154 lines
5.4 KiB
C
154 lines
5.4 KiB
C
//###########################################################################
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//
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// FILE: F2837xD_TempSensorConv.c
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//
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// TITLE: F2837xD Temperature Sensor Conversion Functions
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//
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//###########################################################################
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// $TI Release: F2837xD Support Library v3.05.00.00 $
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// $Release Date: Tue Jun 26 03:15:23 CDT 2018 $
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// $Copyright:
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// Copyright (C) 2013-2018 Texas Instruments Incorporated - http://www.ti.com/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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//
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// Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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//
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// Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the
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// distribution.
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//
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// Neither the name of Texas Instruments Incorporated nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// $
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//###########################################################################
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//
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// Included Files
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//
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#include "F2837xD_device.h"
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#include "F2837xD_Examples.h"
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//
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// Defines
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//
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#define FP_SCALE 32768 //Scale factor for Q15 fixed point numbers (2^15)
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#define FP_ROUND FP_SCALE/2 //Added to Q15 numbers before converting to
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//integer to round the number.
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#define KELVIN 273 // Amount to add to Q15 fixed point numbers
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// to shift from Celsius to Kelvin
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// (Converting guarantees number is
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// positive, which makes rounding more
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// efficient)
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#define KELVIN_OFF FP_SCALE*KELVIN
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#define getTempSlope() (*(int (*)(void))0x7036E)() //Slope of temperature sensor
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//(deg. C / ADC code).
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//Stored in fixed point Q15
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//format.
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#define getTempOffset() (*(int (*)(void))0x70372)() //ADC code corresponding to
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//temperature sensor output
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//at 0 deg. C
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//
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// Globals
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//
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float32 tempSensor_tempSlope;
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float32 tempSensor_tempOffset;
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float32 tempSensor_scaleFactor;
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//
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// InitTempSensor - Initialize the temperature sensor by powering up the
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// sensor, loading the calibration values from OTP to RAM,
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// and recording the intended VREFHI voltage.
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// Note: This function doesn't support VREFLO != 0.0V,
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// but this could be implemented if desired.
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//
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void InitTempSensor(float32 vrefhi_voltage)
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{
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EALLOW;
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//
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//power up the the temperature sensor
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//
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AnalogSubsysRegs.TSNSCTL.bit.ENABLE = 1;
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//
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//delay to allow the sensor to power up
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//
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DELAY_US(1000);
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EDIS;
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//
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//need to remember VREFHI voltage so that sensor readings can be scaled
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//to match 2.5V values used for calibration data.
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//
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tempSensor_scaleFactor = vrefhi_voltage;
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//
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//check the device revision
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//
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if(DevCfgRegs.REVID >= 3)
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{
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//
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//for production devices (Rev. C), pull the slope and offset from OTP
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//
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tempSensor_tempSlope = (int32)getTempSlope();
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tempSensor_tempOffset = getTempOffset();
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}
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else
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{
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//
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//for pre-production devices, use these static values for slope
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//and offset
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//
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tempSensor_tempSlope = 5196;
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tempSensor_tempOffset = 1788;
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}
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}
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//
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// GetTemperatureC - This function uses the reference data stored in OTP to
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// convert the raw temperature sensor reading into degrees C
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//
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int16 GetTemperatureC(int16 sensorSample)
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{
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sensorSample = (int16)((tempSensor_scaleFactor/2.5)*(sensorSample));
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return (((sensorSample - tempSensor_tempOffset)*tempSensor_tempSlope +
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FP_ROUND + KELVIN_OFF)/FP_SCALE - KELVIN);
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}
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//
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// GetTemperatureK - This function uses the reference data stored in OTP to
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// convert the raw temperature sensor reading into degrees K
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//
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int16 GetTemperatureK(int16 sensorSample)
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{
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sensorSample = (int16)((2.5/tempSensor_scaleFactor)*(sensorSample));
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return (((sensorSample - tempSensor_tempOffset)*tempSensor_tempSlope +
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FP_ROUND + KELVIN_OFF)/FP_SCALE);
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}
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//
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// End of file
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//
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