I'm new to Arduino but part of my career was microcontroller system build and programming, plus some c programming. I recently bought an Arduino R3 clone, and did the blink test. Then I bought an mcufriend ili9488 'TFT 3.6 inch LCD Display Touch Screen Module Arduino UNO R3 Board Plug and Play' on ebay for $7.31 (it actually says 3.5 inch on the board, but I'm not worrying about it). It plugged right into the Arduino (pins used shown in attachment), so you don't need a voltage converter shield, or any wiring at all. I followed the directions available here and elsewhere to get it running, and I was very pleasantly surprised when it did the GLUE_Demo_480x320 perfectly. However, none of the 'touch' tests would compile. Errors indicated a lack of the touchscreen library, so I got touchscreen.zip from GitHub. Then the examples compiled, and they seem to run properly - except that the touch doesn't work. I realize it might be a faulty LCD, but I've seen suggestions that the touch functionality might need some of the same or different pins as the display, and I'm wondering if maybe the libraries or information aren't quite up to date with this particular configuration. Has anyone out there gotten the touch to work on this 'Plug and Play' type of LCD on an Uno/R3? If you just want to offer an uninformed opinion (like 'mcufriend boards are crap'), please don't.
Please be accurate with your descriptions. The JPEG shows a 3.6" shield that looks very much like a 400x240 ILI9327 display.
- Does your shield match that photo?
- What controller is reported by the MCUFRIEND_kbv library examples?
Measure the resistance of your Touch screen.
Identify X, Y or whether the screen is broken.
David.
The same display and the same problem...
"Measure the resistance of your Touch screen."
Whense measured?
-Pasi
The MCUFRIEND_kbv library can be installed via the Library Manager.
It contains an example called diagnose_touchpins.ino
It will also tell you the controller ID
David.
"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
Testing : (A2, D6) = 23"
This ok? What should I do?
No, it has only found one set of Touch pins. Probably XM, XP.
Since you don't appear to have a YP, YM pair, I suggest that your Shield will not be any good for Touch.
You can try A1 and D7 with a DMM. I bet that your glass is cracked or the Touch ribbon is not soldered properly.
Which board size, what controller, which Ebay vendor?
If it is broken, the Ebay vendor should refund your money.
Perhaps they will start protecting their packages properly.
David.
That is just a typical mendacious Ebay vendor. It shows photos of a 240x400 3.6" pcb and then describes it as 320x480 with ILI9488.
At least all the photos look like 240x400.
Some vendors mix photos of 240x400 with photos of 320x480 to be even more confusing.
You must examine your shield with your own eyes.
- does it say 3.6" or 3.5" ?
- does the MCUFRIEND_kbv library identify the controller? What is the ID?
- is the glass cracked?
If your DMM can read 500 ohms between A1 pin and D7 pin, the Touch panel is ok.
However my diagnostic sketch shows this is unlikely.
Ask for your money back. They have not supplied a "Touch" screen. You still get to keep a working non-Touch screen. Buy a replacement screen and keep your fingers crossed that it does not arrive broken.
David.
- measured 3.46"
- 0x7796
- Now I have found, at the corner fracture.
Ah-ha. You have a Sitronix ST7796 with a 320x480 panel.
Ask for a refund because you have a broken Touch Panel.
And I bet that it says 3.5" on the pcb. Note that screens are measured on the diagonal of the visible area.
David.