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To: Terry Lambert <terry@lambert.org>
cc: hackers@freebsd.org, bde@freebsd.org, rgrimes@freebsd.org
Subject: Re: serial ports at 230k 
In-reply-to: Your message of "Thu, 06 Feb 1997 14:31:48 MST."
             <199702062131.OAA17929@phaeton.artisoft.com> 
Date: Thu, 06 Feb 1997 13:42:12 -0800
From: Paul Traina <pst@jnx.com>
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That's what I thought too,  but everything I read suggests that no special
hardware is actually necessary.  I know the clock divisor goes to 0 at 115k,
so I'm assuming that there's a clock multiplier somewhere else that can
be kicked with relatively modern 550s.

W95, with appropriate prodding, was happy to set my serial port speed to
what it claimed was 230k.

  From: Terry Lambert <terry@lambert.org>
  Subject: Re: serial ports at 230k
  > Does anyone have any experience with running 16550A's at 230kbps
  > under FreeBSD?
  >
  > Yes, I know, the driver doesn't support it currently, but has anyone
  > played?
  
  The hardware doesn't support it, unless you changeout your clock
  crystal (assuming it isn't using an on-board clock generator in
  an ASIC containing it and the UART both).
  
  All the driver does is translate manifest conatants to bit patterns,
  so it doesn't care if B300 (for instance) really makes the UART go
  into 300 baud mode or not.
  
  8-).
  
  
  					Terry Lambert
  					terry@lambert.org
  ---
  Any opinions in this posting are my own and not those of my present
  or previous employers.