Asyncronous 1-wire interface?
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From: rickman on 19 May 2010 18:30 On May 19, 5:36 pm, Ulf Samuelsson <u...(a)a-t-m-e-l.com> wrote: > Leo Havmøller skrev: > > > Hi, > > > Im looking for a short-range (20 cm) 1-wire I/O interface that is fully > > asyncronous. > > Does such a thing exist? > > > Leo Havmøller. > > I know of a single wire interface, which is bidirectional > and multiplexes data with VCC and GND on a single wire. > > Two units, one have a battery and the other one does not > have any power source, but is powered, when in contact with the > first unit through the single wire. > > Cant reveal any details, but it is a known fact > that it is easier to solve a problem, once one knows > it is solvable ;-) I would like to see that interface. I guess it is capacitively coupled and uses a charge pump to maintain power level? Or maybe you aren't describing it correctly when you say Vcc and GND are muxed on the same wire??? The 1-wire protocol I am familiar with uses a wire for everything else and a second wire for ground. Rick
From: rickman on 19 May 2010 18:32
On May 19, 5:42 pm, larwe <zwsdot...(a)gmail.com> wrote: > On May 19, 5:36 pm, Ulf Samuelsson <u...(a)a-t-m-e-l.com> wrote: > > > Two units, one have a battery and the other one does not > > have any power source, but is powered, when in contact with the > > first unit through the single wire. > > Sounds like a novel application of an RFID chip. Sounds to me like a device that is overspecified and could use a 1- wire interface... "1-wire" as in the Dallas interface. Bloody hell, if the clock is turned off, how does the chip run??? When a transition is detected, start the clock and read the message! Rick |