From owner-freebsd-hardware Mon Jul 1 03:29:28 1996 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id DAA17218 for hardware-outgoing; Mon, 1 Jul 1996 03:29:28 -0700 (PDT) Received: from Relay1.Austria.EU.net (relay1.Austria.EU.net [192.92.138.47]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id DAA17203 for ; Mon, 1 Jul 1996 03:29:18 -0700 (PDT) Received: from shraero.UUCP by Relay1.Austria.EU.net with UUCP id AA12955 (5.67b/IDA-1.5 for hardware@FreeBSD.org); Mon, 1 Jul 1996 12:29:13 +0200 Received: by shraero.co.at (5.x/SMI-SVR4) id AA14021; Mon, 1 Jul 1996 12:22:27 +0200 Date: Mon, 1 Jul 1996 12:22:27 +0200 From: kaufmann@shraero.shraero.co.at (Roland Kaufmann) Message-Id: <9607011022.AA14021@shraero.co.at> To: hardware@FreeBSD.org Subject: Re: muliport boards - building a PPP dialup server Sender: owner-hardware@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk Michael Smith wrote: >The 16650 is a 16550 with a 32-bye FIFO. Neither are suitable for >512KBps; at this speed you have a new byte arriving every 16us, or a >full FIFO after only 512usec. This is too fast for anything other >than a dedicated system. > > > - A 486 can service around 40,000 ISA interrupts per second, assuming > minimal interrupt processing time. Now 40000 interrupts/s gives 25us between interrupts, so it should be possible to handle several UARTS. -- best regards Roland Kaufmann Roland Kaufmann roland.kaufmann@shraero.co.at Senior Systems Engineer/Systems Design Phone: +43 1 80199 5563 SCHRACK Aerospace Fax: +43 1 80199 5577 Breitenfurterstr. 106-108 A-1120 Vienna, AUSTRIA