From bdb1590839e5962741140ce2f4db722219f9d6f6 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Fri, 26 Feb 2021 19:16:55 +0100
Subject: Add SCD4x driver and datalog integration

---
 Makefile                   | 18 ++++++++++++++++++
 include/driver/scd4x.h     | 34 ++++++++++++++++++++++++++++++++++
 src/app/datalogger/main.cc | 18 ++++++++++++++++++
 src/driver/scd4x.cc        | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 110 insertions(+)
 create mode 100644 include/driver/scd4x.h
 create mode 100644 src/driver/scd4x.cc

diff --git a/Makefile b/Makefile
index d45e8be..4f518ae 100644
--- a/Makefile
+++ b/Makefile
@@ -108,6 +108,14 @@ ifneq ($(findstring sharp96,${drivers}), )
 	CONFIG_driver_sharp96 = y
 endif
 
+ifneq ($(findstring tsl2591,${drivers}), )
+	CONFIG_driver_tsl2591 = y
+endif
+
+ifneq ($(findstring scd4x,${drivers}), )
+	CONFIG_driver_scd4x = y
+endif
+
 ifneq ($(findstring resistive_load,${drivers}), )
 	CONFIG_driver_resistive_load = y
 endif
@@ -192,6 +200,16 @@ ifdef CONFIG_driver_mmsubstate
 	COMMON_FLAGS += -DDRIVER_MMSUBSTATE
 endif
 
+ifdef CONFIG_driver_tsl2591
+	CXX_TARGETS += src/driver/tsl2591.cc
+	COMMON_FLAGS += -DDRIVER_TSL2591
+endif
+
+ifdef CONFIG_driver_scd4x
+	CXX_TARGETS += src/driver/scd4x.cc
+	COMMON_FLAGS += -DDRIVER_SCD4X
+endif
+
 ifdef CONFIG_driver_nrf24l01
 	CXX_TARGETS += src/driver/nrf24l01.cc
 	ifeq (${arch_dir}, msp430fr5994lp)
diff --git a/include/driver/scd4x.h b/include/driver/scd4x.h
new file mode 100644
index 0000000..19ba20d
--- /dev/null
+++ b/include/driver/scd4x.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2021 Daniel Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#ifndef SCD4x_H
+#define SCD4x_H
+
+class SCD4x {
+	private:
+		SCD4x(const SCD4x &copy);
+		unsigned char const address = 0x62;
+		unsigned char txbuf[2];
+		unsigned char rxbuf[9];
+
+	public:
+		SCD4x() {}
+
+		unsigned short co2;
+		unsigned short rawTemperature;
+		unsigned short rawHumidity;
+
+		void start();
+		void stop();
+
+		void startLowPower();
+		void stopLowPower();
+
+		void read();
+};
+
+extern SCD4x scd4x;
+
+#endif
diff --git a/src/app/datalogger/main.cc b/src/app/datalogger/main.cc
index 8740035..46ff6b0 100644
--- a/src/app/datalogger/main.cc
+++ b/src/app/datalogger/main.cc
@@ -45,6 +45,9 @@
 #ifdef DRIVER_TSL2591
 #include "driver/tsl2591.h"
 #endif
+#ifdef DRIVER_SCD4X
+#include "driver/scd4x.h"
+#endif
 
 void loop(void)
 {
@@ -136,6 +139,17 @@ void loop(void)
 	kout << dec << "TSL2591 CH0: " << tsl2591.ch0 << " / CH1: " << tsl2591.ch1;
 	kout << hex << "   (status: 0x" << tsl2591.getStatus() << ")" << endl;
 #endif
+
+#ifdef DRIVER_SCD4X
+	scd4x.read();
+	kout << dec << "CO₂: " << scd4x.co2 << " ppm" << endl;
+	kout << "Temperature: ";
+	kout.printf_float(((175.0 * scd4x.rawTemperature) / 65536) - 45);
+	kout << " °c" << endl;
+	kout << "Humidity: ";
+	kout.printf_float((100.0 * scd4x.rawHumidity) / 65536);
+	kout << " %" << endl;
+#endif
 }
 
 int main(void)
@@ -224,6 +238,10 @@ int main(void)
 	tsl2591.init();
 #endif
 
+#ifdef DRIVER_SCD4X
+	scd4x.start();
+#endif
+
 	arch.idle_loop();
 
 	return 0;
diff --git a/src/driver/scd4x.cc b/src/driver/scd4x.cc
new file mode 100644
index 0000000..c0901e8
--- /dev/null
+++ b/src/driver/scd4x.cc
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2021 Daniel Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include "driver/scd4x.h"
+#include "driver/gpio.h"
+#if defined(MULTIPASS_ARCH_HAS_I2C) && !defined(DRIVER_SOFTI2C)
+#include "driver/i2c.h"
+#else
+#include "driver/soft_i2c.h"
+#endif
+
+void SCD4x::start()
+{
+	txbuf[0] = 0x21;
+	txbuf[1] = 0xb1;
+	i2c.xmit(address, 2, txbuf, 0, rxbuf);
+}
+
+void SCD4x::stop()
+{
+	txbuf[0] = 0x3f;
+	txbuf[1] = 0x86;
+	i2c.xmit(address, 2, txbuf, 0, rxbuf);
+}
+
+void SCD4x::read()
+{
+	txbuf[0] = 0xec;
+	txbuf[1] = 0x05;
+
+	if (i2c.xmit(address, 1, txbuf, 9, rxbuf) == 0) {
+		co2 = (rxbuf[0] << 8) + rxbuf[1];
+		rawTemperature = ((rxbuf[3] << 8) + rxbuf[4]);
+		rawHumidity = (rxbuf[6] << 8) + rxbuf[7];
+	}
+}
+
+SCD4x scd4x;
-- 
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