[chbot] Low level documentation for Raspberry Pi GPIO and so on.

[hamster]

Hi Mark, 

Apparently a large portion of the BCM2835 ARM SOC peripherals are
documented in free-as-in-beer documentation. See
http://www.element14.com/community/docs/DOC-43016/l/broadcom-datasheet-for-bcm2835-soc-used-in-raspberry-pi
for a 200+ pages including the the GPIO, SPI, UARTS and so on.

This will be a surprise for some who believed that Broadcom wouldn't
provide enough documentation to make the Raspberry Pi usable. 

At NZ$55 maybe it will oust Arduino and become the de facto robotics
controller... (although 5V 700mA is quite a lot of juice).

Mike