为什么我的ADS1247读数不正常？

朋友们好 ，我最近在做 ads1247 这个芯片 我的SPI通讯是正常的 能够正确都出我写入的寄存器的值，但是读的书不正确 附上我的 电路图 和 测试波形 请问 这种情况 是怎么回事 啊 我测了差分输入和电压基准输入都没问题的 我的电阻计算公式是 RTD=(D24*820)/(Gain*8388608);
#include "ADS1247FUNC tiON.h"
#include "usart1.h"
#include "BSP_LED.H"
char Reg_cmd;
uint8_t WaitBusy()
{
char i;
i = 0;
while(ADS1247_DRDY_Val)
{
i++;
if(i > 20)
return 1;
}
return 0;
}
void ADS1247_init(void) //ζȳõʼ»¯
{

ADS1247_CS_0; /****Ïȸ´Î»****/
ADS1247_WriteCmd(ADC_CMD_RESET);
ADS1247_CS_1;
delay_ms(50); //ÖÁÉÙ0.6ms

Reg_cmd=0x0a; // AIN1¡¢AIN2·Ö±ðÉèÖÃΪ²ÉÑùÕý¸ºÊäÈë¶Ë
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_MUX0);
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;
Reg_cmd=0x00;
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_VBIAS);//¹Ø±ÕÆ«Öõçѹ
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;
Reg_cmd=0x20; //Ñ¡ÔñÄÚ²¿²Î¿¼µçѹ
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_MUX1);
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;

Reg_cmd=0x20; //ÔöÒæ ²ÉÑùÂÊΪ ºóÐøÐÞ¸ÄÕâ¸öÖµ½øÐе÷ÊÔ
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_SYS0);
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;

Reg_cmd=0x0E; //ÉèÖÃIDAC0Ϊ1mA ¸´ÓÃDOUT/DRDYÒý½Å
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_IDAC0);
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;
Reg_cmd=0x03; //AIN0ΪµÚÒ»µçÁ÷Ô´Êä³ö AIN3ΪµÚ¶þµçÁ÷Ô´Êä³ö
ADS1247_CS_0;
Delay(50);
ADS1247_WriteCmd(ADC_CMD_WREG|ADS1247_REG_IDAC1);
ADS1247_WriteCmd(0x00);
ADS1247_WriteCmd(Reg_cmd);
ADS1247_CS_1;
/*¶Á¼Ä´æÆ÷Öµ²¢ÏÔʾ³öÀ´*/
uint16_t MUX0,VBIAS,MUX1,SYS0,IDAC0,IDAC1;
ADS1247_CS_0; //¸´Î»ºóÒªÏÈÑÓʱ ÖÁÉÙ10ns
Delay(50);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_MUX0);
ADS1247_WriteCmd(0x00);
MUX0=ADS1247_ReadCmd(ADC_CMD_NOP);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_VBIAS);
ADS1247_WriteCmd(0x00);
VBIAS=ADS1247_ReadCmd(ADC_CMD_NOP);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_MUX1);
ADS1247_WriteCmd(0x00);
MUX1=ADS1247_ReadCmd(ADC_CMD_NOP);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_SYS0);
ADS1247_WriteCmd(0x00);
SYS0=ADS1247_ReadCmd(ADC_CMD_NOP);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_IDAC0);
ADS1247_WriteCmd(0x00);
IDAC0=ADS1247_ReadCmd(ADC_CMD_NOP);

WaitBusy();
ADS1247_WriteCmd(ADC_CMD_RREG|ADS1247_REG_IDAC1);
ADS1247_WriteCmd(0x00);//Í˳ö˯Ãßģʽ
IDAC1=ADS1247_ReadCmd(ADC_CMD_NOP);
printf("rn MUX0 %x", MUX0);//Êä³ö16½øÖÆÎÞ·ûºÅÕûÊý
printf("rn VBIAS %x", VBIAS);
printf("rn MUX1 %x", MUX1);
printf("rn SYS0 %x", SYS0);//Êä³ö16½øÖÆÎÞ·ûºÅÕûÊý
printf("rn IDAC0 %x", IDAC0);
printf("rn IDAC1 %x", IDAC1);
ADS1247_WriteCmd(ADC_CMD_NOP);

ADS1247_CS_1;
}
void SPI1_ReadReg(char RegAddr,char *Buffer,char Length)
{
char Cmd[2];
ADS1247_CS_0;
Cmd[0]=ADC_CMD_RREG|RegAddr;
Cmd[1]=Length-1;
SPI1_WriteBytes(Cmd,2);
SPI1_ReadBytes(Buffer,Length);
/******·¢Ò»¸öNOPÃüÁî¿ÉÒÔÇ¿ÖÆDOUTÒý½ÅÊä³ö¸ßµçƽ******/
Cmd[0]=ADC_CMD_NOP;
SPI1_WriteBytes(Cmd,1);
ADS1247_CS_1;
}
void SPI1_WriteReg(char RegAddr,char *Buffer,char Length)
{
char Cmd[2];
ADS1247_CS_0;
Cmd[0]=ADC_CMD_WREG|RegAddr;
Cmd[1]=Length-1;
SPI1_WriteBytes(Cmd,2);
SPI1_WriteBytes(Buffer,Length);
/******·¢Ò»¸öNOPÃüÁî¿ÉÒÔÇ¿ÖÆDOUTÒý½ÅÊä³ö¸ßµçƽ******/
//Cmd[0]=ADC_CMD_NOP;
//SPI1_WriteBytes(Cmd,1);
ADS1247_CS_1;
}
void SPI1_WriteBytes(char *TxBuffer,char TxLenth)
{
char Temp=0;
while(TxLenth--)
{
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI1->DR=*TxBuffer++;
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
Temp=(char)SPI1->DR; //ÕâÒ»²½ÊÇʲôÒâ˼
}
Temp++; //±ÜÃâkeil-MKD²úÉú±àÒ뾯¸æ
}
void SPI1_ReadBytes(char *RxBuffer,char RxLenth)
{
while(RxLenth--)
{
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI1->DR=*RxBuffer;
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
*RxBuffer++=(char)SPI1->DR;
}
}
char ADS1247_ReadCmd(char Cmd)
{
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI1->DR=Cmd;
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
return SPI_I2S_ReceiveData(SPI1);
}
char ADS1247_Return_read_val(char Cmd) //cx AD²ÉÑù¶ÁÊý¾ÝÓõĺ¯Êý
{
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI1->DR=Cmd;
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
return SPI_I2S_ReceiveData(SPI1);
}
void ADS1247_WriteCmd(char Cmd)
{
char Temp;

while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);//µÈ´ý·¢ËÍ»º³åÇøΪ¿ÕTXEʼþ
SPI1->DR=Cmd;
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);//µÈ´ý½ÓÊÕ»º³åÇøΪ¿Õ
Temp=(char)SPI1->DR; //ÕâÒ»²½ÊÇʲôÒâ˼ ÕâÒ»²½ÊǶÁÈ¡·µ»ØÀ´µÄÊý¾Ý

Temp++; //±ÜÃâkeil-MKD²úÉú±àÒ뾯¸æ
//ADS1247_CS_1;
}
// AD¶ÁÊý¾Ý
//uint32_t ADS1247_Read_once(void)
//{
//
// uint32_t T_D24,RTD;
// char Return_val[4];
// char DATA_Cmd = ADC_CMD_RDATA;
// //Cmd[0]=ADC_CMD_RDATAC;
// Return_val[0] = ADC_CMD_NOP;
// Return_val[1] = ADC_CMD_NOP;
// Return_val[2] = ADC_CMD_NOP;
// Return_val[3] = ADC_CMD_NOP;
//
// ADS1247_CS_0;
// delay_us(50);
// SPI1_WriteBytes(&DATA_Cmd,1);
// while(WaitBusy()); //Á¬Ðøģʽ¿ÉÄÜÓõ½
//
// Return_val[0] = ADS1247_Return_read_val(ADC_CMD_NOP);
// Return_val[1] = ADS1247_Return_read_val(ADC_CMD_NOP);
// Return_val[2] = ADS1247_Return_read_val(ADC_CMD_NOP);
// Return_val[3] = ADS1247_Return_read_val(ADC_CMD_NOP);
//
// ADS1247_CS_1;
//
// T_D24 = (Return_val[0]<<16) | (Return_val[1]<<8) | Return_val[2];//SPIÒ»´ÎͨѶֻÄÜ·µ»ØÒ»¸ö×Ö½ÚµÄÊý¾Ý
// T_D24 &= 0x00FFFFFF;//ADÊÇ24λоƬ È¡³ö24λÊý¾Ý
// RTD=(205*T_D24)/16777216;
// printf("rn RTD %d", RTD);
//}
uint32_t ADS1247_Read_once(void)
{
//GPIO_ResetBits(GPIOC, GPIO_Pin_11);
uint32_t D24,RTD,T;
uint32_t Return_val_0,Return_val_1,Return_val_2,Return_val_3;

// Return_val_1=ADC_CMD_NOP;
// Return_val_2=ADC_CMD_NOP;
// Return_val_3=ADC_CMD_NOP;
// Return_val_4=ADC_CMD_NOP;

//while(WaitBusy())
// ;

ADS1247_CS_0;
Delay(50);

while(WaitBusy());
// ADS1247_WriteCmd(0x00);
Return_val_0=ADS1247_ReadCmd(ADC_CMD_RDATA);//µ¥´Î¶ÁÈ¡Êý¾Ý
Delay(50);

Return_val_1 = ADS1247_Return_read_val(ADC_CMD_NOP);
Return_val_2 = ADS1247_Return_read_val(ADC_CMD_NOP);
Return_val_3 = ADS1247_Return_read_val(ADC_CMD_NOP);
//Return_val_4 = ADS1247_Return_read_val(ADC_CMD_NOP);

ADS1247_CS_1;
printf("rn Return_val_1 %x", Return_val_1);//Êä³ö16½øÖÆÎÞ·ûºÅÕûÊý
printf("rn Return_val_2 %x", Return_val_2);
printf("rn Return_val_3 %x", Return_val_3);
//printf("rn Return_val_4 %x", Return_val_4);
// Return_val_0= (Return_val_1&0x80)!=0 ? 0xFF:0x00;
// printf("rn Return_val_0 %x", Return_val_0);

D24 = ((Return_val_1<<16)|(Return_val_2<<8)|Return_val_3)&0x00ffffff;
//D24 = Return_val_0|(Return_val_2<<8)|Return_val_3;
//return D24;
RTD=(D24*820)/(4*8388608);
printf("rn RTD %d", RTD);
// T=(RTD-100)/0.385;
// printf("rn TN %d", T);
}