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Solaris2001
Siedler
24 Beiträge
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Connecting Display to AVR., 03 Jul. 2014 17:26
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Hi! In my transport company there a few LAWO‘s displays.
I wanted to control them by AVR-kit.
I have a RS-485 module and RS485-RS232 convert module.
As far as I know the German Displays works in IBIS.
So is it possible to connect display to RS485 and send orders by terminal to it?
Does anybody have scheme?
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Thijs van de Bles
Gelehrter
120 Beiträge
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RE: Connecting Display to AVR., 04 Jul. 2014 09:11
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The easyist way to do this is to make TTL from rs232 (on ebay there are cheap circuits for sale) and then boost the TTL from 5 volt to 21 volt. Then you have IBIS.
But: This is not short-circuit proof! You can blow up youre rs232 port.
There are proffesional rs485 / IBIS modems on the market, but very expensive.
On this forum are several circuits to find. So dust of youre solder iron, and crack it up.
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xd19@o2.pl
Siedler
49 Beiträge
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RE: Connecting Display to AVR., 04 Jul. 2014 21:00
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Actually UART/USARTs on AVR are already these TTLs (on 3V3 or 5V, depending on the model), so you don‘t need to convert anything to RS232 or 485, I guess that to have output you have to connect the TX output via opto-transistor, something like that should work
http://imgur.com/JUCHjhI
However I don‘t know how to correctly and safely connect the input to an uC
Geändert von xd19@o2.pl am 15.Jul.2014 21:55
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Thijs van de Bles
Gelehrter
120 Beiträge
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RE: Connecting Display to AVR., 05 Jul. 2014 17:45
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That will do the trick for TX.
With an opto-coupler you atleast have a electrical divider.
For RX you can use a shotkey zener-diode.
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Solaris2001
Siedler
24 Beiträge
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RE: Connecting Display to AVR., 06 Jul. 2014 14:30
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Thanks for yours replies :) !
I think that the easiest way is to remove orginal driver and replace it with my own programmed uC.
In my transport company all displays works on polish R&G system.
It‘s very easy to use and easy to program.
The autocomputer send information to display about route number and direction.
The display generate a bitmap itself.
Unfortunately LAWO‘s displays require a special software to change the directions.
But, Can I program a directions without special software? Is it easy?
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Grzegory
Adeliger
255 Beiträge
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RE: Connecting Display to AVR., 27 Aug. 2014 12:53
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Napisz do mnie znam się na tym
speacetronic@neostrada.pl
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