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Topic: 2.4 inch tft LCD ili9340 touch problem (Read 1 time) previous topic - next topic

marteen1337

hi !

my 2.4" lcd shield from mcufriend have problem with touch calibration:
the "TouchScreen_Calibr_native" code reports the Broken Touch !
the serial monitor report of "Touch_shield_new" is:

Most Touch Screens use pins 6, 7, A1, A2
But they can be in ANY order
e.g. right to left or bottom to top
or wrong direction
Edit name and calibration statements

Please Calibrate.
ID=0x9340
Screen is 240x320
Calibration is:
LEFT = 907 RT  = 136
TOP  = 942 BOT = 139
Wiring is always PORTRAIT
YP=15 XM=16
YM=7 XP=6

===============================

when testing with "Adafruit_TouchScreen-master" library there is a response from bottom of touch and the Pressure value changes. but the top of the touch need more pressure to change the pressure value.
the serial monitor report of "touchscreendemoshield.ino" is:
when not touched ---> pressure=100~117
when touched ---> pressure=420~560

===============================

how can i fix this? its possible pin of the touch is different: XP,XM,YP,YM

why YP,XM not A1,A2 in serial report?


thank you !!!

david_prentice

#1
Oct 13, 2019, 08:41 pm Last Edit: Oct 13, 2019, 08:44 pm by david_prentice
If the Calibration sketch says "Broken TouchScreen" it means that either there is no Touch Panel or the glass is cracked.

If you don't believe the sketch,   read the resistance with a DMM.

There is an updated Calibration sketch with a link in this message

There is no point in calibrating a missing or broken TouchScreen.
If you have a good panel but bad calibration,  please copy-paste from the Serial Terminal to your message

David.

marteen1337

thank you !

im testing with multimeter when shiled not connected to uno the resistance between XP,XM is infinite !!!
is it my test true? or must be turn on the shield and make test?

and this is the serial message from updated sketch:

TouchScreen.h GFX Calibration
Making all control and bus pins INPUT_PULLUP
Typical 30k Analog pullup with corresponding pin
would read low when digital is written LOW
e.g. reads ~25 for 300R X direction
e.g. reads ~30 for 500R Y direction

MISSING TOUCHSCREEN
ID = 0x9340

david_prentice

Look at the front of your shield.
A Touch Panel has a gold stripe around the outside with four gold strips at the bottom right of the screen.
A 4 way ribbon joins the gold strips.

Compare your shield with photos of genuine Touch Shields.
Or post a photo.

David,

marteen1337

okay !

i check the lines aroud the lcd at the middle-top of the screen has a space(like 45 degree cut) and also there is a space at the bottom of lcd. is this cutting or space okay?

4 pin connector seems to be okay and firmly connected to pcd !

now im sending some photo !!!

tnks !

david_prentice

Your photo shows the top of the screen.   Any Touch Panel electrodes will be at the bottom of the screen.

Yes,  it "looks" like the top of a Touch Panel.   It also looks as if the electrode has a diagonal cut near the pushbutton K1.

Please post a photo of the whole screen.

David.

marteen1337

and i this is the bottom image:

marteen1337

and total screen image:

forum cant allow me to send post repeatedly! (im new member) :(

david_prentice

#8
Oct 14, 2019, 01:50 pm Last Edit: Oct 14, 2019, 01:53 pm by david_prentice
You definitely have a Touch Panel.   Ribbon at bottom left.   Icons are a pretty big clue !!!

I have always assumed that the printed gold electrodes will be on the underside of the glass.
Is your diagonal cut on the surface of the glass?
You have a second diagonal cut near the "Home" icon.    The Touch Panel was deliberately damaged.

If your Shield was advertised as a "Touch" display,   ask the shop for your money back.
The Touch does not work.

David.

marteen1337

yes shield have a touch in the shopping website !

these not cut like something with knif, just two spaces !!! yes on the surface

the glass havnt any cut or crack- i look it with flashlight, edge of glass is normal and not seem to be broken !

testing LCD-D7 and LCD-WR pins dont show any resistance(ohm)!!!
and also for D6 and RS pins
but when i press the screen multimeter shows ~3Mega ohm

i think buy another because the seller wont give back modules !


marteen1337

if i want to buy the new touch lcd, that one should havnt any spaces around the lcd ? is it true?


---> thank you for helping <---

david_prentice

#11
Oct 14, 2019, 03:07 pm Last Edit: Oct 14, 2019, 03:10 pm by david_prentice
A regular 2.4 inch Mufriend shield will look like your photos but without the diagonal cuts.

Any Ebay vendor will refund 100% immediately.   You have received damaged item.    They will not ask you to return the item.

Any local shop will replace the item with good shield.

In theory AliExpress require you to return the item.
In practice I doubt if they will make a fuss.

Both Ebay and AliExpress can resolve "disputes".
Both Ebay and AliExpress accept and publish buyer feedback.

No vendor wants to see this sort of complaint.
You have photographic proof that the items were supplied as damaged goods.
This is very different to an item that was "damaged in the mail" or damaged by the user.

It is very important that buyers report problems to Ebay, AliExpress, web shop.

If you have trouble with Ebay, Ali, local shop, ...  report the shop on this Forum e.g. link to the Ebay sale or shop website.

David.

marteen1337

thanks !

im in iran and they say the customers only have 24~48 hours for testing any modules and after that the seller
cant give back or payback money !

but im calling shopping site admin for this


david_prentice

I am sure that Iranian shops will give you 100% service.

If they sold it as a Touch Screen,  they should either replace or refund.

David.

marteen1337

#14
Oct 15, 2019, 07:45 am Last Edit: Oct 15, 2019, 08:01 am by marteen1337 Reason: make two post in one post
i forget to say, at first time i program this sketch to uno and test lcd !!!
is it possible this program change the lcd registers in chip ili9340 ?

i upload my first test code:


==============

in this picture there is space aroud the lcd:

https://circuitdigest.com/microcontroller-projects/arduino-touch-screen-calculator-tft-lcd-project-code


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