Category Archives: Linux

BeagleBone Black

Posted on by
2

For my recent electronics projects I wanted something more powerful than the usual Atmel megaAVR or AVR XMEGA microcontrollers I used in the past. The obvious step upwards in performance is some embedded system running Linux. A few years ago I played a little bit with an ALIX.3D3 embedded board, but nowadays most people would start with a Raspberry Pi and I also used to have an early model of those as well. Even though the Raspberry Pi seems to be everywhere there is a better alternative in my view: The BeagleBone Black. The most obvious advantage of the the Raspberry Pi (even compared to the Model B) is the much high flexibility concerning I/O. Most important it provides with its general-purpose memory controller (GPMC) a high-bandwidth parallel memory interface which is ideal for a fast interconnection e.g. with FPGAs.
Continue reading →

CHOST: i586 vs. i486 on AMD Geode LX

Posted on by
9

On my blog post about Installing Gentoo on ALIX.3D3 Mart Raudsepp made an interesting comment: He pointed out, that on AMD Geode CPUs it might be better to use i486 CHOST instead of my used i586, because the CPU is more like a i486 as far as instruction scheduling and times go.

This sounded interesting, so I googled for some benchmark test to measure differences. I found nbench, which measures performance by executing some typical algorithms and compares them to a Pentium 90 based system. So I installed it and run on the i586 CHOST system, then rebuild it completely to i486 CHOST and run it again. Continue reading →

GPIO on ALIX.3D3

Posted on by
18

The AMD CS5536 Geode companion on the ALIX.3D3 board has several general purpose input/output pins. Most of them have different functions as well, and there are some registers to set if they should be used as special function GPIO pins. The ALIX.3D3 uses 4 GPIO pins for 3 LEDs and 1 mode switch. Accessing the leds is very easy using the leds-alix2 driver, but they can be addressed as GPIO as well. There is already a driver for the GPIO pins in the kernel named cs5535_gpio.c, but it uses a non standard interface to communicate with kernel. So, I wrote a new kernel driver using the GPIO interface. Continue reading →

Updating BIOS on ALIX.3D3 within Linux

Posted on by
8

Usually BIOS updating means booting DOS and running a proprietary tool from the board vendor. A few days ago, coreboot's flashrom 0.9 has realeased. It's an open-source tool which supports program almost all flash chips used on x86 mainboards. Its compatibility list includes Geode™ CS5530/A, which can be found on the ALIX.3D3 board. So why not using flashrom to update ALIX.3D3 BIOS.

Continue reading →