First of all, could the Series 1 module simply wired up to a RS-485 transceiver chip? If possible, is there any reference design for reference?
Secondly, which firmware is good for this Wireless RS485 application? 1084 or other?
The simple solution as far as I can see is to buy one of the adaptors that are available, eg from Digi. Type “xbee rs-485” into Google to find a few. But if by “simple” you also meant “cheap”, I wouldn’t know the answer.
For the firmware, I’ve not yet seen anything that would make it an advantage to use anything but the latest. The latest simply has more features, which means you have more options in your design. To get an idea, take a look through the product manual and see how many features are marked as “introduced in version xxxx”.
If 1084 does have enough features for you, then fair enough. But the upgrade is easy if you have a development kit, so there seems little reason not to do it.
Thanks for your feedback. I am aware that they are some adaptors from Digi and other. What I am doing now is trying to interconnect my XBee Pro module to a SN75716 RS-485 transceiver with no CPU around.
Problem are with the /RTS on the module as a 2-wire RS-485 doesn’t have any flow control pin. Is it really necessary to have a CPU to handle the flow control? or I can get around using some sort of logic circuitry?
To use correctly the SN75716 RS485 interface chip I need to manage the /RTS signals (Request To Send) to enable the TX section (DE pin3 on SN75716) only when data are transmitted on TXD line (Transmit Data) as my attached figure.
I was just browsing through the articles in the knowledge base, and I found this:
http://www.digi.com/support/kbase/kbaseresultdetl.jsp?id=2034
Subject line is “Convert SPKG interface board from RS-232 to RS-485/422”.
It relates (I think) to an older interface board, and I don’t know whether it would help with this query. Seemed worth mentioning, though.