TMS320F28379D: ADC读取DAC输出时结果有偏差

您好，

我在用28379D Launch Pad的ADC读取DAC输出时结果对不上，如下图DAC输出3000.ADC读取为2924

请问这个该如何校准？

下面是我的代码

//
// Included Files
//
#include "F28x_Project.h"

typedef unsigned char Uint8;
//
// Function Prototypes
//
void ConfigureADC(void);
void SetupADCContinuous();

void configureDAC();

void gpio_init();

//
// Globals
//
Uint16 AdcaResult;

Uint16 dacval = 3000;

void main(void)
{InitSysCtrl();InitGpio(); // Skipped for this exampleDINT;InitPieCtrl();IER = 0x0000;IFR = 0x0000;InitPieVectTable();configureDAC();

//
// Configure the ADC and power it up
//ConfigureADC();

//
// Setup the ADC for continuous conversions on channel 0
//SetupADCContinuous();

//
// Enable global Interrupts and higher priority real-time debug events:
//EINT;  // Enable Global interrupt INTMERTM;  // Enable Global realtime interrupt DBGM

//
// take conversions indefinitely in loop
//do{DacaRegs.DACVALS.all = dacval;//选DAC?DELAY_US(2);////enable ADCINT flags//EALLOW;AdcaRegs.ADCINTSEL1N2.bit.INT2E = 1;AdcaRegs.ADCINTFLGCLR.all = 0x0002;EDIS;////software force start SOC0//AdcaRegs.ADCSOCFRC1.all = 0x0001;AdcaResult = AdcaResultRegs.ADCRESULT0;////disable all ADCINT flags to stop sampling//EALLOW;AdcaRegs.ADCINTSEL1N2.bit.INT2E = 0;EDIS;}while(1);
}

//
// ConfigureADC - Write ADC configurations and power up the ADC for both
//ADC A and ADC B
//
void ConfigureADC(void)
{EALLOW;////write configurations//AdcaRegs.ADCCTL2.bit.PRESCALE = 6; //set ADCCLK divider to /4AdcSetMode(ADC_ADCA, ADC_RESOLUTION_12BIT, ADC_SIGNALMODE_SINGLE);////Set pulse positions to late//AdcaRegs.ADCCTL1.bit.INTPULSEPOS = 1;////power up the ADC//AdcaRegs.ADCCTL1.bit.ADCPWDNZ = 1;////delay for 1ms to allow ADC time to power up//DELAY_US(1000);EDIS;
}

//
// SetupADCContinuous - setup the ADC to continuously convert on one channel
//
void SetupADCContinuous()
{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}EALLOW;AdcaRegs.ADCSOC0CTL.bit.CHSEL  = 2;  //SOC will convert on channel A2AdcaRegs.ADCSOC0CTL.bit.ACQPS  = acqps;//sample window is acqps +//1 SYSCLK cyclesAdcaRegs.ADCINTSEL1N2.bit.INT2E = 0; //disable INT2 flagAdcaRegs.ADCINTSEL1N2.bit.INT2CONT = 0;AdcaRegs.ADCINTSEL1N2.bit.INT2SEL = 14; //end of SOC14 will set INT2 flag////ADCINT2 will trigger first 8 SOCs//AdcaRegs.ADCINTSOCSEL1.bit.SOC0 = 2;EDIS;
}

void configureDAC()
{EALLOW;DacaRegs.DACCTL.bit.DACREFSEL = 1;//参考电压选择 0：VDAC/VSSA 1:VREFHI/VREFLODacaRegs.DACOUTEN.bit.DACOUTEN = 1;//DAC输出使能DacaRegs.DACVALS.all = 0;//影子寄存器DELAY_US(10); // Delay for buffered DAC to power upEDIS;
}

Yale Li：

能否多重复几次实验，得到尽可能多的实验结果？