User:Istitov/Adafruit PiTFT

Adafruit Industries produces whole series of resistive and capacitance touchscreens displays suited for all generations of Raspberry Pis computers. Original PiTFT 2.8" and PiTFT 3.5" screens fit on Raspberry Pi's A and B and overhang slightly over the USB-ports on more modern versions. 2x20 GPIO pins adapted PiTFT Plus 2.8" and 3.5" do not have this problem, however, they cannot be used with classical A and B models with 2x13 GPIO pins. 2.8" and 3.5" versions have 320x240 and 480x320 screen resolution, respectively; 2.8" model features additional GPIO-connected ports, which could be fit e.g. with hardware buttons. The screen resolutions available may be not enough for modern DE, however, the touchscreen can be used for some simple mini monitor with framebuffer console or even X11 output (e.g. conky).

Adafruit provides extensive installation instructions via the python script, however, the script adapted for Raspbian/Raspberry Pi OS does not work well under Gentoo. Following instructions are written based on the above mentioned script and this slightly outdated text. .

Prerequisites
The display and touchscreen uses the hardware I2C Pins (SDA & SCL), SPI pins (SCK, MOSI, MISO, CE0) as well as GPIO #25 and #24. Additionally 2.8" version uses GPIO and 2.8" Plus version 17, 22, 23, 27 All other GPIO are unused and you can still share the I2C pins with sensors, LED drivers, etc. Since we had a tiny bit of space, there's 4 slim tactile switches wired to four GPIOs, that you can use if you want to make a basic user interface. For example, you can use one as a power on/off button.