A13 - LCD7

[David Goadby]

Since the topic is currently locked can I assume that someone is looking into this?

The LCD seems to be useless under Linux at the moment unless we carry out a hardware fix. I assume the problem is the LCD is driven by the PWM to control the brightness. For now, I would be happy for a kludge just to turn it on.

[olimex]

I have no idea why the author locked this topic but you should not drive PWMs at all
all you need is to use the LCD enable GPIO and to set it 1/0 to enable/disable the backlight
no need for hardware fixes!

[David Goadby]

Thanks for reply. I will try it later today. Is the I/O labelled something obvious like LCD_ENABLE or do I just use the pin number?

[olimex]

the signal is PB2 or PIN 6 / PWM0 which is used in Android to adjust the backlight with PWM frequency
under Linux you can keep it always on for maximum brightness

[marcellus.pereira]

I locked the topic because it is solved. The instructions are there.

[David Goadby]

Well, I agree that a hardware change does offer one solution to the problem. However not all of A13 users will be able to do this and some would rather not modify the A13 for fear of damaging it.

The real solution is a software one relating to the PB2/PWM pin.

If an acceptable software solution for Linux proves too difficult then maybe Olimex will add a user accessible jumper on the A13 board for this. If fact, the best place for this is probably the LCD board itself.

[cypher]

Hi all,

if you just want to "switch" the backlight on you can change the following parameter in the script.bin file

lcd_pwm_pol -> change to "0" if your actual value is "1" or vice versa.

I have tried this parameter change on a debian system and it works.

Marc

[David Goadby]

Thanks for that. It worked perfectly!

[cypher]

Hi David,

just ashort question:

Is text on your display in the upper left corner? On my display is a gap between the display frame and the beginning of the text. It is about 3 cm. The whole display is shifted to the right side.

Greetings

Marc

[David Goadby]

Hi Marc,

No, the display is exactly right.

If you just turned on the LCD backlight using the hardware mod or setting PB2 then you might have the wrong display setting. When using the LCD the display resolution is 640 X 480 instead of the standard 800 X 600.

If the VGA output looks good and the LCD bad then you probably do have the wrong version of script.bin file loaded. Note that when using LCD mode some VGA monitors struggle to show the text well and some text may be lost on the left hand side. It seems we cannot have both together. It's the same for the Android software too.

If you cannot find a copy of script.bin for LCD then I can send you a copy.

[lorenzo]

Hi David,

but isn't the resolution supposed to be 800x480. I tried with 800x480 but I have the same problem as Marc, I have a gap on the left side.

Can you send me a copy of your script.bin configuration?

Thank you.
Best.
Lorenzo

[cypher]

Hi David,

many thanks for the file. Unfortunately it didn't works out of the box. I changed some entries and now it works like a charm.

I directly installed XFCE4 and it looks very pretty on the lcd.

Best regards

Marc

[cypher]

Hi lorenzo,

you can download my script.bin here:

http://dl.dropbox.com/u/22490369/script.bin

I hope it works

Marc

[David Goadby]

Hi Marc,

I am curious what the problem was with my file and what you changed.

I will try XFCE4 too a little later. Is it in the standard repository?

Regards

David

[cypher]

Hi David,

I can you send the differences today in the evening after work. But as far i can remember there were some timing parameter.

Best regards

Marc