SPI for NanoPi - Revision history

Admin at 14:03, 1 March 2020

2020-03-01T14:03:31Z

Admin at 14:02, 1 March 2020

2020-03-01T14:02:38Z

Admin at 13:52, 1 March 2020

2020-03-01T13:52:48Z

Admin: /* SPI for NanoPi */

2020-03-01T13:52:35Z

SPI for NanoPi

Admin: Created page with "== SPI for NanoPi == #include #include #include #include #include #include #include #i..."

2020-03-01T13:52:16Z

Created page with "== SPI for NanoPi == #include <stdint.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <getopt.h> #include <fcntl.h> #include <sys/ioctl.h> #i..."

New page

== SPI for NanoPi ==

#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

static const char *device = "/dev/spidev1.0"; // /dev/spidev0.0 or /dev/spidev0.1
static uint8_t mode = 0; // SPI_MODE_0 (see text)
static uint8_t bits = 8; // 8 or 9
static uint32_t speed = 1000000; // Clock frequency [Hz]
static uint16_t delay = 0; // Time between end of data and CS de-assert

// Exit and print error code
static void exit_on_error (const char *s) {
perror(s);
abort();
}

int main(int argc, char *argv[]) {
int fd;
int Buffer_size;
uint8_t tx[] = {0x01, 0x02, 0x04, 0x08, 0x55, 0x00, 0xAA, 0xFF, }; // Data to send
Buffer_size = sizeof(tx); // Size of TX (and RX) buffer
uint8_t rx[sizeof(tx)] = {0, }; // RX buffer

struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long)tx,
.rx_buf = (unsigned long)rx,
.len = Buffer_size,
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
.cs_change = 0,
};

// Open SPI device
if ((fd = open(device, O_RDWR)) < 0) exit_on_error ("Can't open SPI device");

// Set SPI mode
if (ioctl(fd, SPI_IOC_WR_MODE, &mode) == -1) exit_on_error ("Can't set SPI mode");

// Read and write data (full duplex)
if (ioctl(fd, SPI_IOC_MESSAGE(1), &tr) < 1) exit_on_error ("Can't send SPI message");

printf ("Data from SPI Rx buffer: ");
for (int i = 0; i < Buffer_size; i++) printf("%.2X ", rx[i]);
printf ("\n");

close(fd);
return (0);
}

← Older revision		Revision as of 14:03, 1 March 2020
Line 66:		Line 66:
	return (0);		return (0);
	}		}
		+
		+	To test, ececute the command with and without the MISO/MOSI in loopback.

← Older revision		Revision as of 13:52, 1 March 2020
Line 1:		Line 1:
	== SPI for NanoPi ==		== SPI for NanoPi ==
		+

@@ Line 1: / Line 1: @@
 == SPI for NanoPi ==
   #include <stdint.h>
   #include <unistd.h>

@@ Line 49: / Line 49: @@
       // Read and write data (full duplex)
       if (ioctl(fd, SPI_IOC_MESSAGE(1), &tr) < 1) exit_on_error ("Can't send SPI message");
-−
       printf ("Data from SPI Rx buffer: ");
       for (int i = 0; i < Buffer_size; i++) printf("%.2X ", rx[i]);
       printf ("\n");
-−
       close(fd);
       return (0);
+  }