implement 2 hardware SPI

[yuval]

i want to implement 2 hardware SPI communication in my code. i have one already working. talking with LCD ILI9341. the functions are using spi_write /  nrf_drv_spi_transfer for a single interface.  what do i need to do to add another (4 pin) SPI interface to communicate with accelerometer. do i need to change it to SPI1 and then duplicate everything to SPI2 ?

thanks

Yuval

[Susheel Nuguru]

You do not need to add another 4 pins, you can still use the same 4 pins to communicate with the accelerometer, but you need a new slave select pin for sending the data  to this slave. Please take a look at slave configuration at the wiki

[yuval]

i already have another 4 pins connected to the acc chip:
#define LSM6DS3_MOSI_PIN 12
#define LSM6DS3_MISO_PIN 13
#define LSM6DS3_SCK_PIN 14
#define LSM6DS3_SS_PIN 15

my question is , does anyone have a code example of using 2 different SPI ?

[hmolesworth]

If you are using standard Nordic libraries and so on then you just need to use a new instance and duplicate the code. ie if you are doing something like this:

APP_ERROR_CHECK(nrf_drv_spi_init(&mAccSpiInstance, &spi_config, acc_spi_event_handler, NULL));

Then all you need to do is duplicate the code - typically in a separate c module - and use a new instance thus:

#define SPI_INSTANCE  1   // SPI instance index for 2nd SPI
static const nrf_drv_spi_t mAccSpiInstance = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);

Ensure SPI1 is also enabled in sdk_config.h, of course, assuming you use SPI0 and SPI1.

As an aside, I recommend your choice of hardware implementation as a physically separate SPI interconnect if you want the best analogue performance as any noise on the SPI lines - when updating the display, for instance - will inject some noise into the accelerometer unless you synchronously run the display interface outside of times when the accelerometer (or other SPI ADC or AFE) is being clocked