Pervasive Displays e-Paper Screen with Fast Update

One of the major complain about e-paper screen is the slow update. Here is an interesting solution.

Pervasive Displays has launched a new version of the 2.71" e-paper screen with embedded fast update.

The page for the 2.71" screens now contains two references:

E2271CS091 for the standard screen; and
E2271PS091 with the embedded fast update.

How does fast update compare with global update?

The screens were sampled by Pervasive Displays.

Test

Let's first see the video of the test before exploring the hardware and software used.

Hardware

The board is a Raspberry Pi Pico with the arduino-pico boards package from Earle F. Philhower. The details of the connection to the EXT3 extension board are available here.

The corresponding parameter passed onto the object contructor is boardRaspberryPiRP2040Pico.

Software

The code is identical, except the library.

epaper_ext3_basic_fast.ino
File Size:	3 kb
File Type:	ino

Download File

For global update, the library is PDLS_EXT3_Basic, available at this GitHub repository.

The class is Screen_EPD_EXT3 with the screen eScreen_EPD_EXT3_271.

The text to be displayed is GLOBAL UPDATE.

For global update, the library is PDLS_EXT3_Basic_Fast, available at this GitHub repository.

The class is with the screen eScreen_EPD_EXT3_271_Fast.

The text to be displayed is FAST UPDATE.

This is the main function displayMode().

The initialisation sets the orientation of the screen and selects the font.

The text is sent to the frame-buffer and then the screen is refreshed. The chrono variable records millis() before and after, and calculates the difference.

The time spent in ms is then displayed on the screen.

The main setup() function initiliases the serial UART and the screen, then launches the main function displayMode().

After 8 s, the screen goes through a unknown-black-white cycle to clean possible ghosting.

The main loop() function does nothing.

Conclusion

The global update takes 3545 ms, while the fast update 977 ms only, or 3.6 times faster. Quality is excellent with no traceable ghosting.

The Pervasive Displays 2.71" e-paper screen with embedded fast update provides an interesting option for a faster e-paper screen.