segunda-feira, 30 de abril de 2012

uClinux - Hello world!


Hello World!

Usually this represents the very basic program someone can compile. In this case it's a true salutation to the whole world - The Internet.

With the FPGA around, connecting a simple ethernet controller from Microchip (the enc28j60) was a piece of cake. The chip interface is a simple SPI slave port that even provides 5V tolerant IO's.

An experimental linux driver for kernel 2.4 is easily found here: http://elinux.org/Enc28j60 (linux kernel 3.x tree already has support fot this chip). So, all I had to do was to rewrite the SPI function calls, and that was it...

My kernel image size has grown significantly with the addition of network support, so memory limitation is (again!) my greatest pain.

Here is a small video showing the system running the 'boa' web server (it show nice comments during playback):







Having reached this far, and starting to struggle with low memory issues, I've lost my mind and decided to put all this stuff on a PCB!

On the next post I'll show the specifications, peripherals and the PCB itself.

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