Can Python serial support run at 45.45 baud?

[Grant Edwards]

On 2009-02-14, John Nagle <nagle at animats.com> wrote:
> John Nagle wrote:
>
>>    OK, tried to open the port, using Python 2.6, latest PySerial
>> and PyWin32:
>> 
>>     ser = serial.Serial(port, baudrate=baud,
>>             bytesize=serial.FIVEBITS,
>>             parity=serial.PARITY_NONE,
>>             stopbits=serial.STOPBITS_TWO)
>> 
>> ValueError: Cannot configure port, some setting was wrong. Original 
>> message: (87, 'SetCommState', 'The parameter is incorrect.')
>> 
>>    Something doesn't like "serial.FIVEBITS".  That's a valid value, 
>> according
>> to "http://pyserial.wiki.sourceforge.net/pySerial".  If changed to 
>> "serial.EIGHTBITS",  the code will execute, but of course does the wrong
>> thing.   That looks like a bug.
>
>     OK, here's what's wrong.  The allowed numbers for stop bits in Windows are
>
> 	ONESTOPBIT	0	1 stop bit.
> 	ONE5STOPBITS	1	1.5 stop bits.
> 	TWOSTOPBITS	2	2 stop bits.
>
> The Python interface, however, only exports STOPBITS_ONE and STOPBITS_TWO.
> See "serialutil.py", at line 9, and "serialwin32.py" at lines 141-146.

That should be simple enough to fix.

> Linux has a different set of restrictions; Linux offers only 1 or 2 stop
> bits, and won't do arbitrary baud rates via the "termios" data structure,
> although there are other ways to request that.

It can be done via the ioctl that setserial uses, but that's
specific to a very few low-level drivers like the 16x50 one --
which is probably the one that matters to the OP, though he
hasn't said so.

-- 
Grant