drivers/power_monitor: Implement temperature sensor support for INA228 / INA238

msg/BatteryStatus.msg

@@ -7,7 +7,7 @@ float32 discharged_mah		# Discharged amount in mAh, -1 if unknown
 float32 remaining				# From 1 to 0, -1 if unknown
 float32 scale					# Power scaling factor, >= 1, or -1 if unknown
 float32 time_remaining_s			# predicted time in seconds remaining until battery is empty under previous averaged load, NAN if unknown
-float32 temperature			# temperature of the battery. NaN if unknown
+float32 temperature				# Temperature of the battery in degrees Celcius, NaN if unknown
 uint8 cell_count				# Number of cells, 0 if unknown
 
 uint8 BATTERY_SOURCE_POWER_MODULE = 0

src/drivers/power_monitor/ina228/ina228.cpp

@@ -88,6 +88,7 @@ INA228::INA228(const I2CSPIDriverConfig &config, int battery_index) :
 	_battery.setConnected(false);
 	_battery.updateVoltage(0.f);
 	_battery.updateCurrent(0.f);
+	_battery.updateTemperature(0.f);
 	_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 }
 
@@ -306,6 +307,7 @@ INA228::collect()
 	// success = success && (read(INA228_REG_POWER, _power) == PX4_OK);
 	success = success && (read(INA228_REG_CURRENT, _current) == PX4_OK);
 	//success = success && (read(INA228_REG_VSHUNT, _shunt) == PX4_OK);
+	success = success && (read(INA228_REG_DIETEMP, _temperature) == PX4_OK);
 
 	if (!success) {
 		PX4_DEBUG("error reading from sensor");
@@ -315,6 +317,7 @@ INA228::collect()
 	_battery.setConnected(success);
 	_battery.updateVoltage(static_cast<float>(_bus_voltage * INA228_VSCALE));
 	_battery.updateCurrent(static_cast<float>(_current * _current_lsb));
+	_battery.updateTemperature(static_cast<float>(_temperature * INA228_TSCALE));
 	_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 
 	perf_end(_sample_perf);
@@ -381,6 +384,7 @@ INA228::RunImpl()
 		_battery.setConnected(false);
 		_battery.updateVoltage(0.f);
 		_battery.updateCurrent(0.f);
+		_battery.updateTemperature(0.f);
 		_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 
 		if (init() != PX4_OK) {

src/drivers/power_monitor/ina228/ina228.h

@@ -291,6 +291,7 @@ using namespace time_literals;
 #define INA228_CONST                         13107.2e6f  /* is an internal fixed value used to ensure scaling is maintained properly  */
 #define INA228_SHUNT                         0.0005f   /* Shunt is 500 uOhm */
 #define INA228_VSCALE                        1.95e-04f  /* LSB of voltage is 195.3125 uV/LSB */
+#define INA228_TSCALE                        7.8125e-03f /* LSB of temperature is 7.8125 mDegC/LSB */
 
 #define swap16(w)                            __builtin_bswap16((w))
 #define swap32(d)                            __builtin_bswap32((d))
@@ -339,6 +340,7 @@ private:
 	int32_t           _bus_voltage{0};
 	int64_t           _power{0};
 	int32_t           _current{0};
+	int16_t           _temperature{0};
 	int32_t           _shunt{0};
 	int16_t           _cal{0};
 	int16_t           _range{INA228_ADCRANGE_HIGH};

src/drivers/power_monitor/ina238/ina238.cpp

@@ -80,6 +80,7 @@ INA238::INA238(const I2CSPIDriverConfig &config, int battery_index) :
 	_battery.setConnected(false);
 	_battery.updateVoltage(0.f);
 	_battery.updateCurrent(0.f);
+	_battery.updateTemperature(0.f);
 	_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 }
 
@@ -224,9 +225,11 @@ int INA238::collect()
 	bool success{true};
 	int16_t bus_voltage{0};
 	int16_t current{0};
+	int16_t temperature{0};
 
 	success = (RegisterRead(Register::VS_BUS, (uint16_t &)bus_voltage) == PX4_OK);
 	success = success && (RegisterRead(Register::CURRENT, (uint16_t &)current) == PX4_OK);
+	success = success && (RegisterRead(Register::DIETEMP, (uint16_t &)temperature) == PX4_OK);
 
 	if (!success || hrt_elapsed_time(&_last_config_check_timestamp) > 100_ms) {
 		// check configuration registers periodically or immediately following any failure
@@ -250,6 +253,7 @@ int INA238::collect()
 	_battery.setConnected(success);
 	_battery.updateVoltage(static_cast<float>(bus_voltage * INA238_VSCALE));
 	_battery.updateCurrent(static_cast<float>(current * _current_lsb));
+	_battery.updateTemperature(static_cast<float>(temperature * INA238_TSCALE));
 	_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 
 	perf_end(_sample_perf);
@@ -309,6 +313,7 @@ void INA238::RunImpl()
 		_battery.setConnected(false);
 		_battery.updateVoltage(0.f);
 		_battery.updateCurrent(0.f);
+		_battery.updateTemperature(0.f);
 		_battery.updateAndPublishBatteryStatus(hrt_absolute_time());
 
 		if (init() != PX4_OK) {

src/drivers/power_monitor/ina238/ina238.h

@@ -73,6 +73,7 @@ using namespace ina238;
 #define INA238_DN_MAX                        32768.0f   /* 2^15 */
 #define INA238_CONST                         819.2e6f  /* is an internal fixed value used to ensure scaling is maintained properly  */
 #define INA238_VSCALE                        3.125e-03f  /* LSB of voltage is 3.1255 mV/LSB */
+#define INA238_TSCALE                        7.8125e-03f /* LSB of temperature is 7.8125 mDegC/LSB */
 
 #define DEFAULT_MAX_CURRENT                  327.68f    /* Amps */
 #define DEFAULT_SHUNT                        0.0003f   /* Shunt is 300 uOhm */

src/drivers/power_monitor/ina238/ina238_registers.hpp

@@ -14,6 +14,7 @@ enum class Register : uint8_t {
 	ADCCONFIG = 0x01, // ADC Configuration Register
 	SHUNT_CAL = 0x02, // Shunt Calibration Register
 	VS_BUS = 0x05,
+	DIETEMP = 0x06,
 	CURRENT = 0x07,
 	MANUFACTURER_ID = 0x3e,
 	DEVICE_ID = 0x3f

src/lib/battery/battery.cpp

@@ -106,6 +106,11 @@ void Battery::updateCurrent(const float current_a)
 	_current_a = current_a;
 }
 
+void Battery::updateTemperature(const float temperature_c)
+{
+	_temperature_c = temperature_c;
+}
+
 void Battery::updateBatteryStatus(const hrt_abstime &timestamp)
 {
 	// Require minimum voltage otherwise override connected status
@@ -149,7 +154,7 @@ battery_status_s Battery::getBatteryStatus()
 	battery_status.remaining = _state_of_charge;
 	battery_status.scale = _scale;
 	battery_status.time_remaining_s = computeRemainingTime(_current_a);
-	battery_status.temperature = NAN;
+	battery_status.temperature = _temperature_c;
 	battery_status.cell_count = _params.n_cells;
 	battery_status.connected = _connected;
 	battery_status.source = _source;

src/lib/battery/battery.h

@@ -91,6 +91,7 @@ public:
 	void setStateOfCharge(const float soc) { _state_of_charge = soc; _external_state_of_charge = true; }
 	void updateVoltage(const float voltage_v);
 	void updateCurrent(const float current_a);
+	void updateTemperature(const float temperature_c);
 
 	/**
 	 * Update state of charge calculations
@@ -168,6 +169,7 @@ private:
 	float _current_a{-1};
 	AlphaFilter<float>
 	_current_average_filter_a; ///< averaging filter for current. For FW, it is the current in level flight.
+	float _temperature_c{NAN};
 	float _discharged_mah{0.f};
 	float _discharged_mah_loop{0.f};
 	float _state_of_charge_volt_based{-1.f}; // [0,1]