I use a TS-7260 and thought I was having the same problem. I was
using a series of optomos switches off the DIO to do polarity reversal
on a solenoid. If the all DIO came up "high" then the 5V line would
be shorted directly to ground...yet that never happened.
My software engineer initially told me that we could set them default
low at startup, then later retracted after our unit was built and
powered up for the first time.
I was then told, the outputs are high until about 11 seconds into the
boot when his script changes them to low.
I couldn't get past the fact that my 5V line was never shorting
out...until I replaces the optomos' with LEDs. On powerup, the LEDs
would glow very very faintly, 11 seconds in, they would go out, then
as I activate the polarity reversal commands, two LEDs at a time would
come on very bright.
My conclusion was that the outputs are high, but unable to source any
real current...at least not enough to turn on my relays.
Is it possible that they are coming up as inputs, and that the voltage
we are seeing is really just from the internal pull-up resistors on
the DIO? This would explain why you read ~3.3V on those pins at
startup. Dangerous indeed if they attempt to source current,
especially in my case.
I have since changed my design, so I can't be caught off-guard with
these kinds of situations, but thought you guys might benefit from my
anecdotal observations.
-Terrance
> -- In "minulescu" <minulescu@> wrote:
> >
> > >
> > > It seems that the DIO pins are set on 3.3V at boot time, after all.
> > > Has someone find a way to eliminate this?
> > >
> > > Thanx,
> > > Razvan
> > >
> >
> > Yah, I'm going to change what I said once again. The DIO pins are set
> > at 3.3V on startup indeed. When I rechecked the outputs and came up
> > with 0V, I forgot the fact that I was turning them off initially
> > in /etc/rc.c/rcS.sysinit.
> >
> > But like I already said in the initial post, this takes 3-4 seconds
> > to deactivate them, so I don't know if that's good enough for you
> > Razvan.. probably not.
> >
> > Thus, I too, am still looking for a solution to this.
> > Sorry for all the confusion.
> >
> > -Minulescu
> >
>
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