====== Medium Graphic LCDs and classic Arduinos ======

===== Summary evaluation =====
  * 128x64 LCD display with ST7920 controller.
  * 2.9" --- offers moderate DPI.
  * Since they are monochrome devices, the expected data load they present to the microcontroller is, unlike TFT displays, relatively low.

In the tests that follow, I am striving to answer first whether the rendering updates will be fast enough for reasonable use and second whether there will be any memory left to do anything interesting.

They are certainly fast enough, but the required program storage and dynamic memory isn't trivial.

===== Tests =====

Tests belows were done with a 16 MHz 5V Nano using an STN module from an Asian source. I only tested the hardware SPI interface.

==== U8g2 ====


Oli Kraus' [[https://github.com/olikraus/u8g2/wiki | U8g2]] is intended to be a common platform for interfacing to a whole bunch of different monochrome displays. It supports the ST7920 controller chip out of the box.

The frame update time of 106 ms with a 16 MHz processor (the inverse of the fps noted in the [[ display_st7920_126x64_u8g2.ino | source code]]) is respectable, and character change artifacts are not objectionable. Memory use is on the order of 46% of program storage space and 27% of dynamic memory on a Nano.

A video of this setup isn't available. Sorry. :-/

[[ display_st7920_126x64_u8g2.ino | source code]]