sd24_ex6_singleConversionSingleConversionTempSensor.c

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//******************************************************************************
//  MSP430i20xx SD24 Example 06 - SD24, Using the Integrated Temperature Sensor
//
//  Description: This program uses the SD24 module to perform a single
//  conversion on a single channel which is internally connected to the SD24's
//  temperature sensor. Once the conversion is completed, the result is stored in
//  a variable then converted into Celsius and Fahrenheit values.
//
//  Test by setting a breakpoint at the indicated line. Upon reaching the breakpoint
//  the conversion result will be stored in the results array. The result will
//  then be taken and converted into degrees K, C, and F and be saved in the same
//  array.
//
//  ACLK = 32kHz, MCLK = SMCLK = Calibrated DCO = 16.384MHz, SD_CLK = 1.024MHz
//  * Ensure low_level_init.c is included when building/running this example *
//
//  Notes: For minimum Vcc required for SD24 module - see datasheet
//         100nF cap btw Vref and AVss is recommended when using 1.2V ref
//
//  Sensor's temperature coefficient is 2.158mV/K (from datasheet)
//  Sensor's offset voltage ranges from -100mv to 100mV (assume 0)
//  Vsensor = 1.32mV * DegK + Vsensor_offset (assuming 0mv for offset)
//  Vsensor = (SD24MEM0)/32767 * Vref(mV)
//  DegK = (SD24MEM0 * 1200)/32767/2.158 = (SD24MEM0 * 1200)/70711
//  DegC =  DegK - 273
//  DegF = (DegC * 9/5) + 32
//
//
//               MSP430i20xx
//             -----------------
//         /|\|                |
//          | |                |
//          --|RST             |
//            |                |        (A0.6+/- connected internally)
//            |A0.6+      VREF |---+    (to SD24's temperature sensor)
//            |A0.6-           |   |
//            |                |  -+- 100nF
//            |                |  -+-
//            |                |   |
//            |           AVss |---+
//
//  T. Witt
//  Yang Lu
//  Texas Instruments, Inc
//  June 2014
//  Built with Code Composer Studio v5.5
//******************************************************************************
#include "driverlib.h"
 
uint16_t results[4];                       // SD24 Conversion and Temp Results
                                                // results[0] = raw SD24 results
                                                // results[1] = temp in K
                                                // results[2] = temp in C
                                                // results[3] = temp in F
 
void main(void) {
    // Stop WDT
    WDT_hold(WDT_BASE);
 
    // Internal ref
    SD24_init(SD24_BASE, SD24_REF_INTERNAL);
 
    //Ch0 single mode, internal temp sensor
    SD24_initConverterAdvancedParam param = {0};
    param.converter = SD24_CONVERTER_0;
    param.conversionMode = SD24_SINGLE_MODE;
    param.groupEnable = SD24_NOT_GROUPED;
    param.inputChannel = SD24_INPUT_CH_TEMPERATURE;
    param.dataFormat = SD24_DATA_FORMAT_2COMPLEMENT;
    param.interruptDelay = SD24_FOURTH_SAMPLE_INTERRUPT;
    param.oversampleRatio = SD24_OVERSAMPLE_256;
    param.gain = SD24_GAIN_1;
    SD24_initConverterAdvanced(SD24_BASE, &param);
    SD24_enableInterrupt(SD24_BASE, SD24_CONVERTER_0, SD24_CONVERTER_INTERRUPT);
 
    // Delay ~200us for 1.2V ref to settle
    __delay_cycles(3200);
 
    while(1) {
        // Start conversion
        SD24_startConverterConversion(SD24_BASE, SD24_CONVERTER_0);
        // Enter LPM0 w/ interrupts
        __bis_SR_register(LPM0_bits | GIE); 
        // For debugger    
        __no_operation();
 
        // Calculate Temperatures in different scales
        results[1] = ((unsigned long)results[0] * 1200)/70711;
        results[2] = results[1] - 273;
        results[3] = (results[2] * 9/5) + 32;
 
        __no_operation();                       // SET BREAKPOINT HERE
    }
}
 
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=SD24_VECTOR
__interrupt void SD24_ISR(void) {
#elif defined(__GNUC__)
void __attribute__ ((interrupt(SD24_VECTOR))) SD24_ISR (void) {
#else
#error Compiler not supported!
#endif
    switch (__even_in_range(SD24IV,SD24IV_SD24MEM3)) {
        case SD24IV_NONE: break;
        case SD24IV_SD24OVIFG: break;
        case SD24IV_SD24MEM0:
                   // Save CH0 results (clears IFG)
                   results[0] = SD24_getHighWordResults(SD24_BASE, SD24_CONVERTER_0);
                   break;
        case SD24IV_SD24MEM1: break;
        case SD24IV_SD24MEM2: break;
        case SD24IV_SD24MEM3: break;
        default: break;
    }
    __bic_SR_register_on_exit(LPM0_bits);       // Wake up from LPM0
}