Hi,
I'm trying to use an Adafruit Oled display directly under Yocto (1.0.0.7 compiled with dev tools).
I know that I plugged the screen correctly cause I was able to run the adafruit sketche sample (with some modifications) through the arduino IDE.
I guess I'm using the standard method under Yocto:
modprobe i2c-dev
chmod 666 /dev/i2c*
Then in my C file:
#define addr 0x3D
void send_command(int i2c, unsigned char command){
unsigned char buf[10]; unsigned char control = 0x00; buf[0] = control; buf[1] = command; buf[0] = control; if (i2c_smbus_write_byte(i2c,control) == -1) { printf("Failed to write to the i2c control.\n"); } usleep(10000); buf[0] = command; if (i2c_smbus_write_byte(i2c,command) == -1) { printf("Failed to write to the i2c command.\n"); perror("write data fail\n"); } usleep(10000);
}
int main(int argc, char* argv[]){
printf("Begin of program...\n"); int i2c, reset; char *filename = "/dev/i2c-0"; if ((i2c = open(filename, O_RDWR)) < 0) { /* ERROR HANDLING: you can check errno to see what went wrong */ perror("Failed to open the i2c bus"); exit(1); } usleep(10000); if (ioctl(i2c, I2C_SLAVE_FORCE, addr) < 0) { printf("Failed to acquire bus access and/or talk to slave.\n"); exit(1); } usleep(10000); send_command(i2c, 0xae); return 0;
}
Now, when I run this code, I end up with:
Failed to write to the i2c control.
Failed to write to the i2c command.
write data fail
: Remote I/O error
I also downloaded i2c tools and I can't use i2cset or i2cget:
galileo# i2cget -y 0 0x3D
Error: Read failed
The address (0x3D) seems fine cause it's the same as the one used in the adafruit arduino scketche and the :
(ioctl(i2c, I2C_SLAVE_FORCE, addr)
doesn't fail.
So have you ever seen this problem ? I hope it doesn't come from the i2c driver...
Thanks.
Cedric