SPI pin on nrf51 DK

RE: SPI pin on nrf51 DK

Jørgen Holmefjord — Thu, 02 Mar 2017 08:53:10 GMT

The SPI PCA10028 examle in SDK 11 use SPI instance 0, with the following default config in nrf_drv_config.h:

#define SPI0_CONFIG_SCK_PIN 1
#define SPI0_CONFIG_MOSI_PIN 2
#define SPI0_CONFIG_MISO_PIN 3

Using #define SPI_CS_PIN 4 with this configuration should therefore not be an issue, unless you have made any changes to nrf_drv_config.h.

RE: SPI pin on nrf51 DK

anthony — Wed, 01 Mar 2017 15:40:43 GMT

Hi, i used the SDK_v11 and in the example "peripheral\spi\pca10028" in the main, it's written : nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG(SPI_INSTANCE); spi_config.ss_pin = SPI_CS_PIN; (SPI_CS_PIN = 4) so there'is a problem, because in the nrf_drv_config.h the pin 4 is used for the MISO signal. So what is the pin number of the CS (chipselect)?

best regards

RE: SPI pin on nrf51 DK

Yacire — Mon, 03 Oct 2016 11:22:05 GMT

Thanks Jorgen, it's very clear now, how SPI pin definition works.

RE: SPI pin on nrf51 DK

Jørgen Holmefjord — Mon, 03 Oct 2016 11:08:35 GMT

Yes, in the SPI Loopback example in SDK10 it is correct that the pins from BSP is used. If you look at the function spi_master_init(..) in main.c, you can see that the nrf_drv_spi_config_t is set to use the pin numbers defined in pca10028.h. If you change the example to use the default config using nrf_drv_spi_config_t config = NRF_DRV_SPI_DEFAULT_CONFIG(0);, as described in the spi master driver documentation, the pins from the defined in nrf_drv_config.h would have been used. It all depends on how the SPI interface is configured.

RE: SPI pin on nrf51 DK

Yacire — Fri, 30 Sep 2016 17:15:04 GMT

Are you sure ?

I tested the SPI Master LoopBack example and it is the pins defined in the bsp.h file who are used for SPI... Not those in the nrf_drv_config.h

Can you test the example in the SDK 10 ? connect pin 1 and 3 for SPI0, and 12 and 14 for SPI1 and it works.

But if you look in the nrf_drv_config, you can see the SPI0 and SPI1 are enabled and the pin mapping is the same: pin 2 3 and 4.

I don't understand. Thanks.

RE: SPI pin on nrf51 DK

Jørgen Holmefjord — Fri, 30 Sep 2016 10:29:48 GMT

No, the defines in nrf_drv_config.h is used to setup the SPI interface (given that you are using the SPI master driver). If you want to use the pins defined in BSP, you need to change the defines in nrf_drv_config.h to:

#define SPI0_CONFIG_SCK_PIN SPIM0_SCK_PIN

#define SPI0_CONFIG_MOSI_PIN SPIM0_MOSI_PIN

#define SPI0_CONFIG_MISO_PIN SPIM0_MISO_PIN

RE: SPI pin on nrf51 DK

Yacire — Fri, 30 Sep 2016 09:56:56 GMT

Thanks for your answer Jorgen,

But i use bsp.h file, so my pin for the SPI interface are those defined in the pca10028.h right ? The pin defined in the nrf_drv_config.h are used if i don't use the bsp.h file ?

RE: SPI pin on nrf51 DK

Jørgen Holmefjord — Fri, 30 Sep 2016 06:54:05 GMT

Hi,

The pins on nRF51 (and nRF52) chips are reconfigurable via pin crossbar, meaning you can use any of the GPIO pins for any peripheral like SPI, UART, TWI, etc.

The defines in pca10028.h is just defines for default pinouts on the PCA10028 board, to easily be able to support for new boards in SDK. This is enabled by the Board Support Package.

The macros in nrf_drv_config.h is the actual configuration of the interface and its pins. If you change the pin numbers here, the new pins will be used for the SPI interface.

Best regards,

Jørgen