Posts by grasbon

grasbon · Mar 21st 2012

Thanks for your responses,
the problem is solved.
You were right, the voltage of the LED-background (it was a LED no CCFL), is nearly at 0V (150mV), when the PWM-value is 0. This residual voltage was sufficient to let the background LED glow at (maybe) 15-20%.

grasbon · Mar 20th 2012

Hello,

I use the recommended function from the examples-folder to
adjust the brightness of the LCD backlight:

Code

int fd = open("/sys/devices/platform/s3c24xx-pwm.1/pwm-backlight.0/"
"backlight:pwm-backlight/brightness", O_WRONLY);
write(fd,"200",3);
fsync(fd);
printf("set brightness to 200\n");
sleep(5);
write(fd,"0",1);
fsync(fd);
printf("set brightness to 0\n");
sleep(5);
close(fd);

Display More

But setting the value to zero keeps the brightness at nearly 50%. Why isn't
it possible to set the duty cycle of the PWM according to brightness-value
(0 to 0% .. 255 to 100%), what means a value of 0 will shut off the backlight?

Kind regards,
Reimar

Posts by grasbon

LCD brightness minimum level 50%?

LCD brightness minimum level 50%?