SPI master on nRF5122

Question

I'm using nRF51822 SoC and I have a LIS3DSH accelerometer connected to the ship via SPI bus . I used the SPI master example . So i used the switch_state() function then took the rx_data and tx_data . But when debugging the Keil logic analyzer don't show me any modifacation . Does that mean that i didn't configure the spi right ? IN addiction to that , I have in the data sheet of the LIS3DSH the addressees of the registers containing the X ,Y and Z values , what shall i do to extract them ?

Stian Røed Hafskjold · Accepted Answer

(Since you didn't mention, I assume you are using SDK 8 and the nRF51 DK) 
 Did you have a look at the documentation for that example? developer.nordicsemi.com/.../a00046.html. 
 It says you need to connect the MOSI and MISO pins of both SPI 0 and SPI 1. That is: 
 pin 1 -> pin 3 
 pin 12 -> pin 14 
 Now LED 2 should blink. And you should see activity on one of the two SPI interfaces every second. 
 The read sequence of the LIS3DSH is described in the datasheet in section 6.2.1. First you need to set the RW-bit high, then write out the address of the X, Y or Z register you want to read. Then read the SDO line. 
 The code would look something like this: 
 int main(void)
{
 bsp_configuration();
	
	uint8_t OUT_X_L_addr = 0x28; // The address of the register you want to write
	uint8_t tx_data[2] = {0x00, 0x00}; // Transmit register
	uint8_t rx_data[2] = {0x00, 0x00}; // Receive register

 for (;; ){
 spi_master_init(SPI_MASTER_0, spi_master_0_event_handler, false);
 tx_data[0] = (0x80 | OUT_X_L_addr); //Add the RW bit to the address.
 spi_master_send_recv(SPI_MASTER_0, tx_data, 2, rx_data, 2);

 // Now rx_data[1] should contain the OUT_X_L value;
 }
}
 
 EDIT: 
 Here is a step by step guide to include spi_master to a BLE project (SDK 7.2): 
 
 
 Add spi_master.c to your project 
 
 
 #include "spi_master.h" in main.c 
 
 
 #include "app_util_platform.h" in main.c 
 
 
 add ..\..\..\..\..\..\components\drivers_nrf\spi_master to your include path in the C/C++ fan in options 
 
 
 Add the init function to main.c: 
 static void spi_master_init(spi_master_hw_instance_t spi_master_instance,
 spi_master_event_handler_t spi_master_event_handler,
 const bool lsb)
 {
 uint32_t err_code = NRF_SUCCESS;
 spi_master_config_t spi_config = SPI_MASTER_INIT_DEFAULT;
 spi_config.SPI_Pin_SCK = SPIM0_SCK_PIN;
 spi_config.SPI_Pin_MISO = SPIM0_MISO_PIN;
 spi_config.SPI_Pin_MOSI = SPIM0_MOSI_PIN;
 spi_config.SPI_Pin_SS = SPIM0_SS_PIN;
 spi_config.SPI_CONFIG_ORDER = (lsb ? SPI_CONFIG_ORDER_LsbFirst : SPI_CONFIG_ORDER_MsbFirst);

 err_code = spi_master_open(spi_master_instance, &spi_config);
 APP_ERROR_CHECK(err_code);

 // Register event handler for SPI master.
 spi_master_evt_handler_reg(spi_master_instance, spi_master_event_handler);
 }
 
 
 
 Add the event handler to main.c: 
 void spi_master_0_event_handler(spi_master_evt_t spi_master_evt){}
 
 
 
 Add SPI_MASTER_0_ENABLE to the 'Define' field in the C/C++ fan under options. 
 
 
 To test, add this to your main(void) function after ble_stack_init() : 
 uint8_t OUT_X_L_addr = 0x28; // The address of the register you want to write
 uint8_t tx_data[2] = {0x00, 0x00}; // Transmit register
 uint8_t rx_data[2] = {0x00, 0x00}; // Receive register
 spi_master_init(SPI_MASTER_0, spi_master_0_event_handler, false);
 for (;; )
 {
 tx_data[0] = (0x80 | OUT_X_L_addr); //Add the RW bit to the address.
 spi_master_send_recv(SPI_MASTER_0, tx_data, 2, rx_data, 2);
 power_manage();
 }
 
 
 
 Here is my main.c file. It is based on the ble_app_beacon example. It is important that you initialize the spi after the softdevice (ble_stack_init()). Have a look at the file and see if you have done things any differently.

SPI master on nRF5122

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