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Resistive Touchscreen, how does TouchGFX know about the Y1,X1,Y2,X2 connections from the screen? And how does it know a button was clicked?

Associate III

I'm setting up a custom board. I was planning to use a NewHaven resistive touch screen with RGB888 and the STM32L4S9.

I've been using the stm32F429Disc1 board to learn how to use TouchGFX with Cube IDE. I thought I'd be able to figure out how that works since it has a resistive touch screen. I don't see how the touch coordinates gets back to the MCU from the screen (physical pin out/ or what triggers the correct interrupt when a button was pressed). I also haven't figured out how to configure CubeIDE/TouchGFX so it knows about X1, Y1, X2, Y2 on the resistive touch screen.

I'm sure there are instructions and examples somewhere showing how to setup TouchGFX? Does the info get communicated from the I2C/SPI connection?

Also, any recommendations for touch screens 2.8-3.5 inch for new designs that integrate nicely with TouchGFX. I've had good luck with the New Haven LCD displays for past projects, but I'd like to know but if there is a better option for new designs?



I found the answer to part of my question. The issue was because I opened the board design files with Altium, the page with the LCD info didn't open. When I opened the PDF version it had the LCD schematic with the touch screen controller STMPE811QTR. So the UC gets the info from the I2C connection to the resistive touch screen controller.

The STMPE811QTR is no longer in production, so I'm planning to use an alternate from TI.

I'm still not finding where to set this up in STMCube? For example the I2C address settings? The touch screen controller is on I2C1 instead of I2C3 etc. Is there an interrupt that triggers getting the I2C info from the touch screen controller?


ST Employee

Hello SWood.4,

We have an article about Touch Controlers in our support website, I don't know if you'll find all the answers you're looking for but I can suggest you to have a look at it.

Otherwise, when you download STM32CubeMX, you'll get hundreds of examples of different projects and there's also maybe one example you can get inspiration from (you can find this in your computer at the path : C:\Users\YOUR_USER_NAME\STM32Cube\Repository)


ST Software Developer | TouchGFX