Hey evryOne!
How about wiegand protocol? Did some search with my
web archive engine and there is lot of info available out there;-) But
I could not understand how a MCU and RS232 can communicate over this
protocol? I mean that there are tow data lines representing '0' and
'1' in wiegand, where as normally dealing with RS232 we use MAX232
line driver's tow pins that are Rx, and TX for receiving and
transmitting respectively. Though there are extra tow Rx and Tx
available on line driver (MAX232) but still can't figure out how to
do that? And finally is it that worthy (fast) then direct UART or SPI?
Hey! Is there any thing that Intel guys have developed for
communication over a single line? heard from some one but don't kow
about that;-)
ali
wiegand protocol
Started by ●September 9, 2006
Reply by ●September 10, 20062006-09-10
"Ali" <abdulrazaq@gmail.com> wrote in message news:1157795335.512170.81730@p79g2000cwp.googlegroups.com...> Hey evryOne! > > How about wiegand protocol? Did some search with my > web archive engine and there is lot of info available out there;-) But > I could not understand how a MCU and RS232 can communicate over this > protocol? I mean that there are tow data lines representing '0' and > '1' in wiegand, where as normally dealing with RS232 we use MAX232 > line driver's tow pins that are Rx, and TX for receiving and > transmitting respectively. Though there are extra tow Rx and Tx > available on line driver (MAX232) but still can't figure out how to > do that? And finally is it that worthy (fast) then direct UART or SPI? > > Hey! Is there any thing that Intel guys have developed for > communication over a single line? heard from some one but don't kow > about that;-) > > > ali >Yeah, how about it! Weigand is a primitive TTL level protocol that no one in their right mind would use unless they needed to communicate with Weigand devices. These are commonly used in the security and access control industries. A MAX232 would not normally play a part in a weigand interface. It would be as superfluous as mammary glands on a male bovine. Weigand is a slow protocol (500 baud), certainly not comparable to most UART or SPI interfaces. I believe that Intel has recently invented the 2CANbus, comprising accoustically coupled FeSn communications diaphragms within cylindrical resonating chambers, coupled by a single line. Be prepared for this to play a major role in pre-pubescent espionage and counter-espionage simulations in the near future. Cheers, Alf.
Reply by ●September 10, 20062006-09-10
Alf Katz wrote:>... snip ...> > I believe that Intel has recently invented the 2CANbus, comprising > accoustically coupled FeSn communications diaphragms within > cylindrical resonating chambers, coupled by a single line. Be > prepared for this to play a major role in pre-pubescent espionage > and counter-espionage simulations in the near future.However there are major problems with that bus, having to do with the physical makeup of the line and its tensile strength. The bus length is strictly limited, and must use line-of-sight. Bandwidth is also a problem. Protocols for its use are nebulous. -- Chuck F (cbfalconer at maineline dot net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net> -- Posted via a free Usenet account from http://www.teranews.com Warning: Do not use Ultimate-Anonymity They are worthless spamers that are running a scam.
Reply by ●September 10, 20062006-09-10
Ali wrote:> Hey evryOne! > > How about wiegand protocol? Did some search with my > web archive engine and there is lot of info available out there;-) But > I could not understand how a MCU and RS232 can communicate over this > protocol? I mean that there are tow data lines representing '0' and > '1' in wiegand, where as normally dealing with RS232 we use MAX232 > line driver's tow pins that are Rx, and TX for receiving and > transmitting respectively. Though there are extra tow Rx and Tx > available on line driver (MAX232) but still can't figure out how to > do that? And finally is it that worthy (fast) then direct UART or SPI? >The Wiegand output signals Data0 and Data1 are usually open-collector and can tolerate a voltage up to 15V or more. You could use an RS-232 level-shifter, such as the MAX232 to get logic level signals your uC could deal with, even though the Wiegand signals never go below 0V. Your code would have to catch every negative spike on the Data0 and Data1 lines and shift an appropriate bit ('0' or '1') into a virtual shift register. The easiest way to do this is to connect the level-shifted Data0 and Data1 signals to two interrupt pins of your uC. There are several Wiegand formats, differing in the number of bits, type of parity checking etc. I think that only the 27 bit variant is documented, all the longer ones being proprietary. Try searching HID and Motorola sites for the exact format.
Reply by ●September 11, 20062006-09-11
Hi Ali, My limited understanding is as follow... Early Wiegand ISO cards had 2 rows embedded in to a card. Each row had a tiny strips of metal placed along the card.. One row was logic '1' and the other row was for '0'. Like this '0''s I I I I '1''s I I I I I I So the logic sequence from left to right would be 0110110110 So when you swiped the card accorss the reader this is the logic sequemce that is picked up. See page 3 of this web link http://www.cdvamericas.com/PDF%20ENGLISH%20MANUALS/DGLI-DGLP-wiegand-MAN-DEC05.pdf#search=%22Wiegand%20signals%22 So typically a micro monitors signals on the '0' data line and the '1' data line.... So You will need to use a micro or similar as a "bridge" to convert the non-popular Wiegand to UART-RS232. Typically the physically layer is "open-collector" / "open drain" with pull ups.... Regards Joseph Goldburg "Ali" <abdulrazaq@gmail.com> wrote in message news:1157795335.512170.81730@p79g2000cwp.googlegroups.com...> Hey evryOne! > > How about wiegand protocol? Did some search with my > web archive engine and there is lot of info available out there;-) But > I could not understand how a MCU and RS232 can communicate over this > protocol? I mean that there are tow data lines representing '0' and > '1' in wiegand, where as normally dealing with RS232 we use MAX232 > line driver's tow pins that are Rx, and TX for receiving and > transmitting respectively. Though there are extra tow Rx and Tx > available on line driver (MAX232) but still can't figure out how to > do that? And finally is it that worthy (fast) then direct UART or SPI? > > Hey! Is there any thing that Intel guys have developed for > communication over a single line? heard from some one but don't kow > about that;-) > > > ali >
Reply by ●September 11, 20062006-09-11
Joe G (Home) wrote:> Hi Ali, > > My limited understanding is as follow... > > Early Wiegand ISO cards had 2 rows embedded in to a card. > > Each row had a tiny strips of metal placed along the card.. > > One row was logic '1' and the other row was for '0'. > > Like this > > > '0''s I I I I > '1''s I I I I I I > > > So the logic sequence from left to right would be 0110110110 > > So when you swiped the card accorss the reader this is the logic sequemce > that is picked up. > > See page 3 of this web link > http://www.cdvamericas.com/PDF%20ENGLISH%20MANUALS/DGLI-DGLP-wiegand-MAN-DEC05.pdf#search=%22Wiegand%20signals%22 > > > So typically a micro monitors signals on the '0' data line and the '1' data > line.... > > So You will need to use a micro or similar as a "bridge" to convert the > non-popular Wiegand to UART-RS232. > > > Typically the physically layer is "open-collector" / "open drain" with pull > ups.... > > > Regards > Joseph Goldburg > > > "Ali" <abdulrazaq@gmail.com> wrote in message > news:1157795335.512170.81730@p79g2000cwp.googlegroups.com... > > Hey evryOne! > > > > How about wiegand protocol? Did some search with my > > web archive engine and there is lot of info available out there;-) But > > I could not understand how a MCU and RS232 can communicate over this > > protocol? I mean that there are tow data lines representing '0' and > > '1' in wiegand, where as normally dealing with RS232 we use MAX232 > > line driver's tow pins that are Rx, and TX for receiving and > > transmitting respectively. Though there are extra tow Rx and Tx > > available on line driver (MAX232) but still can't figure out how to > > do that? And finally is it that worthy (fast) then direct UART or SPI? > > > > Hey! Is there any thing that Intel guys have developed for > > communication over a single line? heard from some one but don't kow > > about that;-) > > > > > > ali > >Thanks every body. Yes, things are quite clear now, for example MCU might be listening on tow external interrupts for falling(DATA0) and rising(DATA1) edges. Then it packs the data in either 26 or 44 format, and finally pushing it to host (RS232, MCU etc..). I have observed that weigand is widely used in access control systems but really can't understand why weigand? As few folks in this thread have also pointed that its not that fast so what is the key benefit of weigand in access control systems? Say i have a reader and MCU, reader will output the data in linear way , right? so that does not make any difference if i use tow interrupts or one to decode incoming signal because it will never overlap. I might be wrong but do you people think that this approach (weigand) in RFID readers can improve the performance? ali
Reply by ●September 12, 20062006-09-12
Ali wrote:> Joe G (Home) wrote: >> Hi Ali, >> >> My limited understanding is as follow... >> >> Early Wiegand ISO cards had 2 rows embedded in to a card. >> >> Each row had a tiny strips of metal placed along the card.. >> >> One row was logic '1' and the other row was for '0'. >> >> Like this >> >> >> '0''s I I I I >> '1''s I I I I I I >> >> >> So the logic sequence from left to right would be 0110110110 >> >> So when you swiped the card accorss the reader this is the logic sequemce >> that is picked up. >> >> See page 3 of this web link >> http://www.cdvamericas.com/PDF%20ENGLISH%20MANUALS/DGLI-DGLP-wiegand-MAN-DEC05.pdf#search=%22Wiegand%20signals%22 >> >> >> So typically a micro monitors signals on the '0' data line and the '1' data >> line.... >> >> So You will need to use a micro or similar as a "bridge" to convert the >> non-popular Wiegand to UART-RS232. >> >> >> Typically the physically layer is "open-collector" / "open drain" with pull >> ups.... >> >> >> Regards >> Joseph Goldburg >> >> >> "Ali" <abdulrazaq@gmail.com> wrote in message >> news:1157795335.512170.81730@p79g2000cwp.googlegroups.com... >>> Hey evryOne! >>> >>> How about wiegand protocol? Did some search with my >>> web archive engine and there is lot of info available out there;-) But >>> I could not understand how a MCU and RS232 can communicate over this >>> protocol? I mean that there are tow data lines representing '0' and >>> '1' in wiegand, where as normally dealing with RS232 we use MAX232 >>> line driver's tow pins that are Rx, and TX for receiving and >>> transmitting respectively. Though there are extra tow Rx and Tx >>> available on line driver (MAX232) but still can't figure out how to >>> do that? And finally is it that worthy (fast) then direct UART or SPI? >>> >>> Hey! Is there any thing that Intel guys have developed for >>> communication over a single line? heard from some one but don't kow >>> about that;-) >>> >>> >>> ali >>> > > > Thanks every body. Yes, things are quite clear now, for example MCU > might be listening on tow external interrupts for falling(DATA0) and > rising(DATA1) edges. Then it packs the data in either 26 or 44 format, > and finally pushing it to host (RS232, MCU etc..). > > I have observed that weigand is widely used in access control systems > but really can't understand why weigand? As few folks in this thread > have also pointed that its not that fast so what is the key benefit of > weigand in access control systems? > > Say i have a reader and MCU, reader will output the data in linear way > , right? so that does not make any difference if i use tow interrupts > or one to decode incoming signal because it will never overlap. > I might be wrong but do you people think that this approach (weigand) > in RFID readers can improve the performance? >One great strength of Weigand is that it is speed-independent. With ordinary UART-talk, for example, the parties must agree on a given data rate. Usually, that's no problem. But if the data source is a hand-swiped card, the bit-rate off the card can be anything. To pass that to a UART will require some buffering. That added majorly to the cost, back in the 1970's.
Reply by ●September 12, 20062006-09-12
David R Brooks wrote:> Ali wrote: > > Joe G (Home) wrote: > >> Hi Ali, > >> > >> My limited understanding is as follow... > >> > >> Early Wiegand ISO cards had 2 rows embedded in to a card. > >> > >> Each row had a tiny strips of metal placed along the card.. > >> > >> One row was logic '1' and the other row was for '0'. > >> > >> Like this > >> > >> > >> '0''s I I I I > >> '1''s I I I I I I > >> > >> > >> So the logic sequence from left to right would be 0110110110 > >> > >> So when you swiped the card accorss the reader this is the logic sequemce > >> that is picked up. > >> > >> See page 3 of this web link > >> http://www.cdvamericas.com/PDF%20ENGLISH%20MANUALS/DGLI-DGLP-wiegand-MAN-DEC05.pdf#search=%22Wiegand%20signals%22 > >> > >> > >> So typically a micro monitors signals on the '0' data line and the '1' data > >> line.... > >> > >> So You will need to use a micro or similar as a "bridge" to convert the > >> non-popular Wiegand to UART-RS232. > >> > >> > >> Typically the physically layer is "open-collector" / "open drain" with pull > >> ups.... > >> > >> > >> Regards > >> Joseph Goldburg > >> > >> > >> "Ali" <abdulrazaq@gmail.com> wrote in message > >> news:1157795335.512170.81730@p79g2000cwp.googlegroups.com... > >>> Hey evryOne! > >>> > >>> How about wiegand protocol? Did some search with my > >>> web archive engine and there is lot of info available out there;-) But > >>> I could not understand how a MCU and RS232 can communicate over this > >>> protocol? I mean that there are tow data lines representing '0' and > >>> '1' in wiegand, where as normally dealing with RS232 we use MAX232 > >>> line driver's tow pins that are Rx, and TX for receiving and > >>> transmitting respectively. Though there are extra tow Rx and Tx > >>> available on line driver (MAX232) but still can't figure out how to > >>> do that? And finally is it that worthy (fast) then direct UART or SPI? > >>> > >>> Hey! Is there any thing that Intel guys have developed for > >>> communication over a single line? heard from some one but don't kow > >>> about that;-) > >>> > >>> > >>> ali > >>> > > > > > > Thanks every body. Yes, things are quite clear now, for example MCU > > might be listening on tow external interrupts for falling(DATA0) and > > rising(DATA1) edges. Then it packs the data in either 26 or 44 format, > > and finally pushing it to host (RS232, MCU etc..). > > > > I have observed that weigand is widely used in access control systems > > but really can't understand why weigand? As few folks in this thread > > have also pointed that its not that fast so what is the key benefit of > > weigand in access control systems? > > > > Say i have a reader and MCU, reader will output the data in linear way > > , right? so that does not make any difference if i use tow interrupts > > or one to decode incoming signal because it will never overlap. > > I might be wrong but do you people think that this approach (weigand) > > in RFID readers can improve the performance? > > > One great strength of Weigand is that it is speed-independent. With > ordinary UART-talk, for example, the parties must agree on a given data > rate. Usually, that's no problem. > But if the data source is a hand-swiped card, the bit-rate off the card > can be anything. To pass that to a UART will require some buffering. > That added majorly to the cost, back in the 1970's.>To pass that to a UART will require some buffering.So the bottomline is not to use weigand if UART is way down in communication link , right? ali
Reply by ●September 12, 20062006-09-12
> So the bottomline is not to use weigand if UART is way down in > communication link , right? >You have to use Wiegand: a) If you are making an access-control or time-attendance unit and will not be making the readers yourself. Chances are you will find the largest selection of card readers, keypads etc. with Wiegand outputs. Having Wiegand inputs on your controller is thus a good idea. b) If you want to make a card reader, keypad etc. for use by other people's controller boards. Since most of them provide Wiegand inputs (for reasons stated in a), your readers will connect easily to their boards. This closed loop is the reason why there are even fingerprint readers with Wiegand outputs!
Reply by ●September 12, 20062006-09-12
"Viktor" <vkesler@gmail.com> wrote in message news:1158081078.097918.215770@b28g2000cwb.googlegroups.com...> > So the bottomline is not to use weigand if UART is way down in > > communication link , right? > > > > You have to use Wiegand: > > a) If you are making an access-control or time-attendance unit and will > not be making the readers yourself. Chances are you will find the > largest selection of card readers, keypads etc. with Wiegand outputs. > Having Wiegand inputs on your controller is thus a good idea.Is that still true? In my experience with cardreaders and access control systems (in Europ, that is) most systems have an Omron interface as common denominator, which has a data, clock and cls (Card Load Signal) signal. Meindert
