Implement CPUTemperature() (#1225)

Author: tekka007

hal/architecture/AVR/MyHwAVR.cpp

@@ -334,7 +334,19 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127; // not implemented yet
+#if defined(__AVR_ATmega168A__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega328__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328BP__) || defined(__AVR_ATmega32U4__)
+	// Set the internal reference and mux.
+	ADMUX = (_BV(REFS1) | _BV(REFS0) | _BV(MUX3));
+	ADCSRA |= _BV(ADEN);  // enable the ADC
+	delay(20);            // wait for voltages to become stable.
+	ADCSRA |= _BV(ADSC);  // Start the ADC
+	// Wait until conversion done
+	while (bit_is_set(ADCSRA, ADSC));
+	// temperature is in degrees Celsius
+	return static_cast<int8_t>((ADCW - MY_AVR_TEMPERATURE_OFFSET) / MY_AVR_TEMPERATURE_GAIN);
+#else
+	return -127; // not available
+#endif
 }
 
 uint16_t hwFreeMem(void)

hal/architecture/AVR/MyHwAVR.h

@@ -43,6 +43,15 @@
 #define MY_DEBUGDEVICE MY_SERIALDEVICE
 #endif
 
+// AVR temperature calibration reference: http://ww1.microchip.com/downloads/en/AppNotes/Atmel-8108-Calibration-of-the-AVRs-Internal-Temperature-Reference_ApplicationNote_AVR122.pdf
+#ifndef MY_AVR_TEMPERATURE_OFFSET
+#define MY_AVR_TEMPERATURE_OFFSET (324.31f)
+#endif
+
+#ifndef MY_AVR_TEMPERATURE_GAIN
+#define MY_AVR_TEMPERATURE_GAIN (1.22f)
+#endif
+
 // Define these as macros to save valuable space
 #define hwDigitalWrite(__pin, __value) digitalWriteFast(__pin, __value)
 #define hwDigitalRead(__pin) digitalReadFast(__pin)

hal/architecture/ESP32/MyHwESP32.cpp

@@ -133,7 +133,9 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127; // not implemented yet
+	// CPU temperature in °C
+	return static_cast<int8_t>((temperatureRead() - MY_ESP32_TEMPERATURE_OFFSET) /
+	                           MY_ESP32_TEMPERATURE_GAIN);
 }
 
 uint16_t hwFreeMem(void)

hal/architecture/ESP32/MyHwESP32.h

@@ -55,6 +55,14 @@
 #define MY_DEBUGDEVICE MY_SERIALDEVICE
 #endif
 
+#ifndef MY_ESP32_TEMPERATURE_OFFSET
+#define MY_ESP32_TEMPERATURE_OFFSET (0.0f)
+#endif
+
+#ifndef MY_ESP32_TEMPERATURE_GAIN
+#define MY_ESP32_TEMPERATURE_GAIN (1.0f)
+#endif
+
 #define MY_EEPROM_SIZE 1024
 
 #define hwDigitalWrite(__pin, __value) digitalWrite(__pin, __value)

hal/architecture/ESP8266/MyHwESP8266.cpp

@@ -147,7 +147,7 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127;
+	return -127; // not available
 }
 
 uint16_t hwFreeMem(void)

hal/architecture/Linux/MyHwLinuxGeneric.cpp

@@ -149,7 +149,7 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127;
+	return -127;  // not implemented yet
 }
 
 uint16_t hwFreeMem(void)

hal/architecture/MyHwHAL.h

@@ -108,13 +108,14 @@ uint16_t hwCPUVoltage(void);
 uint16_t hwCPUFrequency(void);
 
 /**
- * Non-calibrated CPU temperature (if available)
- * @return CPU temperature in °C
+ * CPU temperature (if available)
+ * Adjust calibration parameters via MY_<ARCH>_TEMPERATURE_OFFSET and MY_<ARCH>_TEMPERATURE_GAIN
+ * @return CPU temperature in °C, -127 if not available
  */
 int8_t hwCPUTemperature(void);
 
 /**
- * Free memory
+ * Report free memory (if function available)
  * @return free memory in bytes
  */
 uint16_t hwFreeMem(void);

hal/architecture/SAMD/MyHwSAMD.cpp

@@ -73,6 +73,11 @@ bool hwInit(void)
 	while (!MY_SERIALDEVICE) {}
 #endif
 #endif
+
+	SYSCTRL->VREF.reg |= SYSCTRL_VREF_TSEN; // Enable the temperature sensor
+	while (ADC->STATUS.bit.SYNCBUSY ==
+	        1); // Wait for synchronization of registers between the clock domains
+
 	const uint8_t eepInit = eep.begin(MY_EXT_EEPROM_TWI_CLOCK, &Wire);
 #if defined(SENSEBENDER_GW_SAMD_V1)
 	// check connection to external EEPROM - only sensebender GW
@@ -178,7 +183,68 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127; // not implemented yet
+	// taken from https://github.com/arduino/ArduinoCore-samd/pull/277
+	// Set to 12 bits resolution
+	ADC->CTRLB.reg = ADC_CTRLB_RESSEL_12BIT | ADC_CTRLB_PRESCALER_DIV256;
+	syncADC();
+	// Ensure we are sampling slowly
+	ADC->SAMPCTRL.reg = ADC_SAMPCTRL_SAMPLEN(0x3f);
+	syncADC();
+	// Set ADC reference to internal 1v
+	ADC->INPUTCTRL.bit.GAIN = ADC_INPUTCTRL_GAIN_1X_Val;
+	ADC->REFCTRL.bit.REFSEL = ADC_REFCTRL_REFSEL_INT1V_Val;
+	syncADC();
+	// Select MUXPOS as temperature channel, and MUXNEG as internal ground
+	ADC->INPUTCTRL.bit.MUXPOS = ADC_INPUTCTRL_MUXPOS_TEMP_Val;
+	ADC->INPUTCTRL.bit.MUXNEG = ADC_INPUTCTRL_MUXNEG_GND_Val;
+	syncADC();
+	// Enable ADC
+	ADC->CTRLA.bit.ENABLE = 1;
+	syncADC();
+	// Start ADC conversion
+	ADC->SWTRIG.bit.START = 1;
+	// Clear the Data Ready flag
+	ADC->INTFLAG.reg = ADC_INTFLAG_RESRDY;
+	syncADC();
+	// Start conversion again, since The first conversion after the reference is changed must not be used.
+	ADC->SWTRIG.bit.START = 1;
+	// Wait until ADC conversion is done
+	while (!(ADC->INTFLAG.bit.RESRDY));
+	syncADC();
+	// Get result
+	// This is signed so that the math later is done signed
+	const int32_t adcReading = ADC->RESULT.reg;
+	// Clear result ready flag
+	ADC->INTFLAG.reg = ADC_INTFLAG_RESRDY;
+	syncADC();
+	// Disable ADC
+	ADC->CTRLA.bit.ENABLE = 0;
+	syncADC();
+	// Factory room temperature readings
+	const uint8_t roomInteger = (*(uint32_t *)FUSES_ROOM_TEMP_VAL_INT_ADDR &
+	                             FUSES_ROOM_TEMP_VAL_INT_Msk)
+	                            >> FUSES_ROOM_TEMP_VAL_INT_Pos;
+	const uint8_t roomDecimal = (*(uint32_t *)FUSES_ROOM_TEMP_VAL_DEC_ADDR &
+	                             FUSES_ROOM_TEMP_VAL_DEC_Msk)
+	                            >> FUSES_ROOM_TEMP_VAL_DEC_Pos;
+	const int32_t roomReading = ((*(uint32_t *)FUSES_ROOM_ADC_VAL_ADDR & FUSES_ROOM_ADC_VAL_Msk) >>
+	                             FUSES_ROOM_ADC_VAL_Pos);
+	const int32_t roomTemperature = 1000 * roomInteger + 100 * roomDecimal;
+	// Factory hot temperature readings
+	const uint8_t hotInteger = (*(uint32_t *)FUSES_HOT_TEMP_VAL_INT_ADDR & FUSES_HOT_TEMP_VAL_INT_Msk)
+	                           >>
+	                           FUSES_HOT_TEMP_VAL_INT_Pos;
+	const uint8_t hotDecimal = (*(uint32_t *)FUSES_HOT_TEMP_VAL_DEC_ADDR & FUSES_HOT_TEMP_VAL_DEC_Msk)
+	                           >>
+	                           FUSES_HOT_TEMP_VAL_DEC_Pos;
+	const int32_t hotReading = ((*(uint32_t *)FUSES_HOT_ADC_VAL_ADDR & FUSES_HOT_ADC_VAL_Msk) >>
+	                            FUSES_HOT_ADC_VAL_Pos);
+	const int32_t hotTemperature = 1000 * hotInteger + 100 * hotDecimal;
+	// Linear interpolation of temperature using factory room temperature and hot temperature
+	const int32_t temperature = roomTemperature + ((hotTemperature - roomTemperature) *
+	                            (adcReading - roomReading)) / (hotReading - roomReading);
+	return static_cast<int8_t>(((temperature / 1000) - MY_SAMD_TEMPERATURE_OFFSET) /
+	                           MY_SAMD_TEMPERATURE_GAIN);
 }
 
 

hal/architecture/SAMD/MyHwSAMD.h

@@ -35,6 +35,14 @@
 #define MY_DEBUGDEVICE MY_SERIALDEVICE
 #endif
 
+#ifndef MY_SAMD_TEMPERATURE_OFFSET
+#define MY_SAMD_TEMPERATURE_OFFSET (0.0f)
+#endif
+
+#ifndef MY_SAMD_TEMPERATURE_GAIN
+#define MY_SAMD_TEMPERATURE_GAIN (1.0f)
+#endif
+
 // defines for sensebender gw variant.h
 #define MY_EXT_EEPROM_I2C_ADDRESS	(0x50u)
 #define MY_EXT_EEPROM_SIZE			(kbits_512)

hal/architecture/STM32F1/MyHwSTM32F1.cpp

@@ -50,8 +50,6 @@ bool hwInit(void)
 	while (!MY_SERIALDEVICE) {}
 #endif
 #endif
-	adc_calibrate(ADC1);
-
 	if (EEPROM.init() == EEPROM_OK) {
 		uint16 cnt;
 		EEPROM.count(&cnt);
@@ -146,6 +144,7 @@ void hwRandomNumberInit(void)
 		seed ^= ( (newValue + hwMillis()) & 7) << i;
 	}
 	randomSeed(seed);
+	regs->CR2 &= ~ADC_CR2_TSVREFE; // disable VREFINT and temp sensor
 }
 
 bool hwUniqueID(unique_id_t *uniqueID)
@@ -159,7 +158,11 @@ uint16_t hwCPUVoltage(void)
 	adc_reg_map *regs = ADC1->regs;
 	regs->CR2 |= ADC_CR2_TSVREFE; // enable VREFINT and temp sensor
 	regs->SMPR1 =  ADC_SMPR1_SMP17; // sample rate for VREFINT ADC channel
-	return 1200 * 4096 / adc_read(ADC1, 17);
+	adc_calibrate(ADC1);
+
+	const uint16_t vdd = adc_read(ADC1, 17);
+	regs->CR2 &= ~ADC_CR2_TSVREFE; // disable VREFINT and temp sensor
+	return 1200 * 4096 / vdd;
 }
 
 uint16_t hwCPUFrequency(void)
@@ -169,7 +172,18 @@ uint16_t hwCPUFrequency(void)
 
 int8_t hwCPUTemperature(void)
 {
-	return -127; // not implemented yet
+	adc_reg_map *regs = ADC1->regs;
+	regs->CR2 |= ADC_CR2_TSVREFE; // enable VREFINT and Temperature sensor
+	regs->SMPR1 |= ADC_SMPR1_SMP16 | ADC_SMPR1_SMP17;
+	adc_calibrate(ADC1);
+
+	//const uint16_t adc_temp = adc_read(ADC1, 16);
+	//const uint16_t vref = 1200 * 4096 / adc_read(ADC1, 17);
+	// calibrated at 25°C, ADC output = 1430mV, avg slope = 4.3mV / °C, increasing temp ~ lower voltage
+	const int8_t temp = static_cast<int8_t>((1430.0 - (adc_read(ADC1, 16) * 1200 / adc_read(ADC1,
+	                                        17))) / 4.3 + 25.0);
+	regs->CR2 &= ~ADC_CR2_TSVREFE; // disable VREFINT and temp sensor
+	return (temp - MY_STM32F1_TEMPERATURE_OFFSET) / MY_STM32F1_TEMPERATURE_GAIN;
 }
 
 uint16_t hwFreeMem(void)