SPI Bus - Raspberry Pi Hardware Reference - page 196

43 rc = ioctl(fd,SPI_IOC_WR_MODE,&mode);
44 if ( rc < 0 )
45 errxit("ioctl (2) setting SPI mode.");
46
47 rc = ioctl(fd,
SPI_IOC_WR_BITS_PER_WORD,
&ioc.bits_per_word);
48 if ( rc < 0 )
49 errxit("ioctl (2) setting SPI bits perword.");
50
51 rc = ioctl(fd,SPI_IOC_MESSAGE(1),&ioc);
52 if ( rc < 0 )
53 errxit("ioctl (2) for SPI I/O");
54 close(fd);
55
56 printf("rc=%d %02X %02X %02X %02X\n",
57 rc, rx[0], rx[1], rx[2], rx[3]);
58 return 0;
59 }