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Questions for touchscreen
Posted: Tue Sep 26, 2017 3:07 pm
by pietro1212
Hello to everyone.
I entroduce myself because I’m a new member of this community.
I’m pietro and I’m about to buy my first Raspberrypi, but first I would like to have your opinions.
Here is what I would like to do:
I want connect a 10 inch touchscreen with a Raspberry (7’’ touchscreen from raspberrypi.org/products is too small) and I want to use Raspbian as OS. My first question is: can I buy a common touchscreen and just find a Raspbian’s driver for the touchscreen? If yes: do you know where ca I download such a driver?
Can I use USB port for touchscreen or I have to use DSI port?
Thank you to anyone in advance!!
Re: Questions for touchscreen
Posted: Tue Sep 26, 2017 9:43 pm
by OutoftheBOTS
So do understand that a touch screen is 2 separate devices stuck together. It is a screen and a touch panel on the front of the screen. You will have to look at how the RPi ios going to talk to both the screen and the touch controller on the screen.
As you go larger screens you usually want to have a higher res so that the pixels don't become large. As you have a higher res then the RPi needs to sedn more data so the method that you use for the RPi to talk to the screen needs to fast. The DSI ribbon is fairly fast but the HDMI is the fastest of all and HDMI screens r very common.
The second problem is you need to find what coms the touch part of the screen uses. Some use usb like a mouse, some use I2C like the offical RPi 7" and some use SPI like the little XPT2046 controllers.
One of the many screens that I use has HDMI plug for image stream in and a USB plug for the touch screen to act like a mouse. This screen is totally just plug and play and I don't need to install any drivers at all because the standard RPi operating system has HDMI and mouse drivers built in.
But some of my other screens that I use I need to load driver to make them work.
Re: Questions for touchscreen
Posted: Wed Sep 27, 2017 6:29 am
by rpdom
OutoftheBOTS wrote: ↑Tue Sep 26, 2017 9:43 pm
As you go larger screens you usually want to have a higher res so that the pixels don't become large. As you have a higher res then the RPi needs to sedn more data so the method that you use for the RPi to talk to the screen needs to fast. The DSI ribbon is fairly fast but the HDMI is the fastest of all and HDMI screens r very common.
DSI is probably as fast as HDMI, maybe faster, but there is only one screen that is supported by DSI on the Raspberry Pi (at time of posting), and that is the official 7" one (which uses i2c on the DSI connector for the touch sensing, iirc).