关于MSP430FR5949内部温度采样的问题，望解答

我用官方给的例子，测得的温度比较准确，官方AD基准选的1.2V，采样保持时间ADC12SHT0_8程序如下：

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//******************************************************************************
// MSP430FR59xx 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)
//
// MSP430FR5969
// —————–
// /|\| XIN|-
// | | |
// –|RST XOUT|-
// | |
// |A10 |
//
// William Goh
// Texas Instruments Inc.
// February 2014
// Built with IAR Embedded Workbench Version: 5.60 & Code Composer Studio V5.5
//******************************************************************************
#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;
}
}

我自己用的2.5V的基准，程序如下，不同的板子采样出来的温度值差别很大，有的为负值，这是怎么回事，程序如下：

STATIC VOID Bsp_InitAD(VOID)
{
/* 初始化AD引脚 *///P1.0，P1.1
P1SEL0 |= P1_ADI|P1_AC2;
P1SEL1 |= P1_ADI|P1_AC2; P3SEL0 |= P3_AC1|P3_BIT1|P3_BIT2;
P3SEL1 |= P3_AC1|P3_BIT1|P3_BIT2;
//
while(REFCTL0 & REFGENBUSY); // If ref generator busy, WAIT
REFCTL0 |= REFVSEL_3; //调高后影响采样精度
REFCTL0 |= REFON;
//REFCTL0 |= REFON;//10.30
ADC12CTL0 &=~ADC12ENC;

ADC12CTL1 = ADC12SHP\
|ADC12CONSEQ_1 \
|ADC12SHS_0\
|ADC12SSEL_0;

ADC12CTL2 = ADC12RES_2;
ADC12CTL3 = ADC12CSTARTADD_0|ADC12TCMAP;
//电流 A0 ADC12MCTL0 = ADC12VRSEL_1\
|ADC12INCH_0;
//电压AC2 A1
ADC12MCTL1 = ADC12VRSEL_1\
|ADC12INCH_1;
//电压AC1 A12
ADC12MCTL2 = ADC12VRSEL_1\
|ADC12INCH_12;
//基准1.25 A13
ADC12MCTL3 = ADC12VRSEL_1\
|ADC12INCH_13;
//电池 A14
ADC12MCTL4 = ADC12VRSEL_1\
|ADC12INCH_14;
//温度
ADC12MCTL5 = ADC12VRSEL_1\
|ADC12INCH_30\
|ADC12EOS;
ADC12CTL0 = ADC12ON\
|ADC12MSC\
|ADC12ENC\
|ADC12SHT0_3

}

#pragma vector = TIMER2_A1_VECTOR //2500US采样单周期采样8个点
__interrupt void Timer2_A1_ISR (void)
{
switch(__even_in_range(TA2IV, TA2IV_TAIFG))
{
case TA2IV_TAIFG:
ST_UINT16 Wp = g_Sys.AD.AdNum;

Wp = (Wp+10) & SYS_AD_DATA_SIZE;
ADC12CTL0 |=ADC12SC;
g_Sys.AD.CData[Wp] = ADC12MEM0;//电流
g_Sys.AD.DData[Wp] = ADC12MEM1;//电场
g_Sys.AD.TempPow = ADC12MEM4;//wendu
g_Sys.AD.TempT = ADC12MEM5;//wendu

g_Sys.AD.AdNum = Wp;
break;
}
}

温度计算程序：

temperatureDegC = (float)(((long)g_Sys.AD.TempT*2 – CALADC12_12V_30C) * (85 – 30)) /
(CALADC12_12V_85C – CALADC12_12V_30C) + 30.0f;

灰小子：

你的计算公式是有问题的。例程中基准电压1.2v，公式为：

temperatureDegC = (float)(((long)temp – CALADC12_12V_30C) * (85 – 30)) /(CALADC12_12V_85C – CALADC12_12V_30C) + 30.0f;

junpeng li：

回复 灰小子:

我选的基准为2.5V，所以我乘了2，实验发现AD的保持周期影响温度的AD值，基准调高后出来转换的电压确实不准确，如何解决，有2.5v基准的历程吗？

junpeng li：

回复 灰小子:

我选的基准为2.5V，所以我乘了2，实验发现AD的保持周期影响温度的AD值，基准调高后出来转换的电压确实不准确，如何解决，有2.5v基准的历程吗？

junpeng li：

回复 junpeng li:

不那么费劲了，我把温度改为可以校准的了

junpeng li：

回复 HG:

大神果然是大神，问题解决，不过AD采样的保持时间要设置为sh_8,这样采样出来的才准确。

junpeng li：

回复 HG:

Thankyou very much