ADS1292: Read/Write ADS1292

Hi, 

I'm trying to interface my ADS1292 with PSoC, however, I'm not able to read the register values (even the ID register returns 0x00).

Note that the ADS is functioning with default configurations. We're facing this issue with multiple ADS1292 chips.

These are the steps I followed while debugging:

1. Power-up sequence mentioned in the datasheet. 

2. Added delay as mentioned in a few other questions in the TI forum.

3. Checked the values of VCAP1, VCAP2, and VRef.

4. Probed the MISO/ CS/SCLK/DRDY lines and checked on the oscilloscope.

This is the code I have used:

0. Initialization

//Defines for Commands.
#define WakeUpCmd           0x02
#define StandByCmd          0x04
#define ResetCmd            0x06
#define StartCmd            0x08
#define StopCmd             0x0A
#define SDATACCmd           0x11
#define RDATACmd            0x12
#define ReadRegCmd          0x20
#define WriteRegCmd         0x40
// Defines for Register Addresses.
#define ID_Addr             0x00
#define CONFIG1_Addr        0x01
#define CONFIG2_Addr        0x02
#define CH1SET_Addr         0x04
#define CH2SET_Addr         0x05
#define RLDSENS_Addr        0x06
#define RESP1               0x09
#define RESP2               0x0A

1. Function for ADS Configuration

void my_ads_config(void)
{
    uint8 temp;
    
    /*Power UP Sequence*/
    Pin_MISO_Write(0);
    Pin_MOSI_Write(1);
    Pin_SCLK_Write(0);
    Pin_DRDY_Write(1);
    Pin_SS_Write(1);
    Pin_PWDN_Write(0);
    Pin_Start_Write(0);
    
    /*Wait for Tpor=1s*/
    CyDelay(1000);
    
    /*Set CLK=1*/
    Pin_SCLK_Write(1);
    
    /*Wait for Tpor=1s*/
    CyDelay(1000);
    
    /*RESET PULSE*/
    Pin_PWDN_Write(1);
    CyDelay(1000);
    Pin_PWDN_Write(0);
    CyDelay(1000);
    Pin_PWDN_Write(1);
    CyDelay(100);
    
    /*Reset communication*/
    Pin_SS_Write(0);
    CyDelay(1000);
    Pin_SS_Write(1);
    CyDelay(500);
    
    /* stop read data continous mode */
    SendCommand(SDATACCmd);
    CyDelay(10);
    
    /*Read ID register*/
    temp = ReadRegister(0x00);
    
    /* using internal buffer*/
    WriteRegister(CONFIG2_Addr, 0xA0);
    CyDelayUs(10);
    temp = ReadRegister(0x02);
 
    SendCommand(StartCmd);
}

2. Function to Read Register

uint8 ReadRegister (uint8_t ui8RegAddress)
{
    uint8_t tx_buf [3];
    uint8_t rx_buf[3];
    const uint8_t PACKET_SIZE = 3;
    Pin_SS_Write(0);
     
    /* Send write register command appended with the register address. */
    tx_buf[0] = ReadRegCmd | ui8RegAddress;
    CyDelayUs(5);
    tx_buf[1] = 0;
    CyDelayUs(5);
    tx_buf[2] =  0;
    CyDelayUs(5);
    
    /* start transfer */
    SPIM_ads_SpiUartPutArray(tx_buf, PACKET_SIZE);
    
    /* wait for the end of the transfer */
    while(PACKET_SIZE != SPIM_ads_SpiUartGetRxBufferSize());
    
    Pin_SS_Write(1);
    
    /* read RX buffer */
    rx_buf[0] = (uint8) SPIM_ads_SpiUartReadRxData();
    rx_buf[1] = (uint8) SPIM_ads_SpiUartReadRxData();
    rx_buf[2] = (uint8) SPIM_ads_SpiUartReadRxData();
    
    
    /* clear dummy bytes from RX buffer */
    SPIM_ads_SpiUartClearRxBuffer();
    
    /* return the register content */
    return(rx_buf[2]);
}

3. Function to write register

void WriteRegister (uint8_t ui8RegAddress, uint8_t ui8RegData)
{
    uint8_t tx_buf [3];
    const uint8_t PACKET_SIZE = 3;
  
    /* Send write register command appended with the register address. */
    tx_buf[0] = WriteRegCmd | ui8RegAddress;
    CyDelayUs(5);
    tx_buf[1] = 0;
    CyDelayUs(5);
    tx_buf[2] = ui8RegData;
    CyDelayUs(5);
    
    /* start transfer */
    SPIM_ads_SpiUartPutArray(tx_buf, PACKET_SIZE);
    
    /* wait for the end of the transfer */
    while(PACKET_SIZE != SPIM_ads_SpiUartGetRxBufferSize());
    
    /* clear dummy bytes from RX buffer */
    SPIM_ads_SpiUartClearRxBuffer();
}