Re: PC to RS485 bridge

["Frank Mc Alinden" <fmcalind@xxxxxxxxxxxxxx>]

Hi Neil

> Something needs to turn the pseudo code of
> {
> COMMAND=CLEAR
> TEXT=CURRENT LOUNGE TEMP \n23.12
> DELAY=30

Thats the job for the pc /rs485 application.......Which is going to have to
do a lot of work...I just hope someone has the time to do it .....

Frank


----- Original Message -----
From: "Neil Wrightson" <neilw@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Monday, January 31, 2005 8:53 PM
Subject: Re: [ukha_xpl] PC to RS485 bridge


>
> Hi Frank,
>
> Thanks for the feedback.
>
> Something needs to turn the pseudo code of
> {
> COMMAND=CLEAR
> TEXT=CURRENT LOUNGE TEMP \n23.12
> DELAY=30
> }
> into something that a low level device can under stand.
> Remebering that we are trying to keep the data transfer on the RS485
> bus down and also allow for lower capacity devices to also play a part
> on the 485 bus. So sending -
> COMMAND=CLEAR
> TEXT=CURRENT LOUNGE TEMP \n23.12
> DELAY=30
> on the bus seems a bit heavey and expecting pics etc to have a large
> enough decode area is proably a bit much.
>
> So if the PC wanted to send you above example to a OSD device it would
> send the following command.
> 02   Stx
> 20   Address of OSD deviceBridge is address 0
> ??   Length of message
> 'C'  xpl-status  C=Remote command to be sent to a slave device
> XXX  07H,'CURRENT LOUNGE TEMP',0DH,1EH,'23.12',0DH,0F
> xx   Checksum
> 03    ETX
>
> The xxx equeats to Clear screen,write text,CR,delay for this line,
text
> on next line,CR,delay for this line.
> In the On Screen Devices I have developed, I actually use ClearScrean
&
> GotoXY commands. This allows the PC to do the screen or line clearing
> or clearing of three characters at a certain XY location
>
>
> Neil.
>
>
>
>
> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
http://www.xpl.myby.co.uk
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