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LCD Display + Pushbuttons = GPIO conficts?

Posted: Fri Jun 03, 2016 11:16 pm
by Jakobud
I'm new to RPi projects. I'm wanting to make a small arcade cabinet using an small LCD display as well as hooking up pushbutton microswitches and a joystick to the GPIO pins. I am using a RPi 2 Model B V1.1.

Both of these things are independantly possible. But it seems like if I try to do both at the same time, there aren't enough GPIO pins to accomplish both.

So this is what i'm looking at:

Waveshare 4inch LCD:

Here is the board for it: Image ... -a-2_1.jpg

Image ... CD-A-4.jpg

Looking at the connector, it takes up a LOT of the GPIO pins. It appears to use pins 1-26

Now regarding pushbuttons and joysticks, I haven't yet looked in detail as to which GPIO pins they would connect to. It looks like, the available pins left over would be 27-40, which leaves I think 9 GPIO pins and the rest are GND? So does that mean I can use a maximum of 9 pushbuttons when I'm using the LCD?

Are there any alternatives to hooking up or using this LCD screen that would open up some more GPIO pins for me to use? Or is the LCD using actually ALL of the pins with that connector? I can't really tell.

Sorry if these are total noob questions. I'm just trying to figure out my options before diving into this.

Re: LCD Display + Pushbuttons = GPIO conficts?

Posted: Sat Jun 04, 2016 12:27 am
by DirkS
The waveshare page you link to shows which (physical) pins are used / free (NC is not connected).

Code: Select all

3, 5, 7, 8, 10, 12, 13, 15, 16	NC	
Looking at and leaving out the I2X and UART pins there are 5 general purpose pins available
Then there are another 9 at the 'high' pins.

Re: LCD Display + Pushbuttons = GPIO conficts?

Posted: Sat Jun 04, 2016 5:20 am
by tinylcd

below is a one more display option which has a 40 pin header instead of 26 pin header so more gpio are easily accessible ... 7&cPath=20