Asyncronous 1-wire interface?
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From: -jg on 29 Apr 2010 22:22 On Apr 29, 8:39 pm, Leo Havmøller > > Yes, it even has a crystal ;-) > Due to power saving the clocks are changed up and down all the time => no > fixed clock is available. We still do not know the baud rate, message sizes and average data rates you are looking for. If you have just one wire, you have the time-domain, and the voltage domain to chose from. Most systems use the time-domain, because that is simplest, and many systems are clock tolerant. Some schemes can work with nothing more complex than a monostable - a RC element. Just how power/energy paranoid is this application, and how much power does that crystal you have consume ? If you have a crystal, is it running all the time ? -jg
From: Neil on 1 May 2010 00:40 On 4/29/2010 7:59 AM, Leo Havm�ller wrote: > > "Nial Stewart" <nial*REMOVE_THIS*@nialstewartdevelopments.co.uk> wrote > in message news:83t9o5F686U1(a)mid.individual.net... >> "Leo Havm�ller" <rtxleh(a)nospam.nospam> wrote in message >> news:hrb32b$tm1$1(a)speranza.aioe.org... >>> Hi, >>> Im looking for a short-range (20 cm) 1-wire I/O interface that is >>> fully asyncronous. >>> Does such a thing exist? >> >> http://www.1pin-interface.com >> >> This transfers data from the module to the PC at 1Mbps and is pretty >> robust. > > Also locked to a specific baudrate, so does not fit the requirements. > > Leo Havm�ller. You could try DQ or HDQ. It still needs a stable clock the data is transmitted in the pulse width.
From: Leo Havmøller on 1 May 2010 01:07 "Leo Havm�ller" <rtxleh(a)nospam.nospam> skrev i meddelelsen news:hrb32b$tm1$1(a)speranza.aioe.org... > Hi, > > Im looking for a short-range (20 cm) 1-wire I/O interface that is fully > asyncronous. > Does such a thing exist? By pure coincidence, an unrelated event led med to a brand new IEEE standard for the interface needed. It is using 2 wires (1 clock and 1 I/O). The chip vendor has accepted that this is the way to go. Case closed. Leo Havm�ller.
From: Leo Havmøller on 1 May 2010 01:09 > OK, I'll ask...why 1 wire? Cost. As a rule of thumb, each pin on a chip is 1 cent. Leo Havm�ller.
From: Frank Buss on 1 May 2010 03:11
Leo Havm�ller wrote: > By pure coincidence, an unrelated event led med to a brand new IEEE standard > for the interface needed. It is using 2 wires (1 clock and 1 I/O). Could you write which IEEE standard you'll use? There are many two-wire protocols, a standard would be useful when I need it. > The chip vendor has accepted that this is the way to go. Case closed. 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. -- Frank Buss, fb(a)frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de |