PiGFX is a bare metal kernel for the Raspberry Pi that implements a basic ANSI terminal emulator with the additional support of some primitive graphics functions. It can be driven by pushing characters to the raspi UART. Additional functions like changing text color, moving the cursor or clear the screen can be invoked via ANSI escape codes. The result is that you can easily add an HDMI display output to your embedded project without the hassle of directly generate the video signal.
This work is inspired by Spencer’s project that aims to create a cheap graphics card and keyboard interface to its homebrew Z80 computer. PiGFX has the advantage of removing the fuss of having a full-featured Linux system running on your raspi. This dramatically decreases the boot time, lets the system be more customizable and, of course, adds a lot of fun.