Problem LCD 10' & A20-SOM204-EVB

[Arn]

Hello,

I started with A20-SOM204-EVB with SDCard Ubunto 18.04.1 and a LCD-OLinuXino-10CTS.
With a serialSniffer I can connect to A20, login correctly, ... but the LCD is always black.

I has the A20 & LCD at 5 Volts.

I read this at the wiki:
https://www.olimex.com/wiki/A20-OLinuXino-MICRO#How_to_change_HDMI.2C_VGA_and_LCD_resolutions_in_the_official_Debian_image.3F
but my root directory is empty.

Also I read that I have stop the u-boot and there I can try to detect the LCD and change the configuration. But I don't see the u-boot.

Someone know something to try.

Thanks.

[akka]

Hi!

I have had the same problem with MICRO + 10" LCD. The solution was the previous image I think the 5.56 Armbian Ubuntu version. But with another 10" LCD (ordered the same time) was not worked with the same version, only a newer one.
These are annoying things...

[Arn]

Thanks for the reply,

It seems the problem is the LCD's version.

Is there any way to detect the version? or update the LCD's firmware?

[LubOlimex]

Hello,

LCD-OLinuXino-10CTS should be automatically recognized by the board and proper resolution should be launched. So first consider these three points:

1. Make sure that the hardware connections between the board and the display are alright.

2. Make sure you are using latest Olimex-made Ubuntu image. It might require re-writing the card. The image can be found here: ftp://staging.olimex.com/Allwinner_Images/A20-OLinuXino/1.latest_mainline_images/bionic/images/

3. You might have touchscreen problems if you didn't specify that you are going to use A20-OLinuXino-MICRO with a capacitive touchscreen. Using capacitive touchscreen with the A20 boards requires a slight hardware modification.

> or update the LCD's firmware?

The LCD has no firmware.

If there are problems with the automatic recognition, in the latest images, you are be able to stop u-boot in order to configure different video output settings manually. This might not be possible over every medium that is used for connecting to the board. Some interfaces are launched after the kernel starts, and it is no longer possible to interrupt the boot. That is why it is recommended to use the direct serial connection between the PC and the board, via USB-serial adapter (attached to three debug pins).

> Also I read that I have stop the u-boot and there I can try to detect the LCD and change the configuration. But I don't see the u-boot.

How do you connect to the board?

Best regards,
Lub/OLIMEX

[Arn]

Thanks,
Like you say the serial was wrong.

I have the board connected by microUSB to PC, I switch to debug pins and selected the 10CTS monitor in the list.

Now the LCD show the desktop but the touch don't work.

Where I can find the "slight hardware modification" ?

I'm reading the OLinuXino-LCD-Selection-Guide.pdf and I see:
- In A20-Olinuximo-Micro I have to switch RM1 to RM2
- In A20-Olinuximo-Lime I have to switch RM10 to RM9

But what I have to switch in A20-SOM204 ?

[LubOlimex]

RM3 should go to RM4 - these are located on the A20-SOM204 board.

[Arn]

Ok, perfect
All works fine now.