From cb1c160753d04c7c9106284085b74dbf5248f92c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Mon, 4 Apr 2016 22:10:13 +0200
Subject: [PATCH] add battery voltage display on LED

---
 main.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/main.c b/main.c
index 08a1051..a2b2d57 100644
--- a/main.c
+++ b/main.c
@@ -399,7 +399,7 @@ int main(void)
 	adc_enable_discontinuous_mode_regular(ADC1, 1); // do only one conversion per sequence
 	adc_enable_external_trigger_regular(ADC1, ADC_CR2_EXTSEL_SWSTART); // use software trigger to start conversion
 	adc_power_on(ADC1); // switch on ADC
-	for (uint32_t i = 0; i < 800000; i++) { // wait t_stab for the ADC to stabilize
+	for (uint32_t i=0; i<800000; i++) { // wait t_stab for the ADC to stabilize
 		__asm__("nop");
 	}
 	adc_reset_calibration(ADC1); // remove previous non-calibration
@@ -422,6 +422,26 @@ int main(void)
 		printf("/!\\ low ");
 	}
 	printf("battery voltage: %.2fV\n", battery_voltage);
+	
+	// show voltage on LEDs
+	if (battery_voltage<2.4) { // low battery voltage
+		for (uint16_t led=0; led<2; led++) { // display red on 2 LEDs
+			clock_leds[led*3+0] = 0xff; // set red
+		}
+	} else if (battery_voltage>3.0) { // battery full
+		for (uint16_t led=0; led<WS2812B_LEDS; led++) { // display green on all LEDs
+			clock_leds[led*3+1] = 0xff; // set green
+		}
+	} else { // intermediate batter voltage
+		for (uint16_t led=0; led<(uint8_t)(WS2812B_LEDS*(battery_voltage-2.4)/0.6); led++) { // display blue on proportional LEDs
+			clock_leds[led*3+2] = 0xff; // set blue
+		}
+	}
+	clock_leds_set(); // set the colors of all LEDs
+	ws2812b_transmit(); // transmit set color
+	for (uint32_t i=0; i<10000000; i++) { // display for a small while
+		__asm__("nop");
+	}	
 
 	// now use interrupts to only measure ambient luminosity
 	channels[0] = PHOTORESISTOR_ADC_CHANNEL; // only measure ambient luminosity