[参考译文] ADS1256：切换 ADS1256输入多路复用器时获得随机尖峰

/******************************************************************************
function: Set the channel to be read
parameter:
Channal : Set channel number
Info:
******************************************************************************/


void ADS1256_SetDiffChannal(UBYTE Channal)
{
if (Channal == 0){
ADS1256_WriteReg(REG_MUX, (0 << 4) | 1); //DiffChannal AIN0-AIN1

}
else if(Channal == 1){
ADS1256_WriteReg(REG_MUX, (2 << 4) | 3); //DiffChannal AIN2-AIN3

}
else if(Channal == 2){
ADS1256_WriteReg(REG_MUX, (4 << 4) | 5); //DiffChannal AIN4-AIN5

}
else if(Channal == 3){
ADS1256_WriteReg(REG_MUX, (6 << 4) | 7); //DiffChannal AIN6-AIN7

}
}


******************************************************************************/
static UDOUBLE ADS1256_Read_ADC_Data(void)
{
UDOUBLE read = 0;
UBYTE buf[3] = {0,0,0};


DEV_Digital_Write(DEV_CS_PIN, 0);
DEV_Delay_us(1);

ADS1256_WaitDRDY();
DEV_SPI_WriteByte(CMD_RDATA);
DEV_Delay_us(7);
buf[0] = DEV_SPI_ReadByte();
buf[1] = DEV_SPI_ReadByte();
buf[2] = DEV_SPI_ReadByte();


read = ((UDOUBLE)buf[0] << 16) & 0x00FF0000;
read |= ((UDOUBLE)buf[1] << 8); /* Pay attention to It is wrong read |= (buf[1] << 8) */
read |= buf[2] ;

DEV_Digital_Write(DEV_CS_PIN, 1);
return read;
}

/******************************************************************************
function: Read ADC specified channel data
parameter:
Channel: Channel number
Info:
******************************************************************************/
UDOUBLE ADS1256_GetChannalValue(UBYTE Channel)
{
UDOUBLE Value = 0;
ADS1256_WaitDRDY();

if(Channel>=4){
return 0;
}
if(channel ==1){
ADS1256_SetDiffChannal(Channel);

Value = ADS1256_Read_ADC_Data();
}
else{
ADS1256_SetDiffChannal(Channel);

DEV_Delay_us(4);
ADS1256_WriteCmd(CMD_SYNC);
DEV_Delay_us(4);
ADS1256_WriteCmd(CMD_WAKEUP);

DEV_Delay_us(1);
Value = ADS1256_Read_ADC_Data();
}

return Value;
}

/******************************************************************************
function: Read data from all channels
parameter:
ADC_Value : ADC Value
Info:
******************************************************************************/
void ADS1256_GetAll(UDOUBLE *ADC_Value)
{
UBYTE i;
for(i = 0; i<channel; i++){
ADS1256_WaitDRDY();
ADC_Value[i] = ADS1256_GetChannalValue(i);
}

}