top baud for BS2SX

Archiver

Does anyone know what the top baud rate would be for a BS2SX? The
manual has asterix on 4800 and 9600 parameters and warnings that
there might be communication problems. I just want a short haul to a
CMUcam and I'm wondering if I can run 38400 on a direct TTL set up.
Thanks in advance


Steve

Archiver

> Does anyone know what the top baud rate would be for a BS2SX? The
>manual has asterix on 4800 and 9600 parameters and warnings that
>there might be communication problems. I just want a short haul to a
>CMUcam and I'm wondering if I can run 38400 on a direct TTL set up.
> Thanks in advance
>
>Steve


Hi Steve,

The highest baud rate for the 'SX is theoretically 125 kbaud when the
baudmode parameter is zero. You should have no trouble achieving
38.4.

I think the business in the manual about communications problems is a
bit misleading. The difficulties they speak of come about mainly
when you are trying to receive data from external devices over which
you have no control, and which are spitting out long strings of data
at a high baud rate with no extra inter-byte padding beyond the
standard 1 stop bit. The SERIN command modifiers like DEC or WAIT or
SKIP take some time to interpret in the Stamp, and it is likely to
miscue and garble the incoming message. Also, the hardware flow
control on the Stamp works byte by byte, and some external devices,
even though they implement some kind of hardware flow control, do so
on a buffer that may send several bytes before the flow control is
recognized. If you do in fact have control over both ends of the
communication, or you can be sure that there is a little extra
breathing room between the bytes, you can push the Stamp almost to
its limit. At the very limit on the SX, 125 kbaud, the bit timing
will be dicey, but there should not be much problem at 38.4 with
individual bytes.

-- Tracy
http://www.emesystems.com/BS2rs232.htm#Baudmode <-- table of baud rates

Archiver

What would the top baud rate be for a BS2. I am doing a project that needs
to talk to a serial port at 38400, I don't need to receive anything back
just send some hex values similar to the earlier discussion to control a
Sony projector. Thanks in advance for any answers. matt


At 10:47 AM 11/7/2003 -0800, you wrote:
> > Does anyone know what the top baud rate would be for a BS2SX? The
> >manual has asterix on 4800 and 9600 parameters and warnings that
> >there might be communication problems. I just want a short haul to a
> >CMUcam and I'm wondering if I can run 38400 on a direct TTL set up.
> > Thanks in advance
> >
> >Steve
>
>
>Hi Steve,
>
>The highest baud rate for the 'SX is theoretically 125 kbaud when the
>baudmode parameter is zero. You should have no trouble achieving
>38.4.
>
>I think the business in the manual about communications problems is a
>bit misleading. The difficulties they speak of come about mainly
>when you are trying to receive data from external devices over which
>you have no control, and which are spitting out long strings of data
>at a high baud rate with no extra inter-byte padding beyond the
>standard 1 stop bit. The SERIN command modifiers like DEC or WAIT or
>SKIP take some time to interpret in the Stamp, and it is likely to
>miscue and garble the incoming message. Also, the hardware flow
>control on the Stamp works byte by byte, and some external devices,
>even though they implement some kind of hardware flow control, do so
>on a buffer that may send several bytes before the flow control is
>recognized. If you do in fact have control over both ends of the
>communication, or you can be sure that there is a little extra
>breathing room between the bytes, you can push the Stamp almost to
>its limit. At the very limit on the SX, 125 kbaud, the bit timing
>will be dicey, but there should not be much problem at 38.4 with
>individual bytes.
>
> -- Tracy
> http://www.emesystems.com/BS2rs232.htm#Baudmode <-- table of baud rates
>
>
>
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Matt Seniff
Principle Electronic Technician
Classroom Technology Support Services
Illinois State University
PH 309-438-7734
FAX 309-438-3623