Date: Thu, 9 Feb 1995 08:01:23 -0600 (CST) From: obiwan!bob@uudell.us.dell.com (Bob Willcox) To: joerg_wunsch@uriah.sax.de Cc: Pat_Barron@transarc.com, hackers@FreeBSD.org Subject: Re: FreeBSD with Bustec BT-542B SCSI interface Message-ID: <m0rcZQx-00030ZC@obiwan.uucp> In-Reply-To: <199502061749.SAA17102@bonnie.tcd-dresden.de> from "J Wunsch" at Feb 6, 95 06:49:13 pm
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J Wunsch wrote:
> All my problems went away with the following steps:
>
> . use the bt driver,
> . disable ISA DMA emulation from the EISA setup,
> . configure the board to use level-triggered interrupts, and
Hmm, I didn't realize the bt742a.c device driver would work with
level triggered interrupts. Does that mean that I can put multiple
BT747S's on the same IRQ?
> . configure my board to use an ISA clock close to the standard 8 MHz
> (it's been 6 MHz before due to a bad floppy controller, but the
> Bt 742 refused to work at this clock)
This reminds me of the strangeness of one of my systems here with a BT747S
(actually, 3 of them and they *all* behave the same way on this). When I
updated the system from a 486DX2/66 to a 486DX2/80 I (obviously) had to
increase the MB oscillator to 40MHz (from 33MHz). In doing this I set my
bus speed to CPUCLK/5 (i.e., 8MHz). At that speed, I could boot off of the
hard disk but *not* the floppy! (At the old 33MHz speed I had the bus speed
set to CPUCLK/4 [8.3333MHz] and that worked.) So, I tried the 7.159MHz bus
speed. With that, I could boot from the floppy again but now the hard disk
failed to boot!! I finally settled on CPUCLK/4 (again, only now the bus
speed is 10MHz) and both floppy and hard disk boot...go figure?????
Has anybody else seen this kind of wierd behavior with the Buslogic BT-747S
cards? As I said above, I have 3 of these cards in the system did try the
others (for floppy connection). They all failed to boot the floppy at
a bus speed of 8MHz.
--
Bob Willcox ...!{rutgers|ames}!cs.utexas.edu!uudell!obiwan!bob
Austin, TX or try: @uudell.us.dell.com:obiwan!bob
512-258-4224 (home), 512-838-3914 (work)
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