0

Grand Central and 320x480 Touchscreen Breakout
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Grand Central and 320x480 Touchscreen Breakout

by winyguy on Sun Sep 01, 2019 12:07 am

Hello.
I've connected the Adafruit - 3.5" TFT 320x480 + Touchscreen Breakout Board w/MicroSD Socket - HXD8357D to a Grand Central in serial mode and the graphics work great but the touchscreen is very sensitive and is only active for rectangular region in the center of the screen. I assume it has to do with the analog inputs but not sure. Can you tell me what needs to be updated for this display/touchscreen to work with the Grand Central?

Thanks in advance for your help.

winyguy
 
Posts: 2
Joined: Tue Aug 20, 2019 8:19 pm

Re: Grand Central and 320x480 Touchscreen Breakout

by dastels on Wed Sep 04, 2019 11:01 am

Hi there.

Have you looked at https://learn.adafruit.com/adafruit-3-5-color-320x480-tft-touchscreen-breakout/touchscreen to confirm your wiring? It's worth double checking, but since you are getting touchscreen data, I assume you are.

It would be useful to know what language and libraries you are using (C++? CircuitPython?), as well as your code that's reading the touchscreen. My thought is that you are correct and the code was written for the 10-bit ATMega analog inputs and will need tweaking for the 12-bit SAMD51 inputs.

dastels
 
Posts: 230
Joined: Tue Oct 20, 2015 3:22 pm

Re: Grand Central and 320x480 Touchscreen Breakout

by winyguy on Wed Sep 04, 2019 7:18 pm

I don't think the wiring is the issue. It does work when I connect it to other/older boards. It also works when connected to the Grand Central it's just that the touchscreen is limited to a smaller rectangular section in the center of the screen, I suspect 80x120 probably because of the increased A/D resolution. The touch is also very sensitive, triggering even when it is not touched, i.e. counts of 1-5.

I am using the Adafruit_HX8357 and TouchScreen libraries.

Thanks again for your help.

winyguy
 
Posts: 2
Joined: Tue Aug 20, 2019 8:19 pm

Re: Grand Central and 320x480 Touchscreen Breakout

by dastels on Thu Sep 05, 2019 9:51 am

Looking at the Touchscreen library, I see that he code assumes a 10 bit reading.

This post might help: https://forums.adafruit.com/viewtopic.php?f=47&t=109704

Dave

dastels
 
Posts: 230
Joined: Tue Oct 20, 2015 3:22 pm

Please be positive and constructive with your questions and comments.