NRF51822: nrf_drv_spi_transfer hangs

[Ivan Kolesnikov]

I have initialized SPI0 master by this code:

static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(0);
...		
nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin = SPIM0_SS_PIN;
spi_config.miso_pin = SPIM0_MISO_PIN;
spi_config.mosi_pin = SPIM0_MOSI_PIN;
spi_config.sck_pin = SPIM0_SCK_PIN;
spi_config.mode = NRF_DRV_SPI_MODE_1;
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, NULL));

Then I try to send some data via SPI:

uint8_t tx_buf[] = { 0x11 };
APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, tx_buf, sizeof(tx_buf), NULL, 0));

But my application hangs inside spi_xfer (in nrf_drv_spi.c) at this line:

while (!nrf_spi_event_check(p_spi, NRF_SPI_EVENT_READY)) {}

The strangest thing for me is sometimes my application works fine, but it rarely happens (the firmware can not be changed - the application can earn or vice versa start hanging after a few reboots).

What could be the problem?

[bjorn-spockeli]

Which pins are you using , i.e. what are SPIM0_SS_PIN, SPIM0_MISO_PIN, SPIM0_MOSI_PIN and SPIM0_SCK_PIN set to?

[Ivan Kolesnikov]

This is my pin defs:

#define SPIM0_SCK_PIN       23
#define SPIM0_MOSI_PIN      25
#define SPIM0_MISO_PIN      22
#define SPIM0_SS_PIN        24

[bjorn-spockeli]

Pin 23 is the SWDIO/nRESET pin and Pin 24 is the SWDCLK pin. You should use pins 14 to 22 or pins 25 to 28.

[Ivan Kolesnikov]

You are not quite right. This is the numbering of the GPIO port pins, not the pins on the package. They do not match.

[bjorn-spockeli]

You are correct, the P0.21 to P0.25 should be fine. Sorry for the misunderstanding. Where do you call nrf_drv_spi_transfer()? In mains or interrupt context, e.g. event handler of the app timer?