Fusion Forty (68040) and A2091 Troubles

[fortytwo]

Hi,

i'm having trouble getting my Fusion Forty Accelerator Board and my A2091 SCSI Controller to work together. As soon as the Fusion Forty Board is installed in the System, i randomly get checksum erros or the system just freezes while accessing the hard drive (partitioning, formating, copying files).

The errors only accur while accessing the harddisk or CDROM. There is only one harddisk attached to the A2091. Running some Demos or Games from disk works very well.
The A2091 also performs very well using only the 68000 chip, without the Fusion Forty installed.
I also tried a 2620 accelerator. It worked without problems (for about two days). Than, while copying about 90 MB from a Tandem IDE Controller, i got an Guru, und the filesystem was damaged. I did however try to tweak the Maxtransfer settings before.)

First i tried various hard drives of different sizes. With no success.
Then i upgraded the Fusion Forty Roms to the most recent version (3.4). No help either.

Then i realized the errors occur wether or not the Fusion Forty was switched on or off (there is a disable switch attached to the back of the card).

I recently upgraded the A2091 Roms to Rev. 7.0, but the situation didn't improve.

I also tried various mask/maxtransfer values, since the A2091 cannot access the memory on the Fusion Forty. This didn't help either. I didn't expect so since afaik the A2091 uses PIO access if DMA is not possible, and there are 2 MB of Fast Memory installed on the A2091. I alsa disabled the additional 2 MB for testing purposes.

Disabling FastKick didn't help either, as did the various setff settings.

The PSU works fine, i measured every wire.

I did, however, manage to get a BSC Tandem IDE Controller to work. The Controller uses PIO access only. No hickups so far.

It's a revision 6.2 board. The only extension added is a Multivision 2000 Scandoubler. I also removed it for testing purposes, but as aspected, this didn't pave the way to a stable system. The accumulator was removed after it did as far as i can tell little damage to the board (the keyboard connector shows some loose connection, so i will have to install a new connector). The board was cleaned and i also checked every checked every chip for oxidation.

Do you think the Fusion Forty Board is broken? Or the A2091? I'm running out of ideas and nerves to stress.

[Unknown_K]

Sounds like a conflict to me if they both work fine on their own. Running a 2091 without onboard ram makes it extremely slow because of PIO mode.

[Secret Vampire]

From looking at the Fusion 40 faq http://www.lundblad.net/mattias/F40-FAQ.txt it seems that with no ZII RAM, the A2091 doesn't do PIO to fast, but uses DMA to chip, which is then copied to fast, which is slower than either PIO or having a suitable piece of fast RAM to DMA to.

Anyway, potential sources of problems could be not using the version of the 68040.library that came with the F40, or possibly using old versions of the A2091 ROM. I know from experience that the F40 is somewhat picky about which ZII cards it would work with, my Trumpcard grand slam was an absolute no-no, but I think I did have the A2091 working with it for a while, until I upgraded to a GVP series II. However, the card was never entirely stable, I put it down to the poor condition mine was in when I got it (non working and covered in some kind of oil, which had reacted with the IC sockets and turned the metal parts green), however, it was the first 68040 accelerator on the market, and as such probably lacks the refinements of later alternatives. The rev 2.0 ones are probably better, and certainly faster with their 35MHz cpu and interleaved RAM for better memory performance.

[fortytwo]

@Secret Vampire: Both the Fusion Forty and the A2091 are equipped with the most recent roms (3.4 and 7.0), and yes i have installed the 68040.library from RCS.