pangren
Posts: 42
Joined: Thu Dec 19, 2013 2:52 pm

Connecting TFT LCD and buttons, but not enough GPIO

Tue Jan 24, 2017 2:30 pm

Hi I , like many others , are trying to make a handheld retrogaming machine. I've just managed to wire up a Waveshare 3.2" TFT LCD to the Raspberry pi 3 and get it to work.
http://www.waveshare.com/3.2inch-rpi-lcd-b.htm

But however It took up quite a bit of my GPIO Pins and I also want to connect a PIGRRL PCB
https://www.adafruit.com/products/3015 to it.

I realize that, unlike the Adafruit TFT screens, the waveshare screens don't have additional breakouts after it is connected to the Pi. Is there anyway I can overcome this?

ahmedawad
Posts: 42
Joined: Mon Apr 18, 2016 11:44 am
Location: Bremen, DE

Re: Connecting TFT LCD and buttons, but not enough GPIO

Tue Jan 24, 2017 3:35 pm

you will need a port expander. Attach some thing like this using the I2C and you communicate with your ada fruit board and let the waveshare LCD run on the SPI
http://www.mouser.com/ds/2/100/CY8C95x0 ... -35848.pdf

regards

wyliecoyoteuk
Posts: 4
Joined: Tue Jan 24, 2017 8:45 am

Re: Connecting TFT LCD and buttons, but not enough GPIO

Wed Jan 25, 2017 8:11 am

The display actually only uses about half the pins.
3, 5, 7, 8, 10, 12, 13, 15, 16 are not connected, so something like this might help:
https://www.piborg.org/triborg

pangren
Posts: 42
Joined: Thu Dec 19, 2013 2:52 pm

Re: Connecting TFT LCD and buttons, but not enough GPIO

Wed Jan 25, 2017 2:44 pm

Hmm... in that case, i'm not going to be able to connect all the buttons i need. If the TFT has some function that I don't use eg. touchinput pin19, And i use the triborg and connect a button to pin 19, will the button work? or will i have to somehow disable pin 19 for the TFT screen?

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