st7735: Add dump with unknown command

[sigrok-dumps.git] / display / st7735 / README

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ST7735 TFT display controller, 4-wire SPI
-------------------------------------------------------------------------------

This capture contains ST7735 TFT display controller communication which is
popular for small (1.44", 1.8") 16-bit color display modules. The protocol
of these modules is based on SPI, but unlike typical SPI has no MISO and uses
two additional pins called RES (reset) and DC (data / command).

Details:
https://cdn-shop.adafruit.com/datasheets/ST7735.pdf
https://github.com/adafruit/Adafruit-ST7735-Library


Logic analyzer setup
--------------------

The 1.44" 128x128 px module was driven by Arduino Uno and Adafruit ST7735
library. The capture was taken with 8 channel noname Saleae logic analyzer
clone, sampling 5 logic channels at a rate of 24MHz:

  Probe       ST7735
  ------------------
  0           CS   (chip select)
  1           RES  (reset)
  2           DC   (data / command)
  3           MOSI (master out, slave in)
  4           SCLK (clock)


Data
----

This is a minimal capture despite the fact that it might look otherwise. It
contains an initialization of a display and filling it with one complete frame.
Long pauses are caused be sleeps for a few hundreds of milliseconds, which are
required by the spec. Other oddities like frequent changes of CS are caused by
specific library implementation.


Dump with unknown command
-------------------------

Taken with the same setup as above on a 128x160 display with Arduino TFT library
and the following code:

  #include <TFT.h>
  #include <SPI.h>

  #define cs   10
  #define dc   9   // A0
  #define rst  8

  TFT TFTscreen = TFT(cs, dc, rst);

  void setup()
  {
    TFTscreen.begin();
    TFTscreen.background(0, 255, 0);
  }

  void loop()
  {
  }