the other way to use the DIO pins to control an LED is to use the DIO lines to
"Sink" the current.
see figure 4 in this document:
http://www.siriusmicro.com/projects/b2.pdf
-Curtis.
On January 4, 2006 07:13 pm, Matthieu Crapet wrote:
> Greetings,
>
> Your TS-7xxx board has got two leds (green and red), for startup, you
> could patch the kernel
> for you need.
> A script in init.d could inform you that the "software" is ready.
>
> You can't directly connect a led you the DIO because, DIOs can be source
> 4 (or
> 8) mA and your led need at least 10mA ; you will need a transistor (I
> spammed
> the list with that ;))
>
> The topic has been discussed numerous times, "DIO" is a good keyword to
> search.
>
> These specific threads could be interesting for you:
> - "[electronic] 7-segment LED" (10.30.2005)
> - "DIO code" (07.11.2005)
> - "DIO example code..." (11.30.2004) <= fits your question
>
> I attach you a geda schematic for your need (using NPN, 2N2222), hope it
> helps (this is tested!).
>
> Matthieu
>
>
> Yan Seiner wrote:
>
> >I've got a couple of questions on LEDs....
> >
> >Anyone know of a way to turn on an LED as soon as the power is applied
> >and then turn it off under software control? I am trying to get an
> >indicator that the power is applied and the system is booting....
> >
> >Also, anyone know of a packaged LED that can be driven directly off of
> >one of the DIO pins? I am thinking of a light assembly that takes TTL
> >levels as input, and has a separate 5V power, and turns on and off
> >with TTL control? (Am I making any sense at all? I just came back
> >from Japan and I'm still jet-lagged quite a bit....)
> >
> >--Yan
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
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