PiDuino Library

SPI.begin(driverName)

Initialize SPI as Master and opens the specified device driver name port.

Parameters

driverName - SPI device driver name port. (e.g. “/dev/spidev0.0”)

Returns

None

Example

#include <Arduino.h>
#include <SPI.h>

// Sends "Hello World!" byte by byte through SPI

SPISettings settingsA(2000000, MSBFIRST, SPI_MODE1); 

void setup() {
	SPI.begin("/dev/spidev0.0");
}

void loop() {
	char c;
	char ret;

	SPI.beginTransaction(settingsA);
	for (const char * p = "Hello World!\n" ; c = *p; p++) {
		ret = SPI.transfer(c);
		printf("%c", ret);
	}
	printf("\n");
	SPI.endTransaction();

	delay(1000);
}

Example 2

#include <Arduino.h>
#include <SPI.h>

// Sends "Hello World!" byte by byte through SPI

void setup() {
	SPI.begin("/dev/spidev0.0");
	SPI.setClockDivider(2000000);
	SPI.setBitOrder(MSBFIRST);
	SPI.setDataMode(SPI_MODE1);
}

void loop() {
	char c;
	char ret;

	SPI.beginTransaction(settingsA);
	for (const char * p = "Hello World!\n" ; c = *p; p++) {
		ret = SPI.transfer(c);
		printf("%c", ret);
	}
	printf("\n");
	SPI.endTransaction();

	delay(1000);
}

Notes

• You can use the separate functions (SPI.setClockDivider(), SPI.setBitOrder(), SPI.setDataMode()) to configure the SPI or use SPISettings which is the same.

• Available clock speeds.
  You can put directly the clock speed or use the constants below which are the clock speeds for a 16 MHz Arduino microcontroller. Default is SPI_CLOCK_DIV4 or 4000000 (4 MHz).

• Available bit Orders LSBFIRST (Least Significant Bite First) and MSBFIRST (Most Significant Bite First). Default is MSBFIRST.

• Available SPI modes below. Default is SPI_MODE0.

• The Chip Select (CS) Pin is enabled by default as Active_Low but in the next library release it will be disabled and EXTRA functions will be added to enable or configure it.

• SPI default device driver is “” (empty) meaning that it will search for any existent SPI device driver. if you want to change the default device driver change the SPI_DRIVER_NAME constant as the example below.

#include <Arduino.h>
#include <SPI.h>

void setup() {
        strcpy(SPI_DRIVER_NAME, "/dev/spidev1.0");
        SPI.begin(); // Will try open device driver "/dev/spidev1.0"
}

void loop() {
        ...
}