LM50C series (LM50C, LM50-Q1)

LM50C series (LM50C, LM50-Q1) is a temperatures sensor IC (-40 °C to +125 °C) made by Texas Instruments. This posting will provide the OSS-ECAL(Open Source Software for Electronic Components Abstraction Layer) for LM50C and LM50-Q1.
MCU interface : ADC

CAUTION:Please be sure to refer to the latest version of the Datasheet prior to actual design.

LM50C series (LM50C, LM50-Q1)

General description

The LM50 and LM50-Q1 devices are precision integrated-circuit temperature sensors that can sense a –40°C to 125°C temperature range using a single positive supply. The output voltage of the device is linearly proportional to temperature (10 mV/°C) and has a DC offset of 500 mV. The offset allows reading negative temperatures without the need for a negative supply.

The ideal output voltage of the LM50 or LM50-Q1 ranges from 100 mV to 1.75 V for a –40°C to 125°C temperature range. The LM50 and LM50-Q1 do not require any external calibration or trimming to provide accuracies of ±3°C at room temperature and ±4°C over the full –40°C to 125°C temperature range. Trimming and calibration of the LM50 and LM50-Q1 at the wafer level assure low cost and high accuracy. The linear output, 500 mV offset, and factory calibration of the LM50 and LM50-Q1 simplify the circuitry requirements in a single supply environment where reading negative temperatures is necessary. Because the quiescent current of the LM50 and LM50-Q1 is less than 130 µA, self-heating is limited to a very low 0.2°C in still air.

Feature

LM50-Q1 is AEC-Q100 Grade 1 Qualified and is Manufactured on an Automotive Grade Flow
Calibrated Directly in Degrees Celsius (Centigrade)
Linear + 10 mV/°C Scale Factor
±2°C Accuracy Specified at 25°C
Specified for Full –40° to 125°C Range
Suitable for Remote Applications
Low Cost Due to Wafer-Level Trimming
Operates From 4.5 V to 10 V
Less Than 130-µA Current Drain
Low Self-Heating: Less Than 0.2°C in Still A
Nonlinearity Less Than 0.8°C Over Temp
UL Recognized Component

Application

Automotive
Computers
Disk Drives
Battery Management
FAX Machines
Printers
Portable Medical Instruments
HVAC
Power Supply Modules

OSS-ECAL specification

API Function

etSTS oLM50C( etCMD cmd, float32* rlt )

The oLM50C function is an API function that executes LM50C series (LM50C, LM50-Q1) processing according to the command in the argument.

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_MIN	Minimum temperature error (rlt is minimum temperature)
		eSTS_ERR_MAX	Maximum temperature error (rlt is maximum temperature)
		eSTS_ERR_HAL_ADC	HAL ADC Error
		eSTS_ERR_COMMAND_CODE	Command selection error
		eSTS_ERR_OTHERS_RUN	Other components are executing the process
		eSTS_ERR_HAL_OTHERS_RUN	Other application is running HAL
		eSTS_ERR_ADC_OBJECT	AD conversion object selection error
Parameter IN	etCMD cmd	OSS-ECAL command code
		eCMD_START	Command to start AD conversion.
		eCMD_READ	Command that reads the AD conversion value, converts the AD conversion value to a characteristic Temperature, and stores the Temperature in rlt. AD conversion value to temperature conversion equation Voltage value = (AD conversion value × VDD) / ( 2^{AD bit} ) Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)
		eCMD_START_READ	Command that starts AD conversion, waits for AD conversion to finish, reads out the AD conversion value, converts the AD conversion value to a characteristic Temperature, and stores the Temperature in rlt. AD conversion value to temperature conversion equation Voltage value = (AD conversion value × VDD) / ( 2^{AD bit} ) Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)
Parameter OUT	float32* rlt	Temperature -40 to 125 [°C]

Command Correspondence Table by HAL

Arduino	eCMD_START_READ
ARM Mbed	eCMD_START_READ
AUTOSAR	–
Infineon ModusToolbox	eCMD_START_READ
NXP MCUXpresso iMXRT1051B_1052B	eCMD_START eCMD_READ eCMD_START_READ
Renesas SSP	eCMD_START eCMD_READ eCMD_START_READ
STM STM32Cube FW_F4	eCMD_START eCMD_READ eCMD_START_READ

etSTS oLM50C_START(void)

The oLM50C_START function is an API function to start AD conversion of the LM50C series (LM50C, LM50-Q1).

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_HAL_ADC	HAL ADC Error
		eSTS_ERR_OTHERS_RUN	Other components are executing the process
		eSTS_ERR_HAL_OTHERS_RUN	Other application is running HAL
		eSTS_ERR_ADC_OBJECT	AD conversion object selection error

Function Correspondence Table by HAL

Arduino	–
ARM Mbed	–
AUTOSAR	X
Infineon ModusToolbox	–
NXP MCUXpresso iMXRT1051B_1052B	X
Renesas SSP	X
STM STM32Cube FW_F4	X

etSTS oLM50C_READ( float32* rlt )

The oLM50C_READ function is an API function that checks for the end of AD conversion of the LM50C series (LM50C, LM50-Q1), reads the AD conversion value, converts the AD conversion value to a characteristic temperature, and stores the temperature in rlt.

AD conversion value to temperature conversion equation
Voltage value = (AD conversion value × VDD) / ( 2^{AD bit} )
Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_MIN	Minimum temperature error (rlt is minimum temperature)
		eSTS_ERR_MAX	Maximum temperature error (rlt is maximum temperature)
		eSTS_ERR_HAL_ADC	HAL ADC Error
		eSTS_ERR_TIMEOUT	ADC Timeout error (AUTOSAR only)
		eSTS_ERR_OTHERS_RUN	Other components are executing the process
		eSTS_ERR_ADC_OBJECT	AD conversion object selection error
Parameter OUT	float32* rlt	Temperature -40 to 125 [°C]

Function Correspondence Table by HAL

Arduino	–
ARM Mbed	–
AUTOSAR	X	Time-out time ADC_TIMEOUT [us] setting
Infineon ModusToolbox	–
NXP MCUXpresso iMXRT1051B_1052B	X
Renesas SSP	X
STM STM32Cube FW_F4	X	Time-out time HAL_MAX_DELAY

etSTS oLM50C_START_READ( float32* rlt )

The oLM50C_START_READ function is an API function that starts an AD conversion of the LM50C series (LM50C, LM50-Q1), waits for the AD conversion to finish, reads the AD conversion value, converts the AD conversion value to a temperature characteristic, and stores the temperature in rlt.

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_MIN	Minimum temperature error (rlt is minimum temperature)
		eSTS_ERR_MAX	Maximum temperature error (rlt is maximum temperature)
		eSTS_ERR_HAL_ADC	HAL ADC Error
		eSTS_ERR_OTHERS_RUN	Other components are executing the process
		eSTS_ERR_HAL_OTHERS_RUN	Other application is running HAL
		eSTS_ERR_ADC_OBJECT	AD conversion object selection error
Parameter OUT	float32* rlt	Temperature -40 to 125 [°C]

Function Correspondence Table by HAL

Arduino	X
ARM Mbed	X
AUTOSAR	–
Infineon ModusToolbox	X
NXP MCUXpresso iMXRT1051B_1052B	X
Renesas SSP	X
STM STM32Cube FW_F4	X	Time-out time HAL_MAX_DELAY

API functions for AUTOSAR

In AUTOSAR, the ADC group and channels of the MCU may be registered to the MCAL ADC channel group for AD conversion. In such a case, use the following API functions.

etSTS oMCAL_ADC_GR_START( Adc_GroupType gr )

The oMCAL_ADC_GR_START function is an API function that initiates conversion of a ADC channel group.

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_HAL_BUSY	HAL running
Parameter IN	Adc_GroupType gr	ID value of ADC channel group

etSTS oMCAL_ADC_GR_READ( Adc_GroupType gr, Adc_ValueGroupType* buf )

The oMCAL_ADC_GR_READ function is an API function that checks the end of ADC conversion for the ADC channel group, reads each AD conversion value, and stores each AD conversion value in buf. This function has a Timeout function and should be used with the ADC_TIMEOUT value set.

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_HAL_ADC	HAL ADC Error
		eSTS_ERR_TIMEOUT	ADC Timeout error (AUTOSAR only)
		sSTS_ERR_PROCESS	The return value of the Adc_GetGroupStatus function is other than the following value. ADC_STREAM_COMPLETED ADC_BUSY
Parameter IN	Adc_GroupType gr	ID value of ADC channel group
Parameter OUT	Adc_ValueGroupType* buf	First address of buffer of ADC channel group

etSTS oPRC_CHAR_CONV_L_FF( sint32 before, const stCOEF_L_FF coef, float32* rlt )

The oPRC_CHAR_CONV_L_FF function is a common process function. This function converts the value of the argument before (AD conversion value) to a voltage, converts the voltage linearly by the constant coef, and limits the converted value by the maximum minimum value.

Return value	etSTS	OSS-ECAL status code
		eSTS_FIN	Completed successfully
		eSTS_ERR_MIN	Minimum temperature error (rlt is minimum temperature)
		eSTS_ERR_MAX	Maximum temperature error (rlt is maximum temperature)
Parameter OUT	float32* rlt	Temperature -40 to 125 [°C]

Sample program

etSTS oss_ecal( void )
{
        /*********************************************************************/
        /* ADC Gr is registered with multiple Ch and AD conversion is        */
        /* performed to convert LM50C temperature.                           */
        /*********************************************************************/
        Adc_ValueGroupType val = 0;
        sint32 wk = 0;
        float32 phy = 0.0F;
        
        /* ADC Gr(Multi-Ch) start */
        sts = oMCAL_ADC_GR_START( ADC_LM50C_GR );
        if( sts == eSTS_FIN )
        {
                /* ADC Gr(Multi-Ch) value read */
                sts = oMCAL_ADC_GR_READ( ADC_LM50C_GR, GR_BUF );
                if( sts == eSTS_FIN )
                {
                        /* LM50C Temperature conversion */
                        /* Get A/D value */
                        val = *(GR_BUF+ADC_LM50C_CH);
                        /* Linear characteristic conversion */
                        wk = (sint32)mac_max_u16( val );
                        sts = oPRC_CHAR_CONV_L_FF( wk, cCOEF_LM50C, &phy );
                        if( sts == eSTS_FIN )
                        {
                                vgPHY = phy;
                        }
                        else
                        {
                                /* nothing to do */
                        }
                }
                else
                {
                        /* nothing to do */
                }
        }
        else
        {
                /* nothing to do */
        }
}

Files

Folder^*	File	Summary
LM50C_HALNAME_VERSION/sample	sample.c (.cpp)	Sample Application Program
	sample.h	Sample Application Header
LM50C_HALNAME_VERSION	oLM50C.c (.cpp)	OSS-ECAL Program for LM50C series (LM50C, LM50-Q1)
	oLM50C.h	OSS-ECAL Header for LM50C series (LM50C, LM50-Q1)
	LM50C_ARDUINO.ino	Sample application programs for Arduino
	oss_ecal.h	OSS-ECAL Common Header (Ver 01.00.00 or later, AUTOSAR is Ver 01.01.07 or later)
	oTypes.h	Typedef header file for AUTOSAR
	user_setting.c (.cpp)	Const and Table of User setting
	user_setting.h	Header of User setting
	readme.md	Readme
	OSS-ECAL Terms of Use.txt	OSS-ECAL Terms of Use

* For HALNAME, please refer to HAL Support.

HAL Support List

HAL	MCU*	Development environment*	HALNAME
Arduino 1.8.6	ATmega2560 ATmega328P	Mega 2560 Rev3 Arduino Pro Mini 3.3V	ARDUINO
ARM Mbed 6.17.0	STM32F401RE	STM32 Nucleo-64 boards	MBED
AUTOSAR 4.4 (MCAL)	S32K144	S32K144EVB-Q100	MCAL
Infineon ModusToolbox HAL Cat1 2.4.3	CYBLE-416045-02	CY8CPROTO-063-BLE PSoC 6 BLE Prototyping Kit	ModusToolbox
NXP MCUXpresso SDK iMXRT1051B_1052B ksdk2_0	MIMXRT1052DVL6A	IMXRT1050-EVKB	iMXRT1051B1052B
Renesas SSP 2.4.0	R7FS7G27H3A01CFC	S7G2 SK	SSP
STM STM32Cube FW_F4 V1.27.1	STM32F401RE	STM32 Nucleo-64 boards	STM32F4

* MCU and development environment at the time of development. Even if the same HAL is used, different MCUs and development environments may not work together.

OSS-ECAL Download

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Built-in How to

How to incorporate OSS-ECAL into user programs

How to incorporate multiple OSS-ECALs in a user program (same MCU function)

How to incorporate multiple OSS-ECALs in a user program (different MCU function)

How to incorporate multiple identical electronic components into a user program

How to reduce the impact on user programs by replacing electronic components

CAUTION

The sample version of OSS-ECAL is not intended to be used with Threads (Tasks) or interrupts of different priority. Please do not use it as in the example below.

Example: If each sensor is assigned to the same ADC group and the OSS-ECAL API is executed in processes with different priorities, correct values may not be obtained.
ADC Gr0 Ch0　Temperature sensor AD22100A　100ms cycle Thread (low priority) to take in temperature
ADC Gr0 Ch1　Pressure sensor　　 MPX5999D　Event interrupts (high priority) to take pressure