Using Touch panel

FTDI/Bridgetek EVE2 & EVE3 & EVE4 SPI TFT Series by Matrix Orbital

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rascalito
LCD!
Posts: 10
Joined: Sat Apr 18, 2020 11:22 pm

Using Touch panel

Post by rascalito » Fri May 15, 2020 5:57 pm

Hello!

I would like to get touch panel events. Ideally, I would like to receive an interrupt
when the screen has been touched. I could live with polling for test, but anyway for
the moment, I can't get touch coordinates. So one problem at a time, let's start with
polling.

What I did:
I have set up the address of the touch panel chip which is a Goodix. The documentation
says that the address should be 5D.
So the first thing I did is to fill in the REG_TOUCH_CONFIG register for capacitive setup
Bit 15: 0 for capacitive.
14,13: reserved
12: ignore short circuit. I suppose it's for resistive.
Bit11: enable low power mode. Not crucial for test, I will leave it as 0.
10~4 is the I2C address, 5D
Bit 3: vendor. I tried both. Is Goodix a FocalTech or AzoTech device?
Bit2: suppress 300 ms startup. Leave as 0.
Bits 1 and 0, same.

Summary:
Bits 15 to 12 = 0
Bit 11 = 0
Bits 10~4 = 5D
Bit 3 only may have an influence.
Therefore the possible codes are 0x05D8 or 0x05D0

As for the touch mode, there are only 2 bits, apparently. I tried 10 (frame mode) and 11
(continuous mode), but without success so fare.

After setting these 2 registers, I access the coordinate registers, but they are always
at 0, touch or not.

Am I missing something?

R

Raquel
Matrix Orbital
Matrix Orbital
Posts: 728
Joined: Thu Aug 19, 2004 3:37 pm
Location: MO Office

Re: Using Touch panel

Post by Raquel » Tue May 19, 2020 10:24 am

Hello rascalito,

Can you please send a photo of your setup right now? Front and back of the display please?
I just want to check connections on the board.

Thank you,
Raquel
Raquel Malinis
Design and Development
Matrix Orbital

rascalito
LCD!
Posts: 10
Joined: Sat Apr 18, 2020 11:22 pm

Re: Using Touch panel

Post by rascalito » Tue May 19, 2020 5:08 pm

Hello Rachel!

Thanks for your reply.
Sorry, but I don't understand what the picture will change. Especially the front picture,
which shows the reflection of my face when I took the picture.
Here is the setup and a closeup of my setup.
IMG_3877.jpeg
IMG_3877.jpeg (48.19 KiB) Viewed 55 times
IMG_3878.jpeg
IMG_3878.jpeg (68.1 KiB) Viewed 55 times
The board is not the final one, but it's working, I get images that you can see in my previous
messages (therefore I can access the FT813 registers, and I should be able to configure the
touch panel as well). But all what I can read in the touch register is 0. The touch panel chip
is a Goodix.

Thanks,

R.

Raquel
Matrix Orbital
Matrix Orbital
Posts: 728
Joined: Thu Aug 19, 2004 3:37 pm
Location: MO Office

Re: Using Touch panel

Post by Raquel » Wed May 20, 2020 1:59 pm

Thanks for the images. I just needed to see the connection of the touch panel, and it looks good.

Have you checked out our demo code: https://github.com/MatrixOrbital/Basic-EVE-Demo
It has GoodIX touch configuration in there, particularly for EVE2 you might want to check.

Best Regards,
Raquel
Raquel Malinis
Design and Development
Matrix Orbital

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