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Need high speed RS232 interconnect

B

Boki

Jan 1, 1970
0
Hi All,

I need a RS232 (PC to embedded device) interconnect/interface that
support 460.8Kbps/921.6Kbps ( higher is better )

Thank you very much!

Best regards,
Boki.
 
B

Boki

Jan 1, 1970
0
Pooh Bear 寫�:
YW.

Graham

In fact, I buy a USB to UART converter yesterday, the title said it
support 1Mbps.. when I installed to PC... it only support 12800Kbps for
maximum...

so, I give up USB.. I try to find PCI. And then I found SUNIX's PCI
RS232 card.

Best regards,
Boki.
 
B

Boki

Jan 1, 1970
0
Boki 寫�:
Pooh Bear 寫�:


In fact, I buy a USB to UART converter yesterday, the title said it
support 1Mbps.. when I installed to PC... it only support 12800Kbps for
maximum...

so, I give up USB.. I try to find PCI. And then I found SUNIX's PCI
RS232 card.

Best regards,
Boki.

ADM3202
 
B

Boki

Jan 1, 1970
0
Pooh Bear 寫�:
Looks fine. Twice as many transceivers as you need but the price makes upfor it. Oh but only 460kbps.

You could use this as 1mbps transmitter.
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2189

And there's a matching receiver.
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2009

But if you're clever you could use some passives to make your own receiver to save cost.

Graham

Thank you very much to consider the cost, but right now, this is for my
development tool only.

and my app needs two way communication....

Best regards,
Boki.
 
J

Jim

Jan 1, 1970
0
Boki said:
Hi All,

I need a RS232 (PC to embedded device) interconnect/interface that
support 460.8Kbps/921.6Kbps ( higher is better )


The FDTI integrated circuits would work for your requirement, although as
I recall, you probably need USB2 on your computer to support the higher
speeds. If you use RS485, this website claims up to 3 MB data rate.
960 KB for RS232 if you want RS232.



http://www.elexol.com/Downloads/USBMOD1DS1.pdf



Jim


--

11:11 Pacific Time Zone
May 29 2006

International Time
18:11 UTC
29.05.2006
 
D

David

Jan 1, 1970
0
Jim said:
The FDTI integrated circuits would work for your requirement, although as
I recall, you probably need USB2 on your computer to support the higher
speeds. If you use RS485, this website claims up to 3 MB data rate.
960 KB for RS232 if you want RS232.

FTDI devices are USB 1.1 (you can connect them to a USB2 port, but they
still only run at 12 MBit). They'll do 1 MB RS-232, or 3 MB RS-485 or
TTL level (i.e., they can do signalling at 3 MB, but RS-232 drivers are
limited to 1 MB).
 
Jim skrev:
The FDTI integrated circuits would work for your requirement, although as
I recall, you probably need USB2 on your computer to support the higher
speeds. If you use RS485, this website claims up to 3 MB data rate.
960 KB for RS232 if you want RS232.

you don't need usb high speed to do 1Mbps.
The FTDI FT232 will do 921.6Kbps but windows won't always let you
configure
a serial port to anything but the <= 115.2kbps standard speeds, so you
have to
go into the driver setup and tell the device to alias one of the
standard speeds to 921.6kbps. That way the device driver will know that
when it is told run at e.g.
300baud it should program the baudrate to 921.6kbps

-Lasse
 
R

Roger Hamlett

Jan 1, 1970
0
Boki said:
Hi All,

I need a RS232 (PC to embedded device) interconnect/interface that
support 460.8Kbps/921.6Kbps ( higher is better )

Thank you very much!

Best regards,
Boki.
Key thing, is that it is unlikely that the embedded device is 'RS232', if
it supports this high a data rate. RS232, is an electrical signalling
spec, _not_ the specification for asynchronous serial data, which the term
is often used (incorrectly) for. I'd strongly suspect that the embedded
device is 'TTL serial', _not_ 'RS232', since this is beyond the specified
rates supported by RS232, and even using extrapolation from the RS232
figures, the cable lengths that would be supported at this rate, would be
tiny.
Hence, making the assumption, that what is needed is actually TTL
asynchronous serial, _not_ 'RS232', then the second question is whether
the device actually supports this rate without handshaking. Few devices an
handle this sort of rate continuously. Now looking at the USB interfaces
that mny posters have mentioned. A lot of such devices support high
interface rates like this, but only on the local interconnection. Most
USB-RS232 adapters, are at heart USB HID devices, and even those
supporting 'high speed' operation, will only achieve 64,000Bps max, and
therefore will have trouble handling a serial bus over 640,000bps. Above
this, they only transfer at these rates for a short moment, till the
buffer is full, and if 'RS232' signalling is used, the maximum cable
lengths are then only a few inches to the device.
Start by saving a lot of effort, and get the data sheet for the 'embedded'
device. If it is yet to be designed, look at a standard like RS422, rather
than RS232. Once you actually have the signalling standard involved, then
there are PCI cards, or block mode USB devices, that can comfortably
handle signalling at these rates. At present, your question is a bit too
'open'. There are hundreds of devices that can operate a serial bus at
these higher rates, but few that can do it for any length of time, and if
the cabling needs to be more than a very few inches long, it is unlikely
that the connection is 'RS232'.

Best Wishes
 
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