Rockbox mail archive
Subject: Re: AW: AW: AW: AW: AW: Still Problems with AJB Remote
From: Ronald Teune (rtwolf_at_gmx.net)
On Wed, 14 Jul 2004 22:17:54 +0200, Matthias Klumpp
> Hi Ronald,
> # What if we used standard 1N4148 diodes?
> # The voltage drop on the Schottky diode is 0.6 Volts.
> # If the uC out port is at 0 V, the AJB remote line will be pulled
> # down to 0.6 V;
> Isn't it less voltage drop in case of a Schottky ?
> As I understood Jörg, he wants the Schottky because of a lower voltage
> than 0.6V when the uC port is 0V.
I meant to say I was doing in-brain circuit simulation with standard
1N4148, but perhaps wasn't very clear :-)
> # when the uC Out port is at 5 V, the AJB remote is at ~5 V due to
> # the pullup.
> That's still making me ?????????, because I still have that 5V level on
> JB side.
> What if I make a resistor voltage devider, that makes the pull-up pull to
> 3.3V, like this:
> | |12k
> | |
> | |
> +-+ |
> | |22k |
> | | |
> +-+ |
> | |
> --- |
> Schottky |
> uC Out port--------|<|---------+-- AJB remote
> # (it's easy to make mistakes though, with this kinda stuff,
> # especially since it's holiday - so correct me if i'm wrong)
> You are wrong - still NO holidays in Germany ;-)))
> Even so it's already a little bit late here and forthermore after a hard
> days work....
> maybe therefore ?
Hehe... again I probably was unclear... I meant that _I_ had holiday, so
_I_ could be wrong :-)
That voltage divider thingy is probably cool too.
Maybe the best and fastest way to correctly simulate is just take 5V, a
multimeter, a diode and two resistors :-)
> # Perhaps PSPICE has some problems with grounding and stuff; how
> # exactly did you connect a ground to this schematic?
> Well the schematic is only "the upper half" of the circuit.
> I've taken a pulse generator symbol to get a 20ms/5V rectangle signal as
> uC out.
> On the AJB remote side I have a 1M resistor to ground (simulating a high
> impedance input).
hmm... sounds right... well, whatever :-P
I would like to build a remote too, I think it'll be quite useful. And the
one Steve Russel describes seems dirt cheap, so why not... the problem
would be a decent, small enough box to put the buttons and PIC in and not
to be too big. Is your design better? ;-)
Ronald (aka zeekoe)
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