关于28377d 16位AD采样问题-TI中文支持网

我想使用定时器中断触发16位AD采样，一次触发对三相电压、三相电路分别进行采样转换，我的配置如下：

void ConfigureADC(void)
{
EALLOW;

//write configurations
AdcaRegs.ADCCTL2.bit.PRESCALE = 6; // set ADCCLK divider to /4 ADCCLK = Input Clock / x
AdcbRegs.ADCCTL2.bit.PRESCALE = 6; // set ADCCLK divider to /4 AD转换时钟
AdccRegs.ADCCTL2.bit.PRESCALE = 6; // set ADCCLK divider to /4
AdcdRegs.ADCCTL2.bit.PRESCALE = 6; // set ADCCLK divider to /4

AdcSetMode(ADC_ADCA, ADC_RESOLUTION_16BIT, ADC_SIGNALMODE_DIFFERENTIAL);
AdcSetMode(ADC_ADCB, ADC_RESOLUTION_16BIT, ADC_SIGNALMODE_DIFFERENTIAL);
// AdcSetMode(ADC_ADCC, ADC_RESOLUTION_16BIT, ADC_SIGNALMODE_DIFFERENTIAL);
AdcSetMode(ADC_ADCD, ADC_RESOLUTION_16BIT, ADC_SIGNALMODE_DIFFERENTIAL);

AdcaRegs.ADCCTL1.bit.INTPULSEPOS = 1;
AdcbRegs.ADCCTL1.bit.INTPULSEPOS = 1;
AdcdRegs.ADCCTL1.bit.INTPULSEPOS = 1; /

AdcaRegs.ADCCTL1.bit.ADCPWDNZ = 1;
AdcbRegs.ADCCTL1.bit.ADCPWDNZ = 1;
AdcdRegs.ADCCTL1.bit.ADCPWDNZ = 1;

DELAY_US(1000);

EDIS;
}

void SetupADCtimer0(void)
{
Uint16 acqps = 64;
/*
//determine minimum acquisition window (in SYSCLKS) based on resolution
if(ADC_RESOLUTION_12BIT == AdcaRegs.ADCCTL2.bit.RESOLUTION)
{
acqps = 14; // 75ns 采样保持时间
}
else
{
acqps = 80; // 320ns resolution is 16-bit
}
*/
EALLOW; // Select the channels to convert and end of conversion flag

/*******************************************************************************/
/* */
/* ADC-A */
/* */
/*******************************************************************************/
/*
AdcaRegs.ADCBURSTCTL.bit.BURSTEN = 1;
AdcaRegs.ADCBURSTCTL.bit.BURSTTRIGSEL = 1;
AdcaRegs.ADCBURSTCTL.bit.BURSTSIZE = 15;
*/
AdcaRegs.ADCSOC0CTL.bit.CHSEL = 0;
AdcaRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCSOC0CTL.bit.CHSEL = 1;
AdcaRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCSOC1CTL.bit.CHSEL = 2;
AdcaRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCSOC1CTL.bit.CHSEL = 3;
AdcaRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCSOC2CTL.bit.CHSEL = 4;
AdcaRegs.ADCSOC2CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC2CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCSOC2CTL.bit.CHSEL = 5;
AdcaRegs.ADCSOC2CTL.bit.ACQPS = acqps;
AdcaRegs.ADCSOC2CTL.bit.TRIGSEL = 1;

AdcaRegs.ADCINTSEL1N2.bit.INT1SEL = 5;
AdcaRegs.ADCINTSEL1N2.bit.INT1E = 1;
AdcaRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;

/*******************************************************************************/
/* */
/* ADC-B */
/* */
/*******************************************************************************/

// AdcbRegs.ADCBURSTCTL.bit.BURSTEN = 1;
// AdcbRegs.ADCBURSTCTL.bit.BURSTTRIGSEL = 1;
// AdcbRegs.ADCBURSTCTL.bit.BURSTSIZE = 2;

AdcbRegs.ADCSOC0CTL.bit.CHSEL = 0;
AdcbRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcbRegs.ADCSOC0CTL.bit.CHSEL = 1;
AdcbRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcbRegs.ADCSOC1CTL.bit.CHSEL = 2;
AdcbRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

AdcbRegs.ADCSOC1CTL.bit.CHSEL = 3;
AdcbRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

AdcbRegs.ADCSOC2CTL.bit.CHSEL = 14;
AdcbRegs.ADCSOC2CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC2CTL.bit.TRIGSEL = 1;

AdcbRegs.ADCSOC2CTL.bit.CHSEL = 15;
AdcbRegs.ADCSOC2CTL.bit.ACQPS = acqps;
AdcbRegs.ADCSOC2CTL.bit.TRIGSEL = 1;

// AdcbRegs.ADCINTSEL1N2.bit.INT1SEL = 0;
// AdcbRegs.ADCINTSEL1N2.bit.INT1E = 1;
// AdcbRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;

/*******************************************************************************/
/* */
/* ADC-D */
/* */
/*******************************************************************************/

// AdcdRegs.ADCBURSTCTL.bit.BURSTEN = 1;
// AdcdRegs.ADCBURSTCTL.bit.BURSTTRIGSEL = 1;
// AdcdRegs.ADCBURSTCTL.bit.BURSTSIZE = 2;

AdcdRegs.ADCSOC0CTL.bit.CHSEL = 0;
AdcdRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcdRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcdRegs.ADCSOC0CTL.bit.CHSEL = 1;
AdcdRegs.ADCSOC0CTL.bit.ACQPS = acqps;
AdcdRegs.ADCSOC0CTL.bit.TRIGSEL = 1;

AdcdRegs.ADCSOC1CTL.bit.CHSEL = 2;
AdcdRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcdRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

AdcdRegs.ADCSOC1CTL.bit.CHSEL = 3;
AdcdRegs.ADCSOC1CTL.bit.ACQPS = acqps;
AdcdRegs.ADCSOC1CTL.bit.TRIGSEL = 1;

// AdcdRegs.ADCINTSEL1N2.bit.INT1SEL = 0;
// AdcdRegs.ADCINTSEL1N2.bit.INT1E = 1;
// AdcdRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;

/*******************************************************************************/
/* */
/* ADC-interrupt configuration */
/* */
/*******************************************************************************/

// AdcaRegs.ADCINTSEL1N2.bit.INT1E = 1; // enable INT1 flag
// AdcaRegs.ADCINTSEL1N2.bit.INT2E = 0; // disable INT2 flag
// AdcaRegs.ADCINTSEL3N4.bit.INT3E = 0; // disable INT3 flag
// AdcaRegs.ADCINTSEL3N4.bit.INT4E = 0; // disable INT4 flag

AdcaRegs.ADCINTSEL1N2.bit.INT1CONT = 0;
AdcaRegs.ADCINTSEL1N2.bit.INT2CONT = 0;
AdcaRegs.ADCINTSEL3N4.bit.INT3CONT = 0;
AdcaRegs.ADCINTSEL3N4.bit.INT4CONT = 0;

AdcaRegs.ADCINTSEL1N2.bit.INT1E = 1; // enable INT1 flag
AdcaRegs.ADCINTFLGCLR.bit.ADCINT1 = 1; // make sure INT1 flag is cleared

EDIS;
}

AD结果寄存器值分别为49234 49426 49362，使用3V电压基准，通道实际电压为分压后的1.5V,像49426换算后结果已经到1.525V，存在很大偏差，我想确认上面的配置方法是否正确，如果不对应该如何配置？为什么采样结果误差很大（采样通道没有任何外接滤波电路），谢谢！

HeiHei：

这个问题不能单纯的从软件去找原因，还与你的外部电路设计有很大的关系，建议你把电路也贴出来另外你用的是哪几个ad通道