🚀 go-pugleaf

In article <2030@netmbx.UUCP> hase@netmbx.UUCP (Hartmut Semken) writes:
>szhu@tasha.poly.edu (A1 shu bin zhu (cs) ) writes:

>>Is there a way to set the serial port above 19200 baud on the ST?
>>The MFP chip can handle upto 56.2K baud, there must be a way.

The Motorola Spec says 64kbps max asynch, 1Mbps synch.

>There is no way to do it in software:

I hate to disagree with you, but you're wrong about this...

>One of the timers in the MFP is used to generate the send and receive
>clock for the serial interface. Using the standard clock frequency and a
>pre-divider by four (this is necessary for async. operation) it can
>generate clocks up to 19200 Baud.

Actually the predivide is by 1 or by 16, with div 16 for async and div 1 for
synchronous modes. However, even tho div 1 is meant for synchronous comm.,
the MFP will operate asynchronously with this setting. Unfortunately, the
crystal frequency is so bizarre that 38400 is the highest "standard" bit
rate you can coax out of it. (2.4576MHz.) You can set the counter for 76800,
but I've not tried it, I'm sure it would fail miserably. I got a lot of noise
running at 38400 between my ST and a NeXT box. Of course, I haven't tried
between two STs yet. 

Someone else commented to me (sorry don't remember, this was a while back)
that there's no way you can get a consistently good signal using this trick,
because the MFP is struggling so hard to detect the pulses at these speeds.
So, if you're really serious about it, you're probably better off doing the
hardware mod.

--
  -- Howard Chu @ University of Michigan

Flame all you want - we'll take more.