Slow serial baud rates

[SignalX]

Hi all,
I am really new to these wonderful devices and have been having a great time learning from making the little project boards do things from simple programs in basic.
These days, it seems everyone wants to go faster and faster but is there a way to configure a PICAXE to work at low baud rates.
According to the good book, when programming in basic, the internal serial port can be made to work at 300 baud.
My question is can it be made to run at 110 baud or even 50 baud and if 50 baud is possible, can it have 5 data bits instead of 8?

Cheers,

Moved from Finished Projects. e

 

[eclectic]

Can you supply a little more detail please?

What's it for? :- Rig / RTTY ...........

e

edit.

See below for Ian's
50 Baud crystal ball.

 

[Paix]

To convert from ASCII to 8 bit to ITA2 5 unit code, then you would merely select the appropriate codes from the ASCII character set that gave the appropriate ITA2 character, with the last three data bits being at a holding mark polarity and so looking like a rather extended stop bit.

Selecting 8 bits no parity and one stop bit would allow you to use 5 data bits and four stop bits. So best be using 50 baud rather than 45.45 if you are in a hurry . . .

You would need to use a look up table if you wanted to translate between the two. Receiving it and generating it is quite different from displaying it of course.

On the receive side you would be a bit pushed as you are reliant upon the transmitter giving you a sufficient delay between characters as you have at least three bits after reception of of a 5 unit character before the receiver can be ready for the next character.

For a 5 unit telegraph beacon signal it's OK.

 

[srnet]

Whether it can be done with standard PICAXE serial in\out commands, I dont know, but Manual2 page 95 has details of custom baud rates.

What I know is very definitely possible is to 'bit bang' the serial at these very low baud rates, I have code which does a 'bit bang' of FSK RTTY at 100baud or 200baud, a PICAXE is more than capable of doing this.

You need a scope to check the timing, and to adjust the bit periods with a series of pause delays. Over a byte, start bits, data bits and stop bits, once setup its within a fraction of a percent accurate, well with the limits of what serial can cope with.

So definitely possible but why are you interested in Baudot ?

 

[nick12ab]

You can use hardware serial for custom and slow baud rates.

 

[SignalX]

Thanks for all the help guys.
The idea of the prohject that I started all those years ago, was to generate a small number of messages to feed in a sequence to a teleprinter on display in a museum.
The machines are much more impressive when doing something rather than nothing at all.
I have been using a laptop to do it but it ties up a laptop - although these days you can get an old laptop with with a real serial port for a few pounds.
Regards,