Q: Adaptec 1740 Enchanced mode + Hint chipset
Marko Korhonen
----
We have some problems with eisa Hint (caesar) chip-set.
The biggest problem is trying to use adaptec 1740 (bios 1.40)
on enchanced mode. In standard mode it works fine.
So we need little help ...
Email : mkor...@vipunen.hut.fi
robert.k.nichols
>We have some problems with eisa Hint (caesar) chip-set.
>The biggest problem is trying to use adaptec 1740 (bios 1.40)
>on enchanced mode. In standard mode it works fine.
>
>So we need little help ...
You need more than a little help. You need a new motherboard. That HiNT
Caesar "Mini-EISA" chipset doesn't support 32-bit addressing on the I/O
bus. It has the same 24-bit 16-Megabyte addressing limit as the standard
ISA bus. So, your bus-mastering SCSI adapter will fail miserably in
enhanced mode because the 8 high-order address bits are being ignored.
(With appropriate additional buffer/driver chips on the motherboard, the
HiNT Caesar chipset _can_ support 32-bit addressing from DMA bus masters,
but the DMA controller built into the chipset still only supports 24
address bits, so non-bus-mastering DMA devices, such as sound cards,
would still be unable to access memory above 16 Megs.)
--
Bob Nichols
AT&T Bell Laboratories
rnic...@ihlpm.ih.att.com
Ralph Valentino
>In article <1993Oct30.1...@ousrvr.oulu.fi> mkor...@vipunen.hut.fi (Marko Korhonen) writes:
>>We have some problems with eisa Hint (caesar) chip-set.
>>The biggest problem is trying to use adaptec 1740 (bios 1.40)
>>on enchanced mode. In standard mode it works fine.
>>So we need little help ...
>
>You need more than a little help. You need a new motherboard.
Actually, it isn't quite that bad. The Adaptec 1740 will still "work"
if you disable the appropriate features. Edit the .CFG file and
change:
SHARE = "AHA1740" to: SHARE = NO
TRIGGER = LEVEL to: TRIGGER = EDGE
And then delete/add the board using the EISA Config Utility (ECU)
using the new .CFG file. It should work fine after that.
>That HiNT Caesar "Mini-EISA" chipset doesn't support 32-bit addressing
>on the I/O bus. It has the same 24-bit 16-Megabyte addressing limit
>as the standard ISA bus.
This is true in the "Super-ISA" configuration. In the "P-EISA"
configuration, busmastering devices can access all 32 address bits.
However, his problem is most likely the lack of level sensitive
(sharable) interrupts.
>So, your bus-mastering SCSI adapter will fail miserably in enhanced
>mode because the 8 high-order address bits are being ignored.
If he has the Super-ISA configuration and more than 16Meg of main
memory, yes. If he has the P-EISA or less than 16Meg of main memory,
this isn't a problem.
>(With appropriate additional buffer/driver chips on the motherboard, the
>HiNT Caesar chipset _can_ support 32-bit addressing from DMA bus masters,
>but the DMA controller built into the chipset still only supports 24
>address bits, so non-bus-mastering DMA devices, such as sound cards,
>would still be unable to access memory above 16 Megs.)
True, anything using the motherboard's DMA (including the floppy
drive!) will have this 16Meg problem on the HiNT based motherboards.
This can be worked around in software by using double buffering - if
the OS drivers are smart enough to detect it, but that's a big if.
-Ralph
===============
Ralph Valentino (ra...@chpc.org) (ra...@wpi.wpi.edu)
Hardware Engineer, Worcester Polytechnic Institute
Center for High Performance Computing, Marlborough MA