Linux RS485 HA Network with PIC microcontroller
Hardi Gunawan
website defining RS-485 protocol. Also, I'm not quite familiar with
Linux serial port programming.
I've read somewhere that if I use a RS-232 to RS-485 converter with a
microcontroller inside it, there's no need to do a low level
programming in Linux. Is that true? Where can I get such circuit?
If not, where can I find a converter circuit complete with linux's
driver?
Dave Houston
>Hi, I would like to automate my home with RS485. I can't find any
>website defining RS-485 protocol. Also, I'm not quite familiar with
>Linux serial port programming.
RS-485 is an electrical specification, not a communications protocol you'll
have to devise your own communications protocol. B&B Electronics has an
excellent online RS-485 tutorial at...
http://www.bb-elec.com/tech_articles/rs422_485_app_note/table_of_contents.asp
>I've read somewhere that if I use a RS-232 to RS-485 converter with a
>microcontroller inside it, there's no need to do a low level
>programming in Linux. Is that true? Where can I get such circuit?
>If not, where can I find a converter circuit complete with linux's
>driver?
B&B also sells RS-232 to RS-485 converters.
---
http://www.laser.com/dhouston/
Neil Cherry
try:
Net 9 - http://rs485.de-franek.de/
Ulan Driver - http://cmp.felk.cvut.cz/~pisa/ulan/ul_drv.html
BITBUS Library - http://www.andrive.de/andreas/
There was one more, it was Steve Rodger's HANd project, but since
@Home died I don't know where it is (more links to fix).
--
Linux Home Automation Neil Cherry nch...@comcast.net
http://mywebpages.comcast.net/ncherry/ (Text only)
http://linuxha.sourceforge.net/ (SourceForge)
http://hcs.sourceforge.net/ (HCS II)
Guy Lavoie
methodology. By definition, RS485 is half duplex, so you need to either
know when you can transmit (bus arbitration ususally implemented by
"polling") or implement a collision detection scheme, which can be a lot
of work. The RS485 to RS232 converters usually use one of the control
lines (like carrier detect) to turn on the transmitter, so you still need
to be timing aware in your application.
