[SPI] Using Multiple Slaves

newbie · December 14, 2020

I can run spi with the code below. But I have to communicate with too many slaves on the same line. I will connect all the devices with the same MISO - MOSI - SCLK line.

static void transfer(int fd)
{

	//n.SLAVE CS LOW
	
	int ret;
	uint8_t tx[] = {
		0xAD, 0x03
	};
	uint8_t rx[2] = {0, };
	struct spi_ioc_transfer tr = {
		.tx_buf = (unsigned long)tx,
		.rx_buf = (unsigned long)rx,
		.len = 2,
		.delay_usecs = delay,
		.speed_hz = speed,
		.bits_per_word = bits,
	};

	ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
	if (ret < 1)
		pabort("can't send spi message");

	//n.SLAVE CS HIGH

	puts("");
}