Date: Tue, 02 Jul 1996 23:57:07 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@HeadCandy.com> To: Michael Smith <msmith@atrad.adelaide.edu.au> Cc: jparnas@jparnas.cybercom.net (Jacob M. Parnas), stesin@elvisti.kiev.ua, Kevin_Swanson@blacksmith.com, hardware@freebsd.org, bsdi-users@bsdi.com Subject: Re: muliport boards - building a PPP dialup server Message-ID: <199607030657.XAA11148@MindBender.HeadCandy.com> In-Reply-To: Your message of Sun, 30 Jun 96 01:06:38 %2B0930. <199606291536.BAA21513@genesis.atrad.adelaide.edu.au>
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>> Thanks for the information. But as I said in a recent message, the new TI
>> chip can go over 900Kbaud/sec. This isn't so fast. Its 1/10th the speed
>> of old ethernet and 1/100 of new 100 Mbit/sec ethernet.
>As I've already said, the 16550 will go faster. The problem is that the
>programming model for the 16550 makes no provision for more divider steps,
>and thus any software that wants to talk to either of these chips must be
>modified to understand the higher speeds.
>
>Quatech do a card called the DS-100 with a pair of PC16550D's and an 18MHz
>clock and a jumperable /1 /2 /5 /10 divider that will allow your to
>run your 16550 ports significantly faster.
The Hayes ESP cards have a software programmable divider. Default is
1x, which in 16550-compat mode gives you a max of 115,200bps. You can
use the software config program with the card and program a 1x, 2x,
4x, or 8x multiplyer (if I remember right). Meaning that if you had
the 8x multiplyer set, you could set it so Free/NetBSD thought you
were doing 115,200bps, but the port would really be pumping
921,600bps.
I don't know for sure (don't have the programming docs nearby), but I
suspect that the multiplier can also be set via the "enhanced-mode"
programming registers.
Both NetBSD-current and FreeBSD-current have explicit support for the
ESP card (to set bigger high/low-water marks on the buffer, and send
in larger bursts).
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Michael L. VanLoon michaelv@HeadCandy.com
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
Roll your own Internet access -- Seattle People's Internet cooperative.
If you're in the Seattle area, ask me how.
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