[Soekris] LED controller

[Pete Kay]

Hi

Thank you for your suggestion.  I have got a few 74HC595 ICs and I
would like to try to use GPIO to drive this IC which will then in
light up the LED.

Does anyone know how to use GPIO to generate the CLK signal?  I know
74HC595 needs CLK, Latch, and Data-in.   Where can I find any tutorial
on how to use 3 GPIO pins to drive this IC?   How do I synchronize
these three signals?   Please forgive my newbie questions as I am just
beginning to learn about gpio.

Any help or hint or pointer will be greatly appreciated.

Thanks,
P

On Sat, Aug 7, 2010 at 3:27 PM, Alvar Kusma <alvar at raamat.polva.ee> wrote:
> Pete Kay kirjutas:
>
>> I am trying to have my Soekris board to somehow control a set of 16
>> LEDs,
>> What are the components that I can purchase
>> off-the-shelf for this kind of thing?
>
> Net5501 has 12 general purpose IO pins on JP5, which are accessible from
> userspace. But if you need more than that, then use PIPO register like two
> 74573-s latches, connected to GPIO pins (if i remember correctly, then
> PC87366 is 5V tolerant). Software then is a bit more complicated, but not
> much.
>
> Another way is to use SIPO registers. For realization example see
>
> http://www.arduino.cc/en/Tutorial/ShiftOut
>
> Simplest way of course is to try directly with existing GPIO-s, but this
> limits LED count to 12.
>
> --
> =<Alvar>=
>