Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

RS422 to I2C Converter

802 views
Skip to first unread message

ah

unread,
Jun 28, 2003, 5:09:20 AM6/28/03
to
Hi
Im beginning work on a project which I will need a RS422 to I2C Converter.
Has anyone ever done anything like this?

Andy


petrus bitbyter

unread,
Jun 28, 2003, 10:17:23 AM6/28/03
to

"ah" <and...@hanvey82.freeserve.co.uk> schreef in bericht
news:bdjlu0$47i$1...@news6.svr.pol.co.uk...
Andy,

I did. That's to say it was RS232 to I2C. I used a MAX232 and a PIC16F73.
For RS422 you will need differential drivers/receivers p.e. MC3487/86. For
the processor a PIC16F873 may be a better choice as it's newer. You will
need to check what protocol is used at the RS422 side. Is it asynchronous,
SDLC, HDLC or another one? You also need to look wether the I2C side has to
be master, slave or both. Unless you have a proper specification of the
protocol and the data format, you will run into a lot of problems.

pieter


Niv

unread,
Jun 28, 2003, 2:48:54 PM6/28/03
to
I thought RS422 was an electrical protocol & I2C a data format protocol?
Niv.

"ah" <and...@hanvey82.freeserve.co.uk> wrote in message
news:bdjlu0$47i$1...@news6.svr.pol.co.uk...

Gary Tait

unread,
Jun 29, 2003, 10:37:10 AM6/29/03
to
On Sat, 28 Jun 2003 19:48:54 +0100, "Niv" <n...@ntlworld.com> wrote:

>I thought RS422 was an electrical protocol & I2C a data format protocol?
>Niv.
>

It is, hence the need for a two staged process. 1: to convert RS422 to
TTL and the other way round. and 2: to convert the TTL Async to I2C,
in a manner you can access either any I2C device, or a particular one
over the serial link.

Niv

unread,
Jun 30, 2003, 5:02:01 AM6/30/03
to
Yes , that's fine, but you need to know the TTL async protocol to before it
can be converted to I2C protocol. I asume it's a UART type message or
something, but one does need to know!
Niv.

"Gary Tait" <ta...@hurontel.on.ca> wrote in message
news:d7utfvo2r4joarjot...@4ax.com...

simon

unread,
Jul 1, 2003, 7:10:32 AM7/1/03
to
"ah" <and...@hanvey82.freeserve.co.uk> wrote in message news:<bdjlu0$47i$1...@news6.svr.pol.co.uk>...

Checkout the BL233 IC. It is a serial->i2c+spi+1wire convertor chip.
Just add a cheap RS422 transciever chip from STM.

http://www.i2cchip.com/bl233_a.pdf

If you want there is a built up adaptor for RS232/USB->I2C, which has
a connector you can plug the RS422 interface chips into.

Simon

0 new messages