2.6 Foundation Drivers: SPI Master - Loopback

/**
\file
\brief This file contains sample source codes to demonstrate the SPI Foundation Services APIs.

For this example application to work the following needs to be done:
    1. Configure the SPI module as follows:
        - Enable SPI: ticked
        - Modes: Master
        - Interrupt driven: unticked
        - Configure other settings as desired.
        - Select TX and RX pins in Pin Manager: Grid View.
    2. Make loop back connection to MISO and MOSI or connect SPI pins to a slave
    3. If connected to a slave, assign CS pin and add the necessary calls in drive_slave_select_low() and drive_slave_select_high()
    4. Program the slave device to exchange the string "data"
    5. Call SPI_Master_test() from main()   

This example works like this:
    1. Upon reset, the application will transmit a string "data" and read the same number of bytes back.
    2. The program will then compare the received string with "data". Returns 1 to indicate a match or 0 if not.

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*/

#include <stdio.h>
#include <string.h>
#include "../drivers/spi_master.h"

static uint8_t buffer[16] = "data";

static void drive_slave_select_low(void);
static void drive_slave_select_high(void);

static void drive_slave_select_low(){
	// Control GPIO to drive SS_bar low
}

static void drive_slave_select_high(){
	// Control GPIO to drive SS_bar high
}

uint8_t SPI_Master_test(void)
{
	// Test driver, assume that the SPI MISO and MOSI pins have been looped back
	
	if(!spi_master_open(MASTER0))
		// Not able to open SPI, call fail() or optionally do something 
		// else waiting for the SPI to become free
		return 0; 
	
	drive_slave_select_low();
	SPI0_ExchangeBlock(buffer, sizeof(buffer));

    drive_slave_select_high();

    SPI0_Close();
	
	// Check that the correct data was received
	if (strncmp((char*)buffer, "data", strlen("data")))
		return 0; // ERROR: Wrong data received
	
	// If we get here, everything was OK
	return 1;
}

/**
 End of File
 */