[求助] ADS7824 软件驱动调试，测量AD值错误

tomsx 2018-12-26 23:39 楼主

ADS7824调试时，ADC没有接电压源时，读取值为0x3437，计算值-0.32V，接电压3.3V时，读取值也大约-1.6V，
有没有调试过ADS7824的，原看看驱动和电路有没有问题?

#include "ADS7824.h"
#include "system.h"
#include "altera_avalon_pio_regs.h"
#include <stdlib.h>
#include <unistd.h>
#define BYTE_H() IOWR_ALTERA_AVALON_PIO_DATA(ADC_BYTE_BASE , 1 );
#define BYTE_L() IOWR_ALTERA_AVALON_PIO_DATA(ADC_BYTE_BASE , 0 );
#define CONTC_H() IOWR_ALTERA_AVALON_PIO_DATA(ADC_CONTC_BASE , 1 );
#define CONTC_L() IOWR_ALTERA_AVALON_PIO_DATA(ADC_CONTC_BASE , 0 );
#define CS_H() IOWR_ALTERA_AVALON_PIO_DATA(ADC_CS_BASE , 1 );
#define CS_L() IOWR_ALTERA_AVALON_PIO_DATA(ADC_CS_BASE , 0 );
#define RC_H() IOWR_ALTERA_AVALON_PIO_DATA(ADC_RC_BASE , 1 );
#define RC_L() IOWR_ALTERA_AVALON_PIO_DATA(ADC_RC_BASE , 0 );
#define BUSY() (IORD_ALTERA_AVALON_PIO_DATA(ADC_BUSY_BASE))
int ADS7824_Init(void)
{
RC_H()
CS_H()
IOWR_ALTERA_AVALON_PIO_DATA(ADC_CONTC_BASE , 0 );
return 0;
}
unsigned char ADS7824_Read8Bit(void)
{
unsigned char ADC_Value = 0;
unsigned int bit0 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D0_BASE);
unsigned int bit1 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D1_BASE);
unsigned int bit2 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D2_BASE);
unsigned int bit3 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D3_BASE);
unsigned int bit4 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D4_BASE);
unsigned int bit5 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D5_BASE);
unsigned int bit6 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D6_BASE);
unsigned int bit7 = IORD_ALTERA_AVALON_PIO_DATA(ADC_D7_BASE);
ADC_Value = (bit7 << 7)|(bit6 << 6)|(bit5 << 5)|(bit4 << 4)|(bit3 << 3)|(bit2 << 2)|(bit1 << 1)| (bit0 << 0);
//printf("ADC_Value=0x%X\n",ADC_Value);
return ADC_Value;
}
int ADS7824_Select_Channel(int channel )
{
// Channel Address. Input if CONTC LOW, output if CONTC HIGH. See Table I.
IOWR_ALTERA_AVALON_PIO_DATA(ADC_CONTC_BASE , 0 );
switch(channel )
{
case 0:
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A1_BASE , 0 );
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A0_BASE , 0 );
break;
case 1:
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A1_BASE , 0 );
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A0_BASE , 1 );
break;
case 2:
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A1_BASE , 1 );
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A0_BASE , 0 );
break;
case 3:
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A1_BASE , 1 );
IOWR_ALTERA_AVALON_PIO_DATA(ADC_A0_BASE , 1 );
break;
default:
return -1;
break;
}
return 0;
}
float ADS7824_GetFloatValue(int channel )
{
short AdValue = ADS7824_GetValue(channel);
float Value = 0;
if ( (AdValue & 0x0800)==0x0800 )
{
AdValue = AdValue& 0xF7FF;
AdValue = (AdValue^0x07FF)+1;
Value = 0-AdValue* 0.00048;
}
else
{
Value = AdValue * 0.00048;
}
return Value;
}
unsigned short ADS7824_GetValue(int channel)
{
unsigned short ADC_Data = 0;
unsigned char ADCDataH,ADCDataL;
ADS7824_Select_Channel(channel);
while(BUSY()==0)
{
}
CS_H()
RC_H()
usleep(1);
RC_L()
CS_L()
usleep(12);
while(BUSY()==0)
{
}
CS_H()
RC_H()
CS_L()
usleep(1);
BYTE_L()
usleep(1);
ADCDataH = ADS7824_Read8Bit();
//printf("ADCDataH=%X\n",ADCDataH);
CS_H()
usleep(1);
CS_L()
BYTE_H()
ADCDataL = ADS7824_Read8Bit();
//printf("ADCDataL=%X\n",ADCDataL);
ADC_Data = ((unsigned int)ADCDataH << 4) | (( (unsigned int)ADCDataL >>4)&0x0F) ;
//printf("ADC_Data=%X\n",ADC_Data);
CS_H()
usleep(250);
return ADC_Data;
}