TFT LCD (Diagnose Touch Pins)

Using Arduino Displays
1

Hello everyone,

I'm using Arduino Uno with TFT LCD. the graphical test works great. But, when I upload the "Diagnose Touch pins" from MCUFRIEND library or the "Touchscreen calibration" from the same library, I get the following error.

please note that I have changed the screen and both of them displayed the same error.

Does anyone have any idea??

looking forward to your response

1.jpg

2

Is English your native language ?

BROKEN means that the Touchscreen is not present, the glass is cracked or the 4-way ribbon from the Touch panel is not connected.

My "diagnosis" is not perfect. You can measure the resistance with a DMM if you do not believe my diagnosis.

David.

3

I know the meaning of Broken sir :sweat_smile:

But, I was asking because there are no cracks and I've already tried it on more than one new TFT screen and it gave me the same result.

Anyway, thank you for your response :slight_smile:

4

Post a photo of the front of your screen.

Touch Panels have a "gold" line around the perimeter of the glass and a 4-way ribbon that is often at the bottom left hand corner of the screen.
There is normally a part number for the Touch Panel at the bottom right.
There are sometimes icons for house, book, letter, camera, ... at the bottom of the Touch Panel.

I have a shield with only Y-Touch. The X-Touch is broken. I have several 3.5 inch screens with cracked glass. They register as "BROKEN" too.

David.

5

Please find the requested pictures,

FullSizeRender[1].jpg

FullSizeRender.jpg
FullSizeRender.jpg1247×2131 398 KB

6

You have a Blue Mcufriend shield with a Touch Panel.

I asked for a photo of the screen side. You have provided the pcb side. And an end view of the Touch ribbon.

I would expect the diiagnosis to detect the XP, XM, YP, YM pins. Normally on A1, A2, 7, 6. Sometimes 8, 9.

You can measure the resistance with a DMM if you don't want me to see the glass screen.

David..

7

I apologize because I thought that I have attached all the photos including the screen glass.

Please find the remaining pictures,

FullSizeRender (1).jpg
FullSizeRender (1).jpg3373×2666 1.27 MB

8

Thanks. There is a Touch Panel. The glass is not cracked.

Do you own a DMM ?

Unplug the shield. Measure the resistance between A2 (LCD_RS) and 6, 7, 8, 9
Repeat for A1 pin and A3 pin.

It is unlikely that other pins are used.
A valid Touch value would be between 300 and 600 ohms.
Write down which pairs of pins have resistance.

David.