Want to send value on a particular register using SPI

[Meera Shah]

void spi_read_write(0x1E,0x00) ==> output 0x10 as return value of register read.

Here I want to send value 0x90 as register value in the argument of spi_read_write(0x1E, 0x90) function, after  sending this it is retaining  0x10 as a rx_data buffer. Here is my code

static spi_rx_data[2] = {0x00,0x00};

void init(void)
{
    spi_read_write(ACCEL_WHO_M_I,0x00);  //this is working perfectly
    spi_read_write(ACCEL_REG_CTRL0,0x00); //return value spi_rx_data = 0xff,0x10
    
    spi_read_write(ACCEL_REG_CTRL0,0x90); //return value spi_rx_data = 0xff,0x10 also returning 0x10 previous value instead of 0x90
}

void spi_read_write(uint8_t register_pointer, uint8_t register_value)
{
    ret_code_t err_code;
    uint8_t data[2] ={0};
    uint8_t rx_buf;
   
    memset(spi_rx_data,0x00,sizeof(spi_rx_data));
    
    register_pointer |= 0x80;
    
    data[0] = register_pointer;
    data[1] = register_value;
    
    
    err_code = nrf_drv_spi_transfer(&spi, data,sizeof(data), spi_rx_data,sizeof(spi_rx_data));
    NRF_LOG_HEXDUMP_INFO(spi_rx_data,sizeof(spi_rx_data));
    APP_ERROR_CHECK(err_code);  
   
} 

[Jørgen Holmefjord]

Hi,

If you have initialized the SPI driver in non-blocking mode (by providing an event handler to nrf_drv_spi_init), you will have to wait for one transfer to complete before starting a new one (by calling spi_read_write_reg()/spi_read_write()). Please reference the SPI master example in the SDK on how to do this.

Best regards,
Jørgen

[Jørgen Holmefjord]

Delays does not guarantee that the transfer is completed. You should wait for the done event in the event handler.

[Meera Shah]

But I am using blocking mode(so no interrupt). spi_rx_data should come up with the updated register value. Please help me with this.