Paul Keinanen wrote:
> On Tue, 1 Sep 2009 09:40:24 -0600, "Not Really Me"
> <scott@validatedQWERTYsoftware.XYZZY.com> wrote:
>
>
>> Look up radioteletype on Wikipedia and you will see that 5-bit is
>> still in use.
>
> While some radio amateurs might still use RTTY with 170 Hz frequency
> shift for historical reasons, most radio amateurs prefer PSK31 or
> similar more spectrally efficient modes for real time keyboard to
> keyboard communication.
>
> Paul OH3LWR

Who said "amateurs"?

ArarghMail908NOSPAM@NOT.AT.Arargh.com wrote:
> On Tue, 1 Sep 2009 09:40:24 -0600, "Not Really Me"
> <scott@validatedQWERTYsoftware.XYZZY.com> wrote:
>
>> HT-Lab wrote:
>>> Hi all,
>>>
>>> I just wrote a simple driver for a 16750 UART and wondered if there
>>> are still (embedded) systems that use the 5 and 6 bits character
>>> length format?
>>> A quick google search showed that 5 bits/1.5 stopbits were used for
>>> old mechanical teletypes, not sure what 6 bits are used for.
>>>
>>> I assume these formats are no longer used but I might be wrong,
>>>
>>> Thanks
>>> Hans
>>> www.ht-lab.com
>>
>> Putting on my "Dilbert dinosaur suit", I did an embedded 5 bit
>> interface in the mid 80's.  The task was to make a baudot (5-bit)
>> converter for an early HP inkjet printer that had ASCII (7/8-bit)
>> serial and parallel interfaces. Done with a TI TMS7000 processor.
> You could almost do that with a UART, a ROM, and a little glue logic?
>
Or an FPGA, or...   Certainly lot's of solutions.  At the time this was in a 
$500 printer that was "modified" and resold for about $7000.   The chosen 
path was speed of implementation, although I can't remember why we chose 
that processor.  Was not in the main stream of what we typically used.

Scott 

On Tue, 1 Sep 2009 09:40:24 -0600, "Not Really Me"
<scott@validatedQWERTYsoftware.XYZZY.com> wrote:


>Look up radioteletype on Wikipedia and you will see that 5-bit is still in 
>use.

While some radio amateurs might still use RTTY with 170 Hz frequency
shift for historical reasons, most radio amateurs prefer PSK31 or
similar more spectrally efficient modes for real time keyboard to
keyboard communication.

Paul OH3LWR

On Tue, 1 Sep 2009 09:40:24 -0600, "Not Really Me"
<scott@validatedQWERTYsoftware.XYZZY.com> wrote:

>HT-Lab wrote:
>> Hi all,
>>
>> I just wrote a simple driver for a 16750 UART and wondered if there
>> are still (embedded) systems that use the 5 and 6 bits character
>> length format?
>> A quick google search showed that 5 bits/1.5 stopbits were used for
>> old mechanical teletypes, not sure what 6 bits are used for.
>>
>> I assume these formats are no longer used but I might be wrong,
>>
>> Thanks
>> Hans
>> www.ht-lab.com
>
>Putting on my "Dilbert dinosaur suit", I did an embedded 5 bit interface in 
>the mid 80's.  The task was to make a baudot (5-bit) converter for an early 
>HP inkjet printer that had ASCII (7/8-bit) serial and parallel interfaces. 
>Done with a TI TMS7000 processor.
You could almost do that with a UART, a ROM, and a little glue logic?


>Look up radioteletype on Wikipedia and you will see that 5-bit is still in 
>use.
-- 
ArarghMail908 at [drop the 'http://www.' from ->] http://www.arargh.com
BCET Basic Compiler Page: http://www.arargh.com/basic/index.html

To reply by email, remove the extra stuff from the reply address.

HT-Lab wrote:
> Hi all,
>
> I just wrote a simple driver for a 16750 UART and wondered if there
> are still (embedded) systems that use the 5 and 6 bits character
> length format?
> A quick google search showed that 5 bits/1.5 stopbits were used for
> old mechanical teletypes, not sure what 6 bits are used for.
>
> I assume these formats are no longer used but I might be wrong,
>
> Thanks
> Hans
> www.ht-lab.com

Putting on my "Dilbert dinosaur suit", I did an embedded 5 bit interface in 
the mid 80's.  The task was to make a baudot (5-bit) converter for an early 
HP inkjet printer that had ASCII (7/8-bit) serial and parallel interfaces. 
Done with a TI TMS7000 processor.

Look up radioteletype on Wikipedia and you will see that 5-bit is still in 
use.

Scott

>Thanks for all the replies, very helpful,
>
>Hans
>www.ht-lab.com
>
>
>
Oddly enough, I just ran across an application that requires 6 bit
characters.  It is an old Brown Boveri protocol from the 70's.  Are you
developing your driver as a commercial product?  

Thanks for all the replies, very helpful,

Hans
www.ht-lab.com

On Thu, 27 Aug 2009 22:27:06 +0300, Paul Keinanen <keinanen@sci.fi>
wrote:

>On Thu, 27 Aug 2009 11:16:05 +0100, "HT-Lab" <hans64@ht-lab.com>
>wrote:
>
>>Hi all,
>>
>>I just wrote a simple driver for a 16750 UART and wondered if there are still 
>>(embedded) systems that use the 5 and 6 bits character length format?
>>
>>A quick google search showed that 5 bits/1.5 stopbits were used for old 
>>mechanical teletypes, not sure what 6 bits are used for.
>
>5 data bits + 1.5 stop bits might still be used in some radio amateur
>radio Teletype (RTTY) communication systems.
>
>6 data bits was common with 36 bit computers (Univac etc.), with (6
>bits/char), but I have not seen 6 bit chars in serial communication
>for more than three decades.

Cripes.  I'd forgotten about 36-bit.  PDP-10 comes to mind, now.  But
they packed them as 7-bit by then, as I recall, so a 36-bit word gave
you 5 characters (plus a little.)

Jon

On Thu, 27 Aug 2009 11:16:05 +0100, "HT-Lab" <hans64@ht-lab.com>
wrote:

>Hi all,
>
>I just wrote a simple driver for a 16750 UART and wondered if there are still 
>(embedded) systems that use the 5 and 6 bits character length format?
>
>A quick google search showed that 5 bits/1.5 stopbits were used for old 
>mechanical teletypes, not sure what 6 bits are used for.

5 data bits + 1.5 stop bits might still be used in some radio amateur
radio Teletype (RTTY) communication systems.

6 data bits was common with 36 bit computers (Univac etc.), with (6
bits/char), but I have not seen 6 bit chars in serial communication
for more than three decades.

Paul

On Thu, 27 Aug 2009 11:16:05 +0100, "HT-Lab" <hans64@ht-lab.com>
wrote:

>I just wrote a simple driver for a 16750 UART and wondered if there are still 
>(embedded) systems that use the 5 and 6 bits character length format?

None I'm aware of.  But a single lifetime must still be considered
very limited in scope.

>A quick google search showed that 5 bits/1.5 stopbits were used for old 
>mechanical teletypes, not sure what 6 bits are used for.

There was a lot of excitement with the early teletypes.  They went
over very well for businesses large enough to afford them.  The one I
remember used either 5 or 6 bits (I was young then but can't recall
any lower case on it or much punctuation but it was small and fit in
my dad's office at home.)

Through experimentation years later I found that teletypes, such as
the KSR35 and ASR33, consistently operated (unless they were broken)
with 2 stop bits.  But enough would have trouble with certain streams
if 1.5 stop bits were used that I went back to consistently using 2.

One of the devices I modified to turn into a printer was an IBM model
85 electric typewriter.  On that one, I carefully calibrated each
printer action and inserted appropriate delays in the software, using
software buffer controls to allow the host computer to know when to
sent more text in order to make the whole thing work well.

The basic thing here is that if the serial stream is used with non-
mechanical display systems (glass screens, for example) or host
computers, you probably are just fine.  If there is some likelihood of
a mechanical device there, then 1.5 or 2 may be better.  It may also
help a little if you want to communicate with another embedded device
that uses a software uart that doesn't use finely timed sampling
divisions or where it's sampling may be inaccurate.

>I assume these formats are no longer used but I might be wrong,

Depends on the circumstances.  You need to weigh the likelihoods
against the extra effort, documentation, or after sale phone calls
asking "what does this mean?" and so on.  Complexity in your device
costs money after the sale, even if it is easy to code up, because it
has to be supported and educating customers on something this arcane
may cost way more than the feature is worth to a few.  But if you can
mitigate that part well, then why not keep the capability around?

Now, only glancing for a moment at your website, I gather this may be
about VHDL functionality.  That complicates questions about end use,
as you are supplying suppliers and pretty much cannot say what some
will care about.  But you also can supply a version that supports 1,
1.5, and 2 stop bits as well as a version that only supports 1 stop
bit and just see where your customers take you.

Jon