Problem of 52832 SPI interface

RE: Problem of 52832 SPI interface

Jørgen Holmefjord — Sun, 02 Feb 2020 19:02:04 GMT

There is a code example in this post. It is written for an older SDK version, but I do not think that the API of the drivers used have changed much in later SDKs.

RE: Problem of 52832 SPI interface

chianglin — Sun, 02 Feb 2020 05:33:24 GMT

Hi,

Thank you for your answer.

I still don't know how to fix this problem after I study "https://infocenter.nordicsemi.com/index.jsp?topic=%2Ferrata_nRF52832_EngC%2FERR%2FnRF52832%2FEngineeringC%2Flatest%2Fanomaly_832_58.html"

Would you please give me an sample code then I can fix this problem?

Thank you

Chianglin

RE: Problem of 52832 SPI interface

Dmitry — Wed, 29 Jan 2020 13:54:27 GMT

also take a look at this picture - you have CPOL=1 that means active low level of SCK, you should change this in your LA settings.

RE: Problem of 52832 SPI interface

Dmitry — Wed, 29 Jan 2020 13:32:48 GMT

seems you have catched this bug.

RE: Problem of 52832 SPI interface

chianglin — Wed, 29 Jan 2020 09:51:52 GMT

Hi,

a) My default SCK pin in sdk_config.h setting is:

#ifndef SPI_SCK_PIN
#define SPI_SCK_PIN 14
#endif

And my initialize setting in main() is:

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin   = SPI_SS_PIN;
    spi_config.miso_pin = SPI_MISO_PIN;
    spi_config.mosi_pin = SPI_MOSI_PIN;
    spi_config.sck_pin  = SPI_SCK_PIN;
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

NRF_DRV_SPI_DEFAULT_CONFIG is:

#define NRF_DRV_SPI_DEFAULT_CONFIG                           \
{                                                            \
    .sck_pin      = NRF_DRV_SPI_PIN_NOT_USED,                \
    .mosi_pin     = NRF_DRV_SPI_PIN_NOT_USED,                \
    .miso_pin     = NRF_DRV_SPI_PIN_NOT_USED,                \
    .ss_pin       = NRF_DRV_SPI_PIN_NOT_USED,                \
    .irq_priority = SPI_DEFAULT_CONFIG_IRQ_PRIORITY,         \
    .orc          = 0xFF,                                    \
    .frequency    = NRF_SPI_FREQ_500K,                     \
    .mode         = NRF_DRV_SPI_MODE_2,                      \
    .bit_order    = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST,         \
}

If I want to create following wave form, how can I modify my program?

b) I had modify my program by using your suggest method, please fine following program,

static uint8_t       m_tx_buf[1] = {'1'}

APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, 1, m_rx_buf, 1));

but, I found following wave-form output in Logic-analyzer.

The wave-form still not correct (output data and output length).

Would you please give me some suggestion?

Thank you

RE: Problem of 52832 SPI interface

Dmitry — Wed, 29 Jan 2020 09:03:01 GMT

Hi,

a) are you sure that your default config is taken from the right file? Your SCK pin behaves as in mode 1 - data is shifted with leading edge, sampling is expected at trailing one.

b) you're initializing uint8_t[] array with a string. Most compilers will give you an error here, but if your compiler didn't, it takes a sting as two bytes - including trailing zero character. The right way is:

static uint8_t m_tx_buf[1] = { '1' };