From 6193f6a3200efa660bbbe406e317fe7fa0473de0 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Thu, 28 Mar 2013 19:48:01 +0100
Subject: [PATCH] Timer-initiated ADC

Run ADC synchronously with timer IRQ. This partially reverts
commit 210916486d18b3dc976c65c7b01b44bca446d856 in order to
prepare for selectively enabling and disabling ADC channels.
---
 firmware/adc.c    | 16 +++++++++++++---
 firmware/lights.h |  1 +
 firmware/tmr.c    |  2 ++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/firmware/adc.c b/firmware/adc.c
index 02af6b3..f55a427 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -65,11 +65,13 @@ static void setup_mux(unsigned char n)
 
 static void start_next_adc()
 {
-	if (current_adc > 0)
+	if (current_adc > 0) {
 		current_adc--;
-	else
+	} else {
 		// TODO: kick the watchdog here.
-		current_adc = NUM_ADCS-1;
+		current_adc = NUM_ADCS;
+		return;
+	}
 
 	adc_sum = 0;
 	// we use the last iteration of zero_count to set up the MUX
@@ -96,6 +98,14 @@ static void start_next_adc()
 	ADCSRA |= _BV(ADSC);
 }
 
+void timer_start_adcs()
+{
+	if (current_adc == NUM_ADCS) // Don't start if in progress
+		start_next_adc();
+	else
+		log_byte(0x99); // overrun
+}
+
 /*
  * Single synchronous ADC conversion.
  * Has to be called with IRQs disabled (or with the ADC IRQ disabled).
diff --git a/firmware/lights.h b/firmware/lights.h
index 8fce475..2eb1f09 100644
--- a/firmware/lights.h
+++ b/firmware/lights.h
@@ -28,6 +28,7 @@ void inline log_word(uint16_t word) { }
 #define PWMLED_ADC_SHIFT 3 /* 1<<3 measurements per single callback */
 void init_adc();
 void susp_adc();
+void timer_start_adcs();
 
 /* pwm.c */
 /*
diff --git a/firmware/tmr.c b/firmware/tmr.c
index f0d7d93..37b240b 100644
--- a/firmware/tmr.c
+++ b/firmware/tmr.c
@@ -36,5 +36,7 @@ ISR(TIMER0_COMPA_vect)
 		patterns_next_tick();
 		pattern_div = PATTERN_DIV;
 	}
+
+	timer_start_adcs();
 }
 
-- 
2.39.3