Re: What is the Purpose of GPIO Controller.

Re: What is the Purpose of GPIO Controller.

[krishna]

Hi Ian,

    Thank you very much.
    My doubt is,
    I have a board here where all lines to the peripherals are highly 
multiplexed and
    I had to configure these lines. Now my Wireless Ethernet Driver has 
a conflict with
    the audiocodec driver. What I mean is, if I load the WLAN driver and 
try to load the
    audiocodec driver next, the audiocodec driver is not responding.

    I traced the bug to be sharing of GPIO Lines.

    Form your mail I understand GPIO controller serves some Hardware 
designers purpose.
    But what _purpose_ is it serving a _programmer_.

Regards,
Krishna Chaitanya

Re: What is the Purpose of GPIO Controller.

[Ian Campbell]

On Tue, 2005-02-15 at 19:57 +0530, krishna wrote:
> Form your mail I understand GPIO controller serves some Hardware 
> designers purpose.
> But what _purpose_ is it serving a _programmer_.

All a gpio controller does is allows the programmer to configure a line
as an input or an output, and then either read it or make it high or
low.

This allows the programmer to control the hardware. Exactly how and what
you control it is 100% a function of what the hardware designer has
done.

Unless you have access to documentation or the hardware engineers brain
you'll just have to work out what each line does by trial and error.

Ian.



-- 
Ian Campbell
Current Noise: Opeth - To Rid the Disease

Variables don't; constants aren't.

Re: What is the purpose of GPIO Controller.

[krishna]

Thank you very much.