Chip Select pin in SDK 11.0

[Pradeep Chl]

In NRF52-DK, I am currently working on NRF5 SDK 11.0.

In examples/peripheral/spi/pca10040/, The master spi device is continuously sending "Nordic" string every 200msec to the slave.

My question is are you making Chip Select (CS) pin low every 200 msec when there is data to be sent or you are making it low all the time.?

Rgds,

[James Yu]

The CS pin is pulled low on nrf_drv_spi_transfer() and set high on spi_event_handler().

[Pradeep Chl]

CS pin is not set high in spi_event_handler(), It is a small function that is called after data is transferred from m_tx_buf. Please correct me.

At line no: 540 in nrf_drv_spi.c, the function nrf_gpio_pin_clear(p_cb->ss_pin) clears the CS pin.

Without EasyDMA: At line no: 415 in nrf_drv_spi.c, the function nrf_gpio_pin_set(p_cb->ss_pin) sets the CS pin.

With EasyDMA: At line no: 502 in nrf_drv_spi.c, the function nrf_gpio_pin_set(p_cb->ss_pin) sets the CS pin.

Clearing CS and Setting CS pin happens in the same function nrf_drv_spi_transfer() ?

Thanks,

[tesc]

Hi,

The SPI master example (examples\peripheral\spi) uses the SPI master driver. Slave select is handled by the driver, i.e. SPI_CS_PIN is set low right before the transfer starts and set back high when transfer is done.

Regards, Terje