Driving a Large E-Paper Display with a Compact Xiao RP2040
How to drive a large e-paper display?
E-paper displays require an external frame-buffer, hence the need for a large SRAM.
For example, the 960x672 9,7" black-white-red e-paper panel requires 161280 bytes and the 960x768 12.2" black-white-red e-paper panel 184320 bytes to store the image to be displayed.
The projet includes the Seeed Xiao RP2040 board, the Pervasive Displays EXT3 extension kit, the EXT3-Giant expansion board, and the 9.7" black-white-red e-paper display.
The hardware was sampled by Seeed Studio and Pervasive Displays.
The large e-paper panels are driven by two controllers, hence the need for the EXT3-Giant expansion board and two chip select signals.
Connections between the Xiao RP2040 and the EXT3 extension board include:
The PDLS_EXT3_Basic library provides all the tools to drive the e-paper panel.
It relies on the Arduino SDK. Installation goes through the standard procedure.
However, the library doesn't include the Xiao RP2040 board by default.
Defining it is easy: just create a pins_t structure and mention the GPIOs for the signals needed.
NOT_CONNECTED mentions the signal is not implemented.
Using the GPIO numbers instead of the pins names proved to be easier.
The example used for the project is Common_Colours.
Open the Common_Colours.ino file, add the boardXiaoRP2040 board definition and edit the Screen_EPD_EXT3 constructor accordingly.
Posted: 22 Apr 2022