigned char blink_on_time, blink_off_time, n_blinks;
+static unsigned char blink_counter;
+
+static unsigned char battery_level()
+{
+	unsigned char i, adc8;
+
+	// NOTE: we use 8-bit value only, so we don't need lock to protect
+	// us against concurrently running ADC IRQ handler:
+	adc8 = batt_off >> 8;
+
+	for (i = 0; i < BATT_N_LEVELS; i++)
+		if (batt_levels[i] > adc8)
+			break;
+
+	return i;
+}
+
+static void status_led_next_pattern()
+{
+	static unsigned char battery_exhausted;
+
+	if (power_level_changed) {
+		power_level_changed--;
+		n_blinks = power_level + 1;
+	} else {
+		unsigned char b_level = battery_level();
+		if (b_level) {
+			battery_exhausted = 0;
+		} else if (battery_exhausted) {
+			if (!--battery_exhausted)
+				power_down();
+		} else {
+			battery_exhausted = LED_BATTEMPTY_COUNT;
+		}
+
+		n_blinks = b_level + 1;
+	}
+
+	blink_on_time = 2;
+	blink_off_time = 1;
+	blink_counter = 10;
+}
+
+static void timer_blink()
+{
+	if (blink_counter) {
+		blink_counter--;
+	} else if (!status_led_is_on()) {
+		status_led_on();
+		blink_counter = blink_on_time;
+	} else if (n_blinks) {
+		--n_blinks;
+		status_led_off();
+		blink_counter = blink_off_time;
+	} else {
+		status_led_next_pattern();
+	}
+}
+
 /* ======== Button press detection and  handling ===================== */
 static void button_pressed(unsigned char button, unsigned char long_press)
 {
 	// ignore simlultaneous button 1 and 2 press
+	// Note: we set power_level_changed after each button press,
+	// even when the power is at maximum, to provide visual feedback
+	// with status LED.
 	if (long_press) {
 		if (button == 1) {
 			power_down();
+			return;
 		} else if (button == 2) {
 			power_level = N_POWER_LEVELS-1;
 		}
@@ -357,6 +427,7 @@ static void button_pressed(unsigned char button, unsigned char long_press)
 				--power_level;
 			} else {
 				power_down();
+				return;
 			}
 		} else if (button == 2) {
 			if (power_level < N_POWER_LEVELS-1) {
@@ -364,6 +435,8 @@ static void button_pressed(unsigned char button, unsigned char long_press)
 			}
 		}
 	}
+	power_level_changed = LED_PWRCHANGE_COUNT;
+	status_led_next_pattern();
 }
 
 static unsigned char button_state, button_state_time;
@@ -397,52 +470,7 @@ static void timer_check_buttons()
 	button_state_time = 0;
 }
 
-/* ============ Status LED blinking =================================== */
-static unsigned char blink_on_time, blink_off_time, n_blinks;
-static unsigned char blink_counter;
-
-static unsigned char battery_level()
-{
-	unsigned char i, adc8;
-
-	// NOTE: we use 8-bit value only, so we don't need lock to protect
-	// us against concurrently running ADC IRQ handler:
-	adc8 = batt_off >> 8;
-
-	for (i = 0; i < BATT_N_LEVELS; i++)
-		if (batt_levels[i] > adc8)
-			break;
-
-	return i;
-}
-
-static void status_led_next_pattern()
-{
-
-	// for now, display the selected intensity
-	// n_blinks = power_level + 1;
-	n_blinks = battery_level() + 1;
-	blink_on_time = 0;
-	blink_off_time = 2;
-	blink_counter = 10;
-}
-
-static void timer_blink()
-{
-	if (blink_counter) {
-		blink_counter--;
-	} else if (status_led_is_on()) {
-		status_led_off();
-		blink_counter = blink_off_time;
-	} else if (n_blinks) {
-		--n_blinks;
-		status_led_on();
-		blink_counter = blink_on_time;
-	} else {
-		status_led_next_pattern();
-	}
-}
-
+/* ===================== Output power control ======================== */
 static void calculate_power_level()
 {
 	uint32_t pwm;