From dd42aebb16d297fbace1cab1155c1ff03eec981a Mon Sep 17 00:00:00 2001
From: BlackMark <me@blackmark.me>
Date: Mon, 6 Apr 2020 19:43:32 +0200
Subject: [PATCH] Make adc sampling interrupt driven

---
 fantemp/adc            |  2 +-
 fantemp/controller.cpp | 36 ++++++++++++++++++++++++++++--------
 fantemp/controller.hpp |  9 +++++++--
 fantemp/terminal.hpp   | 12 ++++++++++--
 fantemp/thermistor.hpp | 11 -----------
 5 files changed, 46 insertions(+), 24 deletions(-)

diff --git a/fantemp/adc b/fantemp/adc
index 5d38b97..7fe32b9 160000
--- a/fantemp/adc
+++ b/fantemp/adc
@@ -1 +1 @@
-Subproject commit 5d38b97254e271e3e0fb48739a927be6eae26a7f
+Subproject commit 7fe32b9717285aef6c264fb294f1d37f91075d1c
diff --git a/fantemp/controller.cpp b/fantemp/controller.cpp
index 06977d8..46f02f2 100644
--- a/fantemp/controller.cpp
+++ b/fantemp/controller.cpp
@@ -7,19 +7,28 @@ double Controller::m_adcSample;
 double Controller::m_resistance;
 double Controller::m_temperature;
 uint8_t Controller::m_fanSpeed;
+volatile uint32_t Controller::m_adcSampleSum;
+volatile bool Controller::m_adcSampleReady = false;
 
 void Controller::init()
 {
-	m_adcPin.init();
+	m_adcPin.init(sampleCallback);
 	pwm::init();
 	pwm::setDuty(100);
 }
 
 void Controller::callback()
 {
-	sample();
-	m_fanSpeed = mapTemperature(m_temperature);
-	pwm::setDuty(m_fanSpeed);
+	if (m_adcSampleReady) {
+		m_adcSample = static_cast<double>(m_adcSampleSum) / NUM_ADC_SAMPLES;
+		m_adcSampleReady = false;
+
+		m_resistance = m_thermistor.getResistance(m_adcSample);
+		m_temperature = m_thermistor.getTemperature(m_resistance);
+		m_fanSpeed = mapTemperature(m_temperature);
+
+		pwm::setDuty(m_fanSpeed);
+	}
 }
 
 uint8_t Controller::mapTemperature(double temperature)
@@ -35,9 +44,20 @@ uint8_t Controller::mapTemperature(double temperature)
 	return clamp<uint8_t>(fanSpeed, 0, 100);
 }
 
-void Controller::sample()
+void Controller::sampleCallback(const uint16_t &adcSample)
 {
-	m_adcSample = m_thermistor.sampleAdc(m_adcPin, 1000);
-	m_resistance = m_thermistor.getResistance(m_adcSample);
-	m_temperature = m_thermistor.getTemperature(m_resistance);
+	static uint32_t s_sampleSum = 0;
+	static auto s_sampleCounter = NUM_ADC_SAMPLES;
+
+	s_sampleSum += adcSample;
+
+	if (--s_sampleCounter <= 0) {
+		if (!m_adcSampleReady) {
+			m_adcSampleSum = s_sampleSum;
+			m_adcSampleReady = true;
+		}
+		// else lose this sample, which happens during long running commands like "curve", but has no impact
+		s_sampleSum = 0;
+		s_sampleCounter = NUM_ADC_SAMPLES;
+	}
 }
diff --git a/fantemp/controller.hpp b/fantemp/controller.hpp
index a4bb661..bdd1de4 100644
--- a/fantemp/controller.hpp
+++ b/fantemp/controller.hpp
@@ -20,12 +20,17 @@ class Controller {
 	static uint8_t mapTemperature(double temperature);
 
   private:
-	using adc_conf = adc::Config<adc::SingleMode>;
+	using adc_conf = adc::Config<adc::FreeRunningMode>;
 	static adc::Adc<adc_conf, io::P, io::P::C0> m_adcPin;
 
+	static constexpr auto NUM_ADC_SAMPLES = 1000;
+
+	static volatile uint32_t m_adcSampleSum;
+	static volatile bool m_adcSampleReady;
+
 	static Thermistor m_thermistor;
 
-	static void sample();
+	static void sampleCallback(const uint16_t &adcSample);
 
 	template <typename T>
 	static T clamp(double value, T lower, T upper)
diff --git a/fantemp/terminal.hpp b/fantemp/terminal.hpp
index 83b0e55..77d00e6 100644
--- a/fantemp/terminal.hpp
+++ b/fantemp/terminal.hpp
@@ -19,7 +19,7 @@ GF(CURVE_CMD, "curve");
 GF(MONITOR_CMD, "monitor");
 GF(BOOTLOADER_CMD, "bootloader");
 GF(VERSION_CMD, "version");
-GF(VERSION, "1.1");
+GF(VERSION, "1.2");
 
 static inline bool substringEquals(const char *str, const ::detail::FlashString *flashStr, const size_t &size)
 {
@@ -99,14 +99,17 @@ class Terminal {
 			m_serial << F("$ ");
 		}
 
-		if (m_state == State::MONITOR)
+		if (m_state == State::MONITOR && --m_monitorDelayCounter == 0) {
 			showState();
+			m_monitorDelayCounter = MONITOR_DELAY;
+		}
 	}
 
   private:
 	static constexpr auto INPUT_BUFFER_SIZE = 128;
 	static constexpr auto BACKSPACE = uint8_t{0x7f};
 	static constexpr auto CTRL_C = uint8_t{0x03};
+	static constexpr auto MONITOR_DELAY = 60000;
 
 	enum class State {
 		NONE,
@@ -117,6 +120,7 @@ class Terminal {
 	static char m_inputBuffer[INPUT_BUFFER_SIZE];
 	static uint16_t m_inputSize;
 	static State m_state;
+	static uint16_t m_monitorDelayCounter;
 
 	static void parseInput()
 	{
@@ -131,6 +135,7 @@ class Terminal {
 				printCurve();
 			} else if (substringEquals(m_inputBuffer, detail::MONITOR_CMD, m_inputSize)) {
 				m_state = State::MONITOR;
+				m_monitorDelayCounter = MONITOR_DELAY;
 			} else if (substringEquals(m_inputBuffer, detail::BOOTLOADER_CMD, m_inputSize)) {
 				handleBootloader();
 			} else if (substringEquals(m_inputBuffer, detail::VERSION_CMD, m_inputSize)) {
@@ -216,3 +221,6 @@ uint16_t Terminal<Uart>::m_inputSize = 0;
 
 template <class Uart>
 typename Terminal<Uart>::State Terminal<Uart>::m_state = State::NONE;
+
+template <class Uart>
+uint16_t Terminal<Uart>::m_monitorDelayCounter;
diff --git a/fantemp/thermistor.hpp b/fantemp/thermistor.hpp
index bb748a4..a542f7f 100644
--- a/fantemp/thermistor.hpp
+++ b/fantemp/thermistor.hpp
@@ -4,17 +4,6 @@
 
 class Thermistor {
   public:
-	template <typename Adc>
-	static double sampleAdc(Adc &adcPin, uint16_t numSamples = 100)
-	{
-		double samples = 0;
-
-		for (uint16_t i = 0; i < numSamples; ++i)
-			samples += adcPin.read();
-
-		return samples / numSamples;
-	}
-
 	static double getResistance(double adcSample);
 
 	static double getTemperature(double resistance);