Asyncronous 1-wire interface?
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From: Leo Havmøller on 2 May 2010 01:15 > This sounds like you are creating a chip. You wrote that the clock of the > chip can change, but I'm sure that the chip has some stable internal clock > reference, or at least within the chip you know the current clock > frequency, so you can derive a stable clock for a simple UART. Nope. For normal power saving the entire clock tree is divided by 16 when idle. For full power saving the crystal is powered down. Leo Havm�ller.
From: Ulf Samuelsson on 19 May 2010 17:35 Leo Havm�ller 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 Havm�ller. 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 ;-) -- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
From: Ulf Samuelsson on 19 May 2010 17:36 Leo Havm�ller 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 Havm�ller. 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 ;-) -- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
From: larwe on 19 May 2010 17:42 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.
From: rickman on 19 May 2010 18:27
On May 2, 1:15 am, Leo Havmøller <rtx...(a)nospam.nospam> wrote: > > This sounds like you are creating a chip. You wrote that the clock of the > > chip can change, but I'm sure that the chip has some stable internal clock > > reference, or at least within the chip you know the current clock > > frequency, so you can derive a stable clock for a simple UART. > > Nope. For normal power saving the entire clock tree is divided by 16 when > idle. > For full power saving the crystal is powered down. > > Leo Havmøller. You didn't give the IEEE spec you found. BTW, your original problem has been solved many times before. You need to have some sort of timing reference, but then when the clock is shut down, I would expect the chip is not active either... so I don't think that is a problem. Even if the timing reference varies, the data can be recovered. Think of a signal source where the clocking rate changes during the message. It is something I am sure you see in action nearly every day. Rick |