SPI slave

RE: SPI slave

henryh — Wed, 10 Apr 2019 20:13:24 GMT

I have resolved this issue and it was a data problem. I assumed that the incoming data could not be all '0' and this led me to assume I was not receiving data. The data was from an ADC but switching to a logic signal at the MOSI pin (one synchronized to the SPIS clock) allowed me to verify that the SPIS peripheral was working correctly. Now to figure out why the ADC is acting like that... :-)

RE: SPI slave

henryh — Wed, 10 Apr 2019 13:34:29 GMT

Thanks for the suggestion but I have done a thorough timing analysis and it is definitely mode "0". In this case I should see some data (even if it is mangled) but all am getting is "0".

RE: SPI slave

Edvin — Mon, 08 Apr 2019 14:49:54 GMT

Hello,

Can you try all the SPI modes?

NRF_DRV_SPIS_DEFAULT_CONFIG sets .mode = NRF_SPIS_MODE_0.

Maybe your other devices uses one of the other modes?

/**
 * @brief SPI modes.
 */
typedef enum
{
    NRF_SPIS_MODE_0, ///< SCK active high, sample on leading edge of clock.
    NRF_SPIS_MODE_1, ///< SCK active high, sample on trailing edge of clock.
    NRF_SPIS_MODE_2, ///< SCK active low, sample on leading edge of clock.
    NRF_SPIS_MODE_3  ///< SCK active low, sample on trailing edge of clock.
} nrf_spis_mode_t;

Try setting e.g. NRF_SPIS_MODE_1:

    nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
    spis_config.mode                  = NRF_SPIS_MODE_1;
    spis_config.csn_pin               = APP_SPIS_CS_PIN;
    spis_config.miso_pin              = APP_SPIS_MISO_PIN;
    spis_config.mosi_pin              = APP_SPIS_MOSI_PIN;
    spis_config.sck_pin               = APP_SPIS_SCK_PIN;

And of course, test the ..._MODE_2 and ..._MODE_3 as well.

Best regards,

Edvin