SPI Slave cannot receive data, sending data to master normally

[MLai]

Hi all,

I am using a custom board with NRF 52840 with SDK15.2 as slave and STM as master. I cannot receive right data, but the data to STM is right.

void spis_incoming_msg_packet_handling(uint8_t *tmp, int size) {
    for(int i = 0 ;i< size;i++)
          m_tx_buf[i+1] = tmp[i];
          tx_size = size;
    if(tmp[0]==0xAA){
     if(tmp[1] == 0x01 ||tmp[1] == 0x02){
       int tmp_size = (int) tmp[2];
       uint16_t tmpLength = (uint16_t)tmp_size;
       if(tmp[tmp_size+3] == 0xBB){
        for(int i = 0 ;i< tmp_size;i++){
          tx_data[i]=tmp[i+2];
          }
          m_length=size;
          if(isConnect)
            ble_nus_data_send(&m_nus, tx_data, &tmpLength, m_conn_handle);
             }
        }
    }
}
void spis_event_handler(nrf_drv_spis_event_t event) {
  if (event.evt_type == NRF_DRV_SPIS_XFER_DONE) {
    spis_xfer_done = true;
    printf("enter handler");
    spis_incoming_msg_packet_handling(m_rx_buf, 100);
  }
}

#if defined(SPI_MODULE)
void switchToSPIS() {

  printf("activating SPIS");
    nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;

    //spis_config.csn_pullup = NRF_GPIO_PIN_PULLUP; // Test 01
    //spis_config.csn_pullup = NRF_GPIO_PIN_NOPULL; // Test 02
    //spis_config.csn_pullup = NRF_GPIO_PIN_PULLDOWN; // Test 03

    spis_config.csn_pin = 4;  //29 //7  APP_SPIS_CS_PIN
    spis_config.miso_pin = 8; //28 // 8  APP_SPIS_MISO_PIN
    spis_config.mosi_pin = NRF_GPIO_PIN_MAP(1,9); //4 //  9  APP_SPIS_MOSI_PIN
    spis_config.sck_pin = 6;  //3 // 10 APP_SPIS_SCK_PIN
    nrf_drv_spis_init(&spis, &spis_config, spis_event_handler);

}

The above are the setup, and the following are the part that prepare buffer.

m_tx_buf[0] = 0xAA;
 m_tx_buf[tx_size-1]=0xCC;
nrf_drv_spis_buffers_set(&spis, m_tx_buf, tx_size, m_rx_buf, 100);

What I got from STM is AAFFFFF...00000CC, may I know what is the problem? As the code works on nrf 52832, just changing the pin. I am not sure if any config is set wrong.

Best regards,

Marco Lai

[Jørgen Holmefjord]

Hi,

I'm not sure if I understand what you are asking about. What is tx_size set to? If you set the first and last byte of the m_tx_buf array,I would expect you to get something like "AAFFFFF...00000CC", depending on what is in the buffer already.

• What are you expecting to receive from the STM?
• Have you checked the SPI lines with a logic analyzer, to see if the output is the same that you see in the application?
• Are you using the same SPI Mode configuration on both sides?
• What frequency is the SPI running at?

You can also possibly try different GPIOs and/or pull, and drive strength configurations for the pins.

Best regards,
Jørgen