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DSP28377D的ADC采样后结果寄存器值波动很大

如图里面所示,无论我是在ID端口输入恒定电压,还是直接在A0端口输入,结果寄存器ADCRESULT0的数一直都在波动,波动值大概有100左右,偶尔还会发生突变,变成接近0或者4095,我用的是12位AD模式,用16位的话波动值更大,用示波器检测电源信号,看到电源只有几毫伏的波动,所以一直不知道是哪出问题了,下面是AD的配置程序,还望各位答疑解惑

void ConfigureADC(void)
{
        EALLOW;

        //write configurations
        AdcaRegs.ADCCTL2.bit.PRESCALE = 6; //set ADCCLK divider to /4
        AdcbRegs.ADCCTL2.bit.PRESCALE = 6; //set ADCCLK divider to /4
    AdcSetMode(ADC_ADCA, ADC_RESOLUTION_12BIT, ADC_SIGNALMODE_SINGLE);
    AdcSetMode(ADC_ADCB, ADC_RESOLUTION_12BIT, ADC_SIGNALMODE_SINGLE);

        //Set pulse positions to late
        AdcaRegs.ADCCTL1.bit.INTPULSEPOS = 1;
        AdcbRegs.ADCCTL1.bit.INTPULSEPOS = 1;

        //power up the ADCs
        AdcaRegs.ADCCTL1.bit.ADCPWDNZ = 1;
        AdcbRegs.ADCCTL1.bit.ADCPWDNZ = 1;

        //delay for 1ms to allow ADC time to power up
        DELAY_US(1000);

        EDIS;
}


void SetupADC(void)
{
        Uint16 acqps;

        //determine minimum acquisition window (in SYSCLKS) based on resolution
        IF(ADC_RESOLUTION_12BIT == AdcaRegs.ADCCTL2.bit.RESOLUTION){
                acqps = 14; //75ns
        }
        else { //resolution is 16-bit
                acqps = 63; //320ns
        }

//Select the channels to convert and end of conversion flag
    //ADCA
    EALLOW;
    AdcaRegs.ADCSOC0CTL.bit.CHSEL = 0;  //SOC0 will convert pin A0
    AdcaRegs.ADCSOC0CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC0CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcaRegs.ADCSOC1CTL.bit.CHSEL = 1;  //SOC1 will convert pin A1
    AdcaRegs.ADCSOC1CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC1CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcaRegs.ADCSOC2CTL.bit.CHSEL = 2;  //SOC1 will convert pin A1
    AdcaRegs.ADCSOC2CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC2CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcaRegs.ADCSOC3CTL.bit.CHSEL = 3;  //SOC1 will convert pin A1
    AdcaRegs.ADCSOC3CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC3CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcaRegs.ADCSOC4CTL.bit.CHSEL = 4;  //SOC1 will convert pin A1
    AdcaRegs.ADCSOC4CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC4CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcaRegs.ADCSOC5CTL.bit.CHSEL = 5;  //SOC1 will convert pin A1
    AdcaRegs.ADCSOC5CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC5CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断

    //ADCB
    AdcbRegs.ADCSOC0CTL.bit.CHSEL = 0;  //SOC0 will convert pin B0
    AdcbRegs.ADCSOC0CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcbRegs.ADCSOC0CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcbRegs.ADCSOC1CTL.bit.CHSEL = 1;  //SOC1 will convert pin B1
    AdcbRegs.ADCSOC1CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcbRegs.ADCSOC1CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcbRegs.ADCSOC2CTL.bit.CHSEL = 2;  //SOC1 will convert pin B1
    AdcbRegs.ADCSOC2CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcbRegs.ADCSOC2CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
    AdcbRegs.ADCSOC3CTL.bit.CHSEL = 3;  //SOC1 will convert pin B1
    AdcbRegs.ADCSOC3CTL.bit.ACQPS = acqps; //sample window is acqps + 1 SYSCLK cycles
    AdcaRegs.ADCSOC3CTL.bit.TRIGSEL = 1; //这里设置1为timer0中断,设置0为软件中断
}


void AdcSetMode(Uint16 adc, Uint16 resolution, Uint16 signalmode)
{
        Uint16 adcOffsetTrimOTPIndex; //index into OTP table of ADC offset trims
        Uint16 adcOffsetTrim; //temporary ADC offset trim
        
        //re-populate INL trim
        CalAdcINL(adc);
        
        if(0xFFFF != *((Uint16*)GetAdcOffsetTrimOTP)){
                //offset trim function is programmed into OTP, so call it

                //calculate the index into OTP table of offset trims and call
                //function to return the correct offset trim
                adcOffsetTrimOTPIndex = 4*adc + 2*resolution + 1*signalmode;
                adcOffsetTrim = (*GetAdcOffsetTrimOTP)(adcOffsetTrimOTPIndex);
        }
        else {
                //offset trim function is not populated, so set offset trim to 0
                adcOffsetTrim = 0;
        }

        //Apply the resolution and signalmode to the specified ADC.
        //Also apply the offset trim and, if needed, linearity trim correction.
        switch(adc){
                case ADC_ADCA:
                        AdcaRegs.ADCCTL2.bit.RESOLUTION = resolution;
                        AdcaRegs.ADCCTL2.bit.SIGNALMODE = signalmode;
                        AdcaRegs.ADCOFFTRIM.all = adcOffsetTrim;
                        if(ADC_RESOLUTION_12BIT == resolution){

                                //12-bit linearity trim workaround
                                AdcaRegs.ADCINLTRIM1 &= 0xFFFF0000;
                                AdcaRegs.ADCINLTRIM2 &= 0xFFFF0000;
                                AdcaRegs.ADCINLTRIM4 &= 0xFFFF0000;
                                AdcaRegs.ADCINLTRIM5 &= 0xFFFF0000;
                        }
                break;
                case ADC_ADCB:
                        AdcbRegs.ADCCTL2.bit.RESOLUTION = resolution;
                        AdcbRegs.ADCCTL2.bit.SIGNALMODE = signalmode;
                        AdcbRegs.ADCOFFTRIM.all = adcOffsetTrim;
                        if(ADC_RESOLUTION_12BIT == resolution){

                                //12-bit linearity trim workaround
                                AdcbRegs.ADCINLTRIM1 &= 0xFFFF0000;
                                AdcbRegs.ADCINLTRIM2 &= 0xFFFF0000;
                                AdcbRegs.ADCINLTRIM4 &= 0xFFFF0000;
                                AdcbRegs.ADCINLTRIM5 &= 0xFFFF0000;
                        }
                break;
                case ADC_ADCC:
                        AdccRegs.ADCCTL2.bit.RESOLUTION = resolution;
                        AdccRegs.ADCCTL2.bit.SIGNALMODE = signalmode;
                        AdccRegs.ADCOFFTRIM.all = adcOffsetTrim;
                        if(ADC_RESOLUTION_12BIT == resolution){

                                //12-bit linearity trim workaround
                                AdccRegs.ADCINLTRIM1 &= 0xFFFF0000;
                                AdccRegs.ADCINLTRIM2 &= 0xFFFF0000;
                                AdccRegs.ADCINLTRIM4 &= 0xFFFF0000;
                                AdccRegs.ADCINLTRIM5 &= 0xFFFF0000;
                        }
                break;
                case ADC_ADCD:
                        AdcdRegs.ADCCTL2.bit.RESOLUTION = resolution;
                        AdcdRegs.ADCCTL2.bit.SIGNALMODE = signalmode;
                        AdcdRegs.ADCOFFTRIM.all = adcOffsetTrim;
                        if(ADC_RESOLUTION_12BIT == resolution){

                                //12-bit linearity trim workaround
                                AdcdRegs.ADCINLTRIM1 &= 0xFFFF0000;
                                AdcdRegs.ADCINLTRIM2 &= 0xFFFF0000;
                                AdcdRegs.ADCINLTRIM4 &= 0xFFFF0000;
                                AdcdRegs.ADCINLTRIM5 &= 0xFFFF0000;
                        }
                break;
        }
}

/* 
* Loads INL trim values from OTP into the trim registers of the specified ADC.
* Use only as part of AdcSetMode function, since linearity trim correction
* is needed for some modes.
*/
void CalAdcINL(Uint16 adc)
{
        switch(adc){
                case ADC_ADCA:
                        if(0xFFFF != *((Uint16*)CalAdcaINL)){
                                //trim function is programmed into OTP, so call it
                                (*CalAdcaINL)();
                        }
                        else {
                                //do nothing, no INL trim function populated
                        }
                        break;
                case ADC_ADCB:
                        if(0xFFFF != *((Uint16*)CalAdcbINL)){
                                //trim function is programmed into OTP, so call it
                                (*CalAdcbINL)();
                        }
                        else {
                                //do nothing, no INL trim function populated
                        }
                        break;
                case ADC_ADCC:
                        if(0xFFFF != *((Uint16*)CalAdccINL)){
                                //trim function is programmed into OTP, so call it
                                (*CalAdccINL)();
                        }
                        else {
                                //do nothing, no INL trim function populated
                        }
                        break;
                case ADC_ADCD:
                        if(0xFFFF != *((Uint16*)CalAdcdINL)){
                                //trim function is programmed into OTP, so call it
                                (*CalAdcdINL)();
                        }
                        else {
                                //do nothing, no INL trim function populated
                        }
                        break;
        }
}