rpi-blink.c

#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/spi/spidev.h>
#include <string.h>

static const char *device = "/dev/spidev0.0";
static uint32_t speed = 100000;

int main(int argc, char *argv[])
{
  int ret = 0;
  int fd;

  fd = open(device, O_WRONLY);

  ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
  if (ret == -1)
    printf("ERRR SETTING SPEED %i\n", ret);
  
  char bytes0[10];
  memset(bytes0, 0, 10);

  char bytes1[10] = {0b11001111, 0b10110011, 0b11101101, 0b11011011, 0b1101110, 0b11011011, 0b10110101, 0b10101101, 0b01101011, 0b10101110};
  
  while(1) {
    write(fd, bytes1, 10);
    sleep(1);
    write(fd, bytes0, 10);
    sleep(1);
  }

  close(fd);

  return ret;
}