Not enough GPIO pins with LCD screen attached........

azamoth

So ive got my pi up and running on a 3.5 LCD, and Ive prototyped my own gamepad PCB. Its has 10 buttons, but with the LCD attached to my pi, there are only 9 available pins.....

In the retrogame script from adafruit for the Pigrrrl (which I know is needed to run retropie with GPIO controll input) it seems the key map totaly disregards the fact that most pins are occupied by the lcd screen........Theres something here im not understanding......

could someone help clarify what I have to to do to use pins that are occupied by the LCD, or perhaps change the pin inputs from ground to input??

THANKS!!!

caver01

@azamoth I am not directly familiar with the build details (I do know about Pigrrrl), but there are a few things worth mentioning. First, Retrogame is not the only way to map buttons to keyboard inputs via GPIO pins. There are other software solutions out there. I just wanted you to be aware of that even if it doesn't directly solve your issue.

Second, the RetroGame script (and other solutions) are used by a lot of folks for projects besides just Pigrrrl. The script descriptions you are reading may apply generically, including people who are not using an LCD like you are. Still, not helping--I know.

According to this page, these are the GPIO pins mapped to their own gamepad PCB. Are you using the same?

These pins don't interfere with their display according to this statement about the screen they are using:
"The display and touchscreen uses the hardware SPI pins (SCK, MOSI, MISO, CE0, CE1) as well as GPIO #25 and #24. All other GPIO are unused. "

cyperghost

@azamoth
As @caver01 told you there are several ways... and your display just needs a few Pins as told....

If nothing else helps use MCP23008 or MCP23017 gpio expanders and connect to I2C-bus. But please don't ask me how to do this. Never used that :)