cynceyd / it8951

Driver for the IT8951 e-paper controller on Raspberry Pi

IT8951

This Python 3 module implements a driver for the IT8951 e-paper controller, via SPI. The driver was developed using the 6-inch e-Paper HAT from Waveshare. It hopefully will work for other (related) hardware too.

To install, clone the repository, enter the directory and run

pip install -r requirements.txt
pip install ./

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For some examples of usage, take a look at the integration tests.

Notes on performance

VCOM value

You should try setting different VCOM values and seeing how that affects the performance of your display. Every one is different. There might be a suggested VCOM value marked on the cable of your display.

Data transfer

You might be able to squeeze some extra performance out of the data transfer by increasing the SPI clock frequency. The SPI frequency for transferring pixel data is by default set at 24 MHz, which is the maximum stated in the IT8951 chip spec here (page 41). But, you could try setting higher and seeing if it works anyway. It is set by passing the spi_hz argument to the Display or EPD classes (see example in tests/integration/tests.py).

Updates for version 0.1.0

For this version the backend was rewritten, so that the SPI communication happens directly by communicating with the Linux kernel through /dev/spidev*. This means:

• sudo no longer required
• requires neither the bcm2835 C library nor the spidev Python module
• data transfer is way faster than before!

Hacking

If you modify spi.pyx, make sure to set the USE_CYTHON environment variable before building---otherwise your changes will not be compiled into spi.c.