Poll ADC mode bit until conversion has finished

src/bus/i2c.c

@@ -21,6 +21,7 @@
 
 // TODO: Error handling and recovery besides watchdog timer.
 // TODO: Add more documentation from the atmel data sheet.
+// TODO: ADS1115 continuous mode instead of single-shot?
 // TODO: Implement TWI_vect ISR? This may not actually be
 // much better than the blocking approach.
 
@@ -31,6 +32,7 @@ static void  I2C_AHT20_Trigger(void);
 
 static int   I2C_ADS1115_WriteRegister(byte reg, word data);
 static word  I2C_ADS1115_ReadRegister(byte reg);
+static bool  I2C_ADS1115_IsReady(void);
 
 int I2C_Init(void)
 {
@@ -464,10 +466,21 @@ static word I2C_ADS1115_ReadRegister(byte reg)
 	return data[0] << 8 | data[1];
 }
 
+static bool I2C_ADS1115_IsReady(void)
+{
+	word reg;
+
+	Sleep(20);
+
+	reg = I2C_ADS1115_ReadRegister(0x01);
+
+	return reg & BIT(15);
+}
+
 word I2C_ADS1115_Read(int channel)
 {
 	word config;
-	word rate, gain, mux, os;
+	word os, mode, rate, gain, mux;
 
 	// Operational status or single-shot conversion
 	// start: This bit determines the operational
@@ -482,7 +495,15 @@ word I2C_ADS1115_Read(int channel)
 	// 0 : Device is performing a conversion
 	// 1 : Device is not performing a conversion
 
-	os = 0x8000; // Start single  |  10000000 00000000
+	os = 0x8000; // Start single   |  10000000 00000000
+
+	// Device operating mode: This bit controls the
+	// operating mode.
+
+	// 0 : Continuous-conversion mode
+	// 1 : Single-shot mode or power-down state
+
+	mode = 0x0100; // Single-shot  |  00000001 00000000
 
 	// Data rate: These bits control the data rate setting.
 
@@ -495,7 +516,7 @@ word I2C_ADS1115_Read(int channel)
 	// 110  |  475 SPS
 	// 111  |  860 SPS
 
-	rate = 0x0080; // 128 SPS     |  00000000 10000000
+	rate = 0x0080; // 128 SPS      |  00000000 10000000
 
 	// Programmable gain amplifier configuration: These
 	// bits set the FSR of the programmable gain amplifier.
@@ -509,7 +530,7 @@ word I2C_ADS1115_Read(int channel)
 	// 110  |  ±0.256 V
 	// 111  |  ±0.256 V
 
-	gain = 0x0000; // 6.144 V     |  00000100 00000000
+	gain = 0x0000; // 6.144 V      |  00000100 00000000
 
 	// Input multiplexer configuration: These bits
 	// configure the input multiplexer.
@@ -525,18 +546,21 @@ word I2C_ADS1115_Read(int channel)
 
 	mux = 0;
 	if (channel == ADS01)
-		mux = 0x4000; //     |  01000000 00000000
+		mux = 0x4000; //      |  01000000 00000000
 	else if (channel == ADS02)
-		mux = 0x5000; //     |  01010000 00000000
+		mux = 0x5000; //      |  01010000 00000000
 	else if (channel == ADS03)
-		mux = 0x6000; //     |  01100000 00000000
+		mux = 0x6000; //      |  01100000 00000000
 	else if (channel == ADS04)
-		mux = 0x7000; //     |  01110000 00000000
+		mux = 0x7000; //      |  01110000 00000000
 
-	// Single-shot conversion, active low, continous mode
-	config = os | rate | gain | mux;
+	// Single-shot conversion, active low
+	config = os | mode | rate | gain | mux;
 	I2C_ADS1115_WriteRegister(0x01, config);
 
+	// Wait until conversion finished
+	while (!I2C_ADS1115_IsReady());
+
 	return I2C_ADS1115_ReadRegister(0x00);
 }
 

src/main.c

@@ -60,7 +60,7 @@ static int Init(void)
 	PWM_Init();
 
 	MOS_Enable(MOS03); // Lights
-	// MOS_Enable(MOS01); // Peltier
+	MOS_Enable(MOS01); // Peltier
 	// MOS_Disable(MOS02); // Heating
 
 	// Only FAN01 and FAN02 are receiving the correct
@@ -73,7 +73,7 @@ static int Init(void)
 	// complicated so it might be worth it to switch to
 	// something like an ATmega328PB.
 
-	PWM_SetValue(FAN01, 50); // Fan Peltier Hot side
+	PWM_SetValue(FAN01, 20); // Fan Peltier Hot side
 	PWM_SetValue(FAN02, 50); // Fan Peltier Cold Side
 	// PWM_SetValue(FAN03, 20); // Fan Heating
 
@@ -99,7 +99,7 @@ static void Update(void)
 	float temp[3], rh[3];
 	float adct[3];
 
-	// Info("Reading sensor values...");
+	Info("Reading sensor values...");
 
 	I2C_SetChannel(AHT01);
 	I2C_AHT20_Read(&temp[0], &rh[0]);
@@ -110,18 +110,13 @@ static void Update(void)
 	I2C_SetChannel(AHT03);
 	I2C_AHT20_Read(&temp[2], &rh[2]);
 
-	Sleep(200); // FIXME: Poll config register until BIT(15) == 1
 	adct[0] = I2C_ADS1115_ReadThermistor(ADS01);
-	Sleep(200); // FIXME: Remove me - see above.
 	adct[1] = I2C_ADS1115_ReadThermistor(ADS02);
-	Sleep(200); // FIXME: Remove me - see above.
 	adct[2] = I2C_ADS1115_ReadThermistor(ADS03);
 
-	Info("TEMP0=%.2fC, RH0=%.2f%%", temp[0], rh[0]);
-	Info("TEMP1=%.2fC, RH1=%.2f%%", temp[1], rh[1]);
-	Info("TEMP2=%.2fC, RH2=%.2f%%", temp[2], rh[2]);
-	Info("ADCT1=%.2fC, ADCT2=%.2fC", adct[0], adct[1]);
-	Info("ADCT3=%.2fC", adct[2]);
+	Info("TEMP1=%.2fC, RH1=%.2f%% ADCT1=%.2fC", temp[0], rh[0], adct[0]);
+	Info("TEMP2=%.2fC, RH2=%.2f%% ADCT2=%.2fC", temp[1], rh[1], adct[1]);
+	Info("TEMP3=%.2fC, RH3=%.2f%% ADCT3=%.2fC", temp[2], rh[2], adct[2]);
 
 	// TODO: Implement state machine