Hi,
I have a trouble with the internal temperature sensor. The code is the example included in the driverLib:
// MSP430FR69xx Demo - ADC12_B, Sample A10 Temp and Convert to oC and oF
//
// Description: A single sample is made on A10 with internal reference voltage
// 1.2V. Software manually sets ADC12SC to start sample and conversion and
// automatically cleared at EOC. It uses ADC12OSC to convert the sameple.
// The Mainloop sleeps the MSP430 in LPM4 to save power until ADC conversion
// is completed. ADC12_ISR forces exit from LPMx in on exit from interrupt
// handler so that the mainloop can execute and calculate oC and oF.
// ACLK = n/a, MCLK = SMCLK = default DCO ~ 1.045MHz, ADC12CLK = ADC12OSC
//
// Un-calibrated temperature measured from device to device will vary due to
// slope and offset variance from device to device - please see datasheet.
// Note: This example uses the TLV calibrated temperature to calculate
// the temperature
// (the TLV CALIBRATED DATA IS STORED IN THE INFORMATION SEGMENT, SEE DEVICE DATASHEET)
//
// MSP430FR6989
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// | |
// |A10 |
//
// William Goh
// Texas Instruments Inc.
// April 2014
// Built with IAR Embedded Workbench V5.60 & Code Composer Studio V6.0
//******************************************************************************
#include <msp430.h>
#define CALADC12_12V_30C *((unsigned int *)0x1A1A) // Temperature Sensor Calibration-30 C
//See device datasheet for TLV table memory mapping
#define CALADC12_12V_85C *((unsigned int *)0x1A1C) // Temperature Sensor Calibration-85 C
unsigned int temp;
volatile float temperatureDegC;
volatile float temperatureDegF;
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
// Initialize the shared reference module
// By default, REFMSTR=1 => REFCTL is used to configure the internal reference
while(REFCTL0 & REFGENBUSY); // If ref generator busy, WAIT
REFCTL0 |= REFVSEL_0 + REFON; // Enable internal 1.2V reference
/* Initialize ADC12_A */
ADC12CTL0 &= ~ADC12ENC; // Disable ADC12
ADC12CTL0 = ADC12SHT0_8 + ADC12ON; // Set sample time
ADC12CTL1 = ADC12SHP; // Enable sample timer
ADC12CTL3 = ADC12TCMAP; // Enable internal temperature sensor
ADC12MCTL0 = ADC12VRSEL_1 + ADC12INCH_30; // ADC input ch A30 => temp sense
ADC12IER0 = 0x001; // ADC_IFG upon conv result-ADCMEMO
while(!(REFCTL0 & REFGENRDY)); // Wait for reference generator
// to settle
ADC12CTL0 |= ADC12ENC;
while(1)
{
ADC12CTL0 |= ADC12SC; // Sampling and conversion start
__bis_SR_register(LPM0_bits + GIE); // LPM4 with interrupts enabled
__no_operation();
// Temperature in Celsius. See the Device Descriptor Table section in the
// System Resets, Interrupts, and Operating Modes, System Control Module
// chapter in the device user's guide for background information on the
// used formula.
temperatureDegC = (float)(((long)temp - CALADC12_12V_30C) * (85 - 30)) /
(CALADC12_12V_85C - CALADC12_12V_30C) + 30.0f;
// Temperature in Fahrenheit Tf = (9/5)*Tc + 32
temperatureDegF = temperatureDegC * 9.0f / 5.0f + 32.0f;
__no_operation(); // SET BREAKPOINT HERE
}
}
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC12_VECTOR))) ADC12ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(ADC12IV, ADC12IV_ADC12RDYIFG))
{
case ADC12IV_NONE: break; // Vector 0: No interrupt
case ADC12IV_ADC12OVIFG: break; // Vector 2: ADC12MEMx Overflow
case ADC12IV_ADC12TOVIFG: break; // Vector 4: Conversion time overflow
case ADC12IV_ADC12HIIFG: break; // Vector 6: ADC12BHI
case ADC12IV_ADC12LOIFG: break; // Vector 8: ADC12BLO
case ADC12IV_ADC12INIFG: break; // Vector 10: ADC12BIN
case ADC12IV_ADC12IFG0: // Vector 12: ADC12MEM0 Interrupt
temp = ADC12MEM0; // Move results, IFG is cleared
__bic_SR_register_on_exit(LPM4_bits); // Exit active CPU
break;
case ADC12IV_ADC12IFG1: break; // Vector 14: ADC12MEM1
case ADC12IV_ADC12IFG2: break; // Vector 16: ADC12MEM2
case ADC12IV_ADC12IFG3: break; // Vector 18: ADC12MEM3
case ADC12IV_ADC12IFG4: break; // Vector 20: ADC12MEM4
case ADC12IV_ADC12IFG5: break; // Vector 22: ADC12MEM5
case ADC12IV_ADC12IFG6: break; // Vector 24: ADC12MEM6
case ADC12IV_ADC12IFG7: break; // Vector 26: ADC12MEM7
case ADC12IV_ADC12IFG8: break; // Vector 28: ADC12MEM8
case ADC12IV_ADC12IFG9: break; // Vector 30: ADC12MEM9
case ADC12IV_ADC12IFG10: break; // Vector 32: ADC12MEM10
case ADC12IV_ADC12IFG11: break; // Vector 34: ADC12MEM11
case ADC12IV_ADC12IFG12: break; // Vector 36: ADC12MEM12
case ADC12IV_ADC12IFG13: break; // Vector 38: ADC12MEM13
case ADC12IV_ADC12IFG14: break; // Vector 40: ADC12MEM14
case ADC12IV_ADC12IFG15: break; // Vector 42: ADC12MEM15
case ADC12IV_ADC12IFG16: break; // Vector 44: ADC12MEM16
case ADC12IV_ADC12IFG17: break; // Vector 46: ADC12MEM17
case ADC12IV_ADC12IFG18: break; // Vector 48: ADC12MEM18
case ADC12IV_ADC12IFG19: break; // Vector 50: ADC12MEM19
case ADC12IV_ADC12IFG20: break; // Vector 52: ADC12MEM20
case ADC12IV_ADC12IFG21: break; // Vector 54: ADC12MEM21
case ADC12IV_ADC12IFG22: break; // Vector 56: ADC12MEM22
case ADC12IV_ADC12IFG23: break; // Vector 58: ADC12MEM23
case ADC12IV_ADC12IFG24: break; // Vector 60: ADC12MEM24
case ADC12IV_ADC12IFG25: break; // Vector 62: ADC12MEM25
case ADC12IV_ADC12IFG26: break; // Vector 64: ADC12MEM26
case ADC12IV_ADC12IFG27: break; // Vector 66: ADC12MEM27
case ADC12IV_ADC12IFG28: break; // Vector 68: ADC12MEM28
case ADC12IV_ADC12IFG29: break; // Vector 70: ADC12MEM29
case ADC12IV_ADC12IFG30: break; // Vector 72: ADC12MEM30
case ADC12IV_ADC12IFG31: break; // Vector 74: ADC12MEM31
case ADC12IV_ADC12RDYIFG: break; // Vector 76: ADC12RDY
default: break;
}
}
The reference is 1.2V and the temperature seems calibrated. In debug phase we check the variable VALUE and repeating the single acquisition, we observe that there is a variation in the temperature value up to 5C. Is this the accuracy of the sensor? In this case it seems very poor.
Or there are some code errors. Are there other examples (correct)?
Thank you
Warm regard.
