Hi,
I am trying to read two bytes of data from a board(slave) using BBB(master)
through i2c interface.
I connected my board's SDA and SCL lines to P9_18 and P9_17 of BBB
respectively.
My code is
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
int main()
{
int fd,i;
int addr = 0x43;
char buffer[10] = {0};
fd = open("/dev/i2c-1", O_RDWR); // opening i2c-1 file. returns a file
descriptor used by read
if(fd < 0)
{
printf("i2c failed to open\n");
}
if(ioctl(fd, I2C_SLAVE, addr) < 0)
printf("failed to acquire bus\n");
if(read(fd,buffer,2) != 2) //reading 2 bytes of data
{
printf("i2c read failed\n");
}
else
{
for(i=0;i<2;i++)
printf("the data is %d \n",buffer[i]);
}
return 0;
}
I got output --- "i2c read failed"
What is the problem in my code? Or any problem in hardware? When I checked
the following command, I got output like
root@beaglebone:~# i2cdetect -l
i2c-0 i2c OMAP I2C adapter I2C adapter
i2c-1 i2c OMAP I2C adapter I2C adapter
root@beaglebone:~# ls -l /sys/bus/i2c/devices/i2c-*
lrwxrwxrwx 1 root root 0 Jan 1 2000 /sys/bus/i2c/devices/i2c-0 ->
../../../devices/ocp.3/44e0b000.i2c/i2c-0
lrwxrwxrwx 1 root root 0 Jan 1 2000 /sys/bus/i2c/devices/i2c-1 ->
../../../devices/ocp.3/4819c000.i2c/i2c-1
Can anyone find problem? Please reply.
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