bersch / ST7735S

an OS independent library for the neat ST7735S 80x160 IPS 0.96" TFT-Display

ST7735S

a portable library for the neat ST7735S 80x160 IPS 0.96" TFT-Display

Features

• MIT License
• portable
• Implements: Pixel, fillScreen, Line, Rect, filledRect, Circle, Arc, Pie, Color, Fonts
• BDF-Font converter included (bdf2c.pl)
• super fast with buffered writes
• great improvement on low mem with HVBUFFER

Architecture

+-----+---------------+
|     |   GFX/Fonts   | gfx.c, fonts.c
+     +---------------+
|       Driver        | st7735s.c
+---------------------+
|   SPI Compat Layer  | st7735s_compat.c
+---------------------+
|        OS-API       | Arduino/STM32/...
+---------------------+

Adapt this driver to your desired Platform by editng the st7735s_compat.c file.

Buffered writes speeds up everything. Implemented are three buffer modes:

• BUFFER1 - actually no buffered writes, slow, for limited ram.
• HVBUFFER - one line buffer with WIDTH * 2 bytes size. Acts as for either row or column buffer.
• BUFFER - full frame WIDTH * HEIGHT * 2 bytes size. very fast.

The HVBUFFER is based on the fact, that due to design of the ST7735 to write a single pixel one need to write 13 bytes on the SPI bus. For two bytes that are adjacent in horizonal or vertical direction one need to write 15 bytes. HVBUFFER stores one pixel and checks if the following pixel is adjacent. Depending on the next pixel HVBUFFER acts like a row or column cache as long as following pixels are adjacent. If the next pixel is not adjacent, the cached pixels are flushed. Therefore the last action needs to be flushBuffer().

However if you use Arduino on Atmega328 compile with -DBUFFER1 to reduce memory usage. Perhaps HVBUFFER will work as well.

This library uses the Terminus Font available at http://terminus-font.sourceforge.net/

In order to use your desired BDF-fonts use the ./tools/bdf2c.pl script. The bdf2c.pl script can only handle fonts with fixed width.

The chars of a font can be limited by defining a range i.e. '0-9'.

Quick Steps

Copy st7735s_compat.h.default and st7735s_compat.cpp.arduino to your project dir and rename them to .h and .cpp. Edit those files and modify them for your needs. Link to ST7735S library. You'll need to insert also includes to your code

#include "st7735s.h"
#include "fonts.h"
#include "gfx.h"

Wiring

   MODULE                   MCU 
   ------                   ---
           \              /
    GND    |--------------| GND
           |              |
    VCC    |--------------| VCC
           |              |
    SCL    |<-------------| SCLK (SPI Clock)
           |              |
    SDA    |<-------------| MOSI SPI (Master Out / Slave In)
           |              | 
    RES    |<-------------| Reset
           |              |
    DC     |<-------------| Data/Command
           |              |
    CS     |<-------------| CS (Chip Select)
           |              |
    BLK    |<-------------| Backlight (PWM)
           |              |
           /              \

• Resources

Datasheet: (https://www.crystalfontz.com/controllers/Sitronix/ST7735S/320)