implement 2 hardware SPI

RE: implement 2 hardware SPI

hmolesworth — Wed, 28 Mar 2018 19:15:58 GMT

I notice I am using pull-up on MISO, not sure if that is relevant. Did you get your setup working?

// > P0.07 ACC-INT1    CNF: 0x00000000 [Sense: Off] [Drive: Normal] [Pull: None] [Input: Connected ] [Dir: Input ] (now 0) (no map)
// > P0.09 ACC-MISO    CNF: 0x0000000C [Sense: Off] [Drive: Normal] [Pull: P-Up] [Input: Connected ] [Dir: Input ] (now 1) (SPI2 MISO)
// > P0.17 ACC-SCK     CNF: 0x00000003 [Sense: Off] [Drive: Normal] [Pull: None] [Input: Disconnect] [Dir: Output] (now 0) (SPI2 SCK)
// > P0.19 ACC-MOSI    CNF: 0x00000003 [Sense: Off] [Drive: Normal] [Pull: None] [Input: Disconnect] [Dir: Output] (now 0) (SPI2 MOSI)
// > P0.20 ACC-CS      CNF: 0x00000003 [Sense: Off] [Drive: Normal] [Pull: None] [Input: Disconnect] [Dir: Output] (now 0) (no map)

RE: implement 2 hardware SPI

Dave_couling — Sun, 25 Mar 2018 21:00:10 GMT

As Aryan mentioned you'd need to implement a method of selecting/deselecting the chip select pin on each of your SPI ICs. I found the easier method for this is to writer a wrapper class around nrf_spi_drv where you pass the chip select pins in at initialization.

RE: implement 2 hardware SPI

hmolesworth — Sun, 25 Mar 2018 19:44:47 GMT

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

RE: implement 2 hardware SPI

yuval — Sun, 25 Mar 2018 07:12:35 GMT

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 ?

RE: implement 2 hardware SPI

Susheel Nuguru — Thu, 22 Mar 2018 13:27:57 GMT

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