--- In mike ingle <> wrote:
>
> Hi all,
>
> I need to maintain communications with 80 devices overRS-232 serial (115k).
> Each device streams an approximately 120 byte packet every 100ms.
> also the host, can send packets, and expect a response at any time. The
> packets are hex encoded with out of band start and stop characters.
>
> I am contemplating using 10 ts-7550s (with appropriate level shifters) to
> control the devices, and forward the data over ethernet. The intent would be
> to crack the serial packets (which include 2 crc32 checks) down to their
> 60byte binary size, buffer 10 or so serial packets per channel, (600bytes
> per ethernet packet) and send them on up to a host for logging and display.
>
> My data rate calculations show very modest ethernet usage (8 x 600 bytes/s).
>
> On the surface the ts-7550 looks like a nice fit for this. Anyone have any
> experience with the XUARTs , or better suggestions? Probably no more than 3
> <80 channel systems> will be built.
>
> Best Regards Mike
>
If you can get away with talking to only one or a subset of uarts at a time,
and
Assuming that the data packets result in a low bandwidth for the 100ms window,
you could also use 4-7 DO bit as a switch selector to select 16-128 different
RS232 ports using a few transistors. you will use only 1-3 of the uarts on the
ts-7550, but it will break out to 128 different RS232 ports. using the same
DO bits and more transistors on the outbound side, you can also funnel the comm
to only one set of level shifters and then direct the up-shifted data to the
correct DB9 RS232 port.
You'll end up with using many less ts-7550's.
depending on the bandwidth and need for simutanious comm, you can do in theory
128 rs232 ports with one ts-7550 using one comm port and 7 DO pins.
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