[sdiy] Raspberry Pi

[BARRY KLEIN]

Hi Eric,
We are starting to get into a lot of embedded Linux products at work - NAS boxes, TV media gadgets, etc.
The book you refer to seems to be a good one.  Checking at the publisher site there is a new 2nd edition.  Do you have this?  I am curious if there is new material worth spending for.

Barry

On Nov 20, 2011, at 9:33 AM, Eric Brombaugh wrote:

> Paul,
> 
> In general there are fairly high-level APIs for accessing the I2C, SPI and GPIO pins from within userspace applications under Linux. The main difficulty is in setting up the hardware and Linux kernel data structures to enable them. I've done a lot of work over the last few years in this area using the Beagleboard and while at the high level it looks pretty easy, there are a lot of details involved. If the folks who are packaging the Linux OS for Raspberry Pi manage to get these details done for you then it should be simple. If you have to do it yourself (eg, they didn't enable out-of-the-box a hardware interface you need) then be prepared for a few months of drinking from a firehose to get it working yourself. This is the scenario in which easy access to the hardware documentation becomes essential, and if it's not available can be a show-stopper.
> 
> It's true that writing application code intended to run under Linux is a vastly different exercise than coding for bare-metal on a low-end MCU. On the one hand you can't just go out and poke at a hardware register because the OS won't let you do that and you need to keep in mind that your code isn't the only thing running on the machine. On the other hand, many of the difficult things a bare-metal program needs to do are handled for you by the OS, and generally development/debug is much easier.
> 
> As far as resources go, you might consider something like this
> 
> http://www.amazon.com/Embedded-Linux-Primer-Practical-Real-World/dp/0131679848
> 
> Bearing in mind that embedded linux development is a very rapidly growing topic and printed matter goes stale pretty quickly. The best way to do it is find an active online community focused on your hardware platform of choice and follow along.
> 
> Eric