Author Archives: Jason J

Raspberry Pi SPI Speed and LPD8806 RGB Strips using Python

So we recently decided to move this project to the Raspberry Pi board away from Arduino. The capabilities and processing power of the Pi are much greater than Arduino. The Raspberry Pi community is growing extremely fast and amazing projects are happening everywhere.

We have successfully loaded images into the SGEB, but the refresh rate is too slow, much slower then the Arduino was. We need some help figuring out how to turn up the SPI speed with our current software arrangement.

I used  Brian Hensley’s method for loading the SPI drivers on to Wheezy http://www.brianhensley.net/2012/07/getting-spi-working-on-raspberry-pi.html

Then used Phillip Burgess’ at Adafruit ‘Light Painting’ Python script to process images and output to the LPD8806 http://learn.adafruit.com/light-painting-with-raspberry-pi/software

The image processing script is amazing and solves tons of problems we had with the Arduino.

But I can’t figure out how to set the SPI speed through the Python scripts. 

I had attempted to use the Occidentalis OS as Adafruit suggested but the SPI Max Speed is set to 500 Khz in arch/arm/machbc2708/bcm2708.c   Compiling a Kernel proved to difficult for me to manage.

Am I mistaken that the SPI drivers are different between the 2 methods?