ST7735 TFT-Library for PIC-Microcontrollers

Status

The code compiles and runs. Tested with a PIC12F1840/PIC16F1829 and xc8. Note that with the defaults from demo/Makefile, the code just fits into the PIC12F1840 (uses 4072 of 4096 words, free version of xc8). The library code itself is much smaller (about 2K), the rest is test-code.

Using glyph-fonts needs a lot of memory, here you need larger PICs (e.g. the PIC16F1829 with 8K of flash).

Overview

This is a port of the Adafruit ST7735-library for PIC microcontrollers. The code is a copy of https://github.com/gavinlyonsrepo/pic_16F18346_projects with some added features (TFT_ENABLE_*-defines, rotation) and some modifications to make the code compatible with my pic-toolchain.

To use the code directly, you have to install the makefile-rules and header files of the toolchain. Otherwise, copy the lib and include directories and use the code and makefile within demo as a starting point. You will have to edit include/hw.h. If you don't want to use my pic-toolchain (or if you port the code to a different platform), you must also supply your own version of include/spi.h.

Library-configuration

The library has many functions and to keep the footprint small, you must selectively include only the features you need. Currently, the library supports the following #defines, which you should set in the makefile:

• TFT_ENABLE_ALL: enable all features
• TFT_ENABLE_BLACK: "black"-type TFT
• TFT_ENABLE_GREEN: "green"-type TFT
• TFT_ENABLE_RED: "red"-type TFT
• TFT_ENABLE_GENERIC: "generic"-type TFT
• TFT_ENABLE_RESET: use reset-pin during initialization
• TFT_ENABLE_TEXT: enable text-functions
• TFT_ENABLE_SHAPES: enable shape-functions
• TFT_ENABLE_SCROLL: enable scroll-functions
• TFT_ENABLE_ROTATE: enable rotation
• TFT_ENABLE_FONTS: enable glyph-fonts (see below)
• TFT_ENABLE_BMP: enable bitmap-functions (not usable yet)

Fonts

The ST7735-library uses a small standard-font, which is impossible to read unless you are really near the screen. You can scale the font, but the result is ugly.

The solution to the problem are glyph-fonts. They take up a lot of space (2.5K-4K and more), so this might not fit into the available flash.

This repository only distributes a single glyph-font lib-st7735/include/FreeMonoOblique12pt7b.h, others are available from the original Adafruit project https://github.com/adafruit/Adafruit-GFX-Library/.

To use these fonts, you need to #define TFT_ENABLE_FONTS and set the font before drawing text. See Test9() in the demo-program for an example.

Font-Subsets

Very often, a complete font is not necessary. This project provides a utility to create a subset of the font only with the necessary characters in the subdirectory fc_subset. You should read complete instructions in the above mentioned Adafruit-repo.

Handling of subsets needs some care, see Test9A() for an example.