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Date:      Sat, 24 Feb 1996 13:02:09 +1030 (CST)
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        terry@lambert.org (Terry Lambert)
Cc:        petzi@zit.th-darmstadt.de, hackers@FreeBSD.ORG
Subject:   Re: 230.400 bps on serial port
Message-ID:  <199602240232.NAA25720@genesis.atrad.adelaide.edu.au>
In-Reply-To: <199602231727.KAA23715@phaeton.artisoft.com> from "Terry Lambert" at Feb 23, 96 10:27:49 am

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Terry Lambert stands accused of saying:
> 
> > I need a reliable data transfer rate of 230.400 bps on the serial port for
> > PPP. Can that be done ? getty only has a setting for 115.200 bps. I have a
> > Gigabyte 586 ATEP mainboard with FIFOs. Can I use them for 230.400 bps, and
> > how ? Or should I buy a special serial card for that ?
> 
> That is MIDI speed.  I wonder what you are doing?  8-).

MIDI is 32K.  (Yes, I owned several ATARIs and hiked the MIDI UART up to
500K for networking, but it's a 6850 and not at all up to it.)

> The Intel UART parts, as much as Dennis loves them, use a clock divider
> and the standard frequency for the crystal makes it impossible to get
> that data rate out of the serial hardware (I assume you have an Amiga
> or similar current loop converter for RS232?).

You get 230,400 by doubling your crystal (~3.6) and dividing for 115,200.
Quatech do a dual port card (the DS-100) with an 18MHz (10x) crystal and
a jumper-selectable divider (/1, /2, /5 or /10).

You would want to remove the (soldered in) 16550's and use 16650's (32-byte
FIFOs) and update the sio driver to support them.

> My personal opinion is that the Intel parts are utter crap.

Hear Hear!

> Or you could get a sound card that the sound driver supports MIDI for;
> see the sound driver comments/documentation for details.

All of the cheap MIDI interfaces are 6850 emulations.  Wonder why?

> 					Terry Lambert

Sounds like a late night there 8)

-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
]] Genesis Software                     genesis@atrad.adelaide.edu.au   [[
]] High-speed data acquisition and      (GSM mobile) 0411-222-496       [[
]] realtime instrument control          (ph/fax)  +61-8-267-3039        [[
]] Collector of old Unix hardware.      "Where are your PEZ?" The Tick  [[



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