Tiny Terminal 2

This article describes a text display based on a 256x64 OLED display that provides 8 lines of 42 characters per line. Its width makes it ideal for displaying text or program listings, unlike the more common 128x64 displays.

The display is driven by a standard 9600 baud serial interface, making it ideal for debugging serial devices, or as a self-contained character display for a project. Both the display and serial input are handled by an 8-pin ATtiny85, and it’s based on my earlier project Tiny Terminal.

Design
I’m always on the lookout for interesting displays, as the basis for new projects, and I found this 256x64 greyscale OLED display offered by a supplier on Aliexpress [1]. It allows you to have a text display of eight lines with 42 characters per line, which is just about large enough for reading text, and is ideal for program listings. It’s based on an SH1122 driver chip.

Note that unlike most other OLED displays this display is 3.3V, so you should take care not to drive it directly from 5V. The circuit below includes a 3.3V regulator, and a level shifter for the serial input.

The Tiny Terminal 2 circuit uses an ATtiny85, and it takes advantage of the fact that the display stores the data written to the display in its own internal memory, so there’s no need for a separate memory buffer. It uses the display’s built-in hardware scrolling to scroll the display up when the text reaches the end of the last line.”

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