rs-485 info/drivers

rs-485 info/drivers

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pharos

Joined: 22 Jul 2002
Posts: 19

26 Jul 2002 6:41 rs-485 info/drivers

Hello All,
I need some good tutorial/notes for RS-485 and any s/w drivers for that. Please help.

Enjoy,

Very Happy

pharos

tom324

Joined: 26 Jun 2001
Posts: 297

26 Jul 2002 9:56

RS-485 is "electrical level" interface. It is half duplex. I assume you are interested in some specific protocol that uses RS485 as interface?

Tom

gabby

Joined: 18 Mar 2002
Posts: 97
Location: Israel

26 Jul 2002 10:29

Hi
You have same companny that make that drivers here some link to the
interface chips datasheet:

1. sipex.
http://www.sipex.com/products/interface.htm

2. linear.
http://www.linear.com/prod/pft.html?product_family=interface

3. national semiconductors.
http://www.national.com/catalog/AnalogInterface.html

4. maxim/dallas.
http://www.maxim-ic.com/Interface.cfm

Best regards. Cool

pharos

Joined: 22 Jul 2002
Posts: 19

26 Jul 2002 11:26

Hello Tom,
I may be wrong, but what i think is that RS-485 is a serial protocol and i need to develop some s/w drivers over that.

Thanks,

pharos

tom324

Joined: 26 Jun 2001
Posts: 297

26 Jul 2002 11:41

pharos wrote:

I may be wrong, but what i think is that RS-485 is a serial protocol and i need to develop some s/w drivers over that.

No, RS485 is not a 'protocol'. Protocol is a set of rules which determine how a connection is established, maintained and terminated. Data exchange is also part of these rules. Protocols are usually implemented by software layer.

Tom

ljmnunes

Joined: 28 Jun 2001
Posts: 28

26 Jul 2002 12:50

hello, pharos.

As tom324 said, RS485 is a hardware interface not a protocol. Some people call it "protocol RS485" but it is not right.

There are a lot of protocol specification in the net. You can only choice that you need.

Can I help you? I used Modbus protocol for years.

TheHungry

Joined: 06 Mar 2002
Posts: 207
Helped: 2

26 Jul 2002 12:58

Shematics and other http://www.bb-elec.com/technical_library.asp?pathid=61

stroma

Joined: 25 Apr 2002
Posts: 114
Helped: 3

26 Jul 2002 16:07

Hi Pharos,
Tom324 is right about RS485 - it is just interface, not a protocol. You probable have to decide which protocol you will implement in software driver(s). I’m using Dallas “1-wire” protocol over RS485 interface to increase distance of the net.
Regards,
stroma

pharos

Joined: 22 Jul 2002
Posts: 19

26 Jul 2002 16:39

Hello guys,
Thanks for the information. Please give me some useful links for RS-485 tutorials. I basically want to implement a serial protocol over RS-485.

regards,

pharos

ted

Joined: 12 Mar 2002
Posts: 118
Helped: 3

26 Jul 2002 17:27

It all depends what is your application. For instance, for instrumentation using serial links (RS232, RS485 +others) you may get ready made software for free at
http://www.windmill.co.uk/rs232.html

You may also find intersting to read
http://www.ece.utexas.edu/~valvano/manual/Lab10.pdf (See also the directory .../manual/ for more documents)
The same professor, Jonathan W. Valvano, has also a software archive (written in C for MC68HC812) containing different things, including a driver for RS-485 networking:
http://www.ece.utexas.edu/~valvano/programs/

Good luck,
Ted

ghbolivar

Joined: 25 Jul 2001
Posts: 109
Helped: 6

28 Jul 2002 4:39

hey! have you already implemented your protocol?
Anyway, i recomend you to take a look at http://www.hth.com
They have created SNAP, a very good protocol. It is open an free:D

jarmestor

Joined: 30 May 2002
Posts: 2

29 Jul 2002 11:53

For RS-485 cabling guidelines, you can view the technical note http://w??.smsc.com/ma?n/anpdf/tn75.p?f

jarmestor Smile

PD:
I think that RS-485 is an electrical specification in many physical layer protocols (bitbus, profibus,....)

7rots51

Joined: 17 May 2002
Posts: 1254
Helped: 14

30 Jul 2002 9:23

hello

you can use modbus protocol for rs485 interface.
www.mo*dicon.com
www.mod*bus.org

you can find c source code on modbus in elektroda.

you can goto www.ad*vantech.com and check their ADAM series ASCII command response protocol,it is very simple but efficient.

mdamdam

Joined: 12 Apr 2002
Posts: 55
Location: the old Europa

31 Jul 2002 15:56

E-Lab have a 9bit network protocol for AVR µC possible but tricky to interface with PC

avra

Joined: 22 Oct 2001
Posts: 24
Location: Serbia

13 Aug 2002 0:40

If you want protocol I use written in E-L-a-b A-V-R-c-o P-A-S-C-A-L, say it. I can also give you windows test software for this protocol.

Avra

Trishool

Joined: 12 Jul 2001
Posts: 81
Location: Himalayas.(mount K2)

23 Sep 2002 23:04 RS485 is a standard !!

pharos wrote:

Hello guys,
Thanks for the information. Please give me some useful links for RS-485 tutorials. I basically want to implement a serial protocol over RS-485.

regards,

pharos

pharos ,

RS485 is a standard , see RS485.com there yo'll find plenty of resource .

Ts

dsp2x

Joined: 02 Mar 2002
Posts: 21

24 Sep 2002 0:36

STOR /RS422 and RS485 Application Note.pdf
550 RS422 and RS485 Application Note.pdf: Cannot create file.
RS422 and RS485 Application Note.pdf: Cannot create file
Failed [RS422 and RS485 Application Note.pdf: Cannot create file]

huahua

Joined: 21 Sep 2002
Posts: 48

27 Sep 2002 6:31

http://www.maxim-ic.com/appnotes.cfm/appnote_number/367

Hope it helps

zohar

Joined: 20 Feb 2002
Posts: 18
Location: Israel

10 Dec 2002 14:09 S.N.A.P Protocol

Hi,
We build an 485 Controller network, after reviewing some major leading industry protocols (such as CAN, TCP, PPP etc.), we found the SNAP as the perfect protocol to controller network. It is a very flexible protocol that can meet ALL MCU application needs from the very smaller resources and up to 16 bits controller end so no.
If you need any help, PM me.

yours,
Zohar

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