From owner-freebsd-hackers Fri Jun 9 01:19:13 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id BAA22679 for hackers-outgoing; Fri, 9 Jun 1995 01:19:13 -0700 Received: from gndrsh.aac.dev.com (gndrsh.aac.dev.com [198.145.92.241]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id BAA22667 for ; Fri, 9 Jun 1995 01:19:07 -0700 Received: (from rgrimes@localhost) by gndrsh.aac.dev.com (8.6.11/8.6.9) id BAA05571; Fri, 9 Jun 1995 01:18:45 -0700 From: "Rodney W. Grimes" Message-Id: <199506090818.BAA05571@gndrsh.aac.dev.com> Subject: Re: aha1542 bus speeds To: kuku@gilberto.physik.rwth-aachen.de (Christoph P. Kukulies) Date: Fri, 9 Jun 1995 01:18:45 -0700 (PDT) Cc: freebsd-hackers@freefall.cdrom.com In-Reply-To: <199506081858.UAA06489@gilberto.physik.rwth-aachen.de> from "Christoph P. Kukulies" at Jun 8, 95 08:58:37 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 699 Sender: hackers-owner@FreeBSD.org Precedence: bulk > > The AH1542CF allows a couple of bus speeds in the BIOS setup (^A) amongst > others there are 10MB/s, 8MB/s. When looking at /sys/i386/isa/ah1542.c > there is the array aha_bus_speeds[]= {0x88,100},{0x99,150} and so on. > Why are these ns figures not reflect the actual (possible) MB/s values? They do if you look at a 1542B. These numbers come right out of the 1542B programmers manual, and a 1542B has a jumper that allows the settings 5.0, 5.7, 6.7, 8.0 and 10.0MB/sec. This values correspond to 200.0, 175, 150, 125, and 100ns. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Custom computers for FreeBSD