What is the purpose of GPIO pins.

What is the purpose of GPIO pins.

[krishna]

Hi all,

    Can any one tell me the purpose GPIO pin serves.
    How are GPIO pins better than dedicated pins, considering hardware 
design view and for programming view.
 
Regards,
Krishna Chaitanya

Re: What is the purpose of GPIO pins.

[linux-os]

On Tue, 15 Feb 2005, krishna wrote:

> Hi all,
>
>   Can any one tell me the purpose GPIO pin serves.
>   How are GPIO pins better than dedicated pins, considering hardware design 
> view and for programming view.
>

Do you mean General Purpose I/O bits on a chip?
             ^       ^       ^ ^
If so, it is intended to live in the lower 16 megabytes of
an ix86 machine (higher addresses are not decoded), and at one
time, went to the ISA bus, but is now usually a simple
asynchronous bus off from some bridge.

>From a hardware perspective, it's slow. From a programming
perspective, you don't care where it is.

> Regards,
> Krishna Chaitanya

Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
  Notice : All mail here is now cached for review by Dictator Bush.
                  98.36% of all statistics are fiction.

Re: What is the purpose of GPIO pins.

[krishna]

Hi,

    NO,  Sorry I wasn't clear.
    I am asking about GPIO controllers used in HandHeld Devices.
  
Regards,
Krishna Chaitanya

linux-os wrote:

> On Tue, 15 Feb 2005, krishna wrote:
>
>> Hi all,
>>
>>   Can any one tell me the purpose GPIO pin serves.
>>   How are GPIO pins better than dedicated pins, considering hardware 
>> design view and for programming view.
>>
>
> Do you mean General Purpose I/O bits on a chip?
>             ^       ^       ^ ^
> If so, it is intended to live in the lower 16 megabytes of
> an ix86 machine (higher addresses are not decoded), and at one
> time, went to the ISA bus, but is now usually a simple
> asynchronous bus off from some bridge.
>
>> From a hardware perspective, it's slow. From a programming
>
> perspective, you don't care where it is.
>
>> Regards,
>> Krishna Chaitanya
>
>
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
>  Notice : All mail here is now cached for review by Dictator Bush.
>                  98.36% of all statistics are fiction.
>
>

Re: What is the purpose of GPIO pins.

[Robert Schwebel]

On Tue, Feb 15, 2005 at 05:53:00PM +0530, krishna wrote:
>    NO,  Sorry I wasn't clear.
>    I am asking about GPIO controllers used in HandHeld Devices.

Embedded CPUs usually have general purpose I/O pins for all kind of
stuff; you can just use them as inputs (for example for reading
keyboards), outputs (e.g. setting LEDs) or use them as interrupt
sources with various properties (level, edge, ...). 

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
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