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Offline stephanTopic starter

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A2091 and 68040
« on: March 19, 2007, 02:57:41 PM »
Hi,

does anyone have any experience with an A2091 SCSI Controller and a 68040 card? I'm using a Fusion Forty Accelerator in an A2000 Rev 6.2. The F40 Roms are the most recent ones (3.4), the A2091 uses Rom Rev. 6.6 (which is reported to work in the Fusion Forty FAQ, although various Hardware sites report one would need Rev. 7.0 Roms with the 68040). The A2091 is equipped with 2 MB Ram. I get quite a lot Read/Write errors as long as the Fusion Forty is activated. I can only format the disk (not quick format) when the F40's Fastkick Option is disabled. But beyond that i get read/write errors. If i enable Fastkick, formatting gets stuck at about 0 %. I use Mask 0xFFFFFF atm, but i tried various other values. As soon as i disable the accelerator board the A2091 works flawlessly.

A Tandem IDE Controller works flawlessly after some tweaking with the Mask/MaxTransfer values. The A2091 works fine with a 2620 accelerator board.
 

Offline Ral-Clan

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Re: A2091 and 68040
« Reply #1 on: March 19, 2007, 03:15:21 PM »
I have a ton of experience with my A2091 and my PP&I 2000/040 board.  040 boards and the A2091 have notorious problems, until you get all the chips updated.  Once you get all the chips updated and the patches installed, things will run smoothly.

I had the same problems.  I think I had to upgrade to the 7.0 ROMs and also upgrade the Western Digital chip on the board to the -08 version (the latter chip wasn't that expensive, as I recall).

Later on, I bought the GURU-ROM for this board, which also works well (this is not necessary if you have the 7.0 ROMs, but it doesn't hurt).

Make sure you have the proper version of the WD chip though - that would be the first thing I would try.  Also make sure there is some RAM installed on the A2091.

Also, check the board....are the terminating resisitors by the internal SCSI slot present or removed?  If removed, then you will have to terminate the external connector with a DB29 type external terminator.

You will also notice that things are transferring very slowly on the SCSI bus.  There is a DMA problem when using an 040 and the A2091 in conjuction.  I used the patch available on Aminet called vbak2091 (or something similar) to increase the SCSI speed back to normal levels.  This seems to be the best of all the patches I tried.
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Offline stephanTopic starter

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Re: A2091 and 68040
« Reply #2 on: March 19, 2007, 03:26:52 PM »
Which resistors are the termination resistors? But i think this is not the problem since the card works fine using a 2620 accelerator. I will try to get my hands on some new roms and the chip, but i think it will be cheaper to buy another controller.
 

Offline Ral-Clan

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Re: A2091 and 68040
« Reply #3 on: March 19, 2007, 04:00:23 PM »
The on-board terminators are three black, blue or red resistor packs near the internal SCSI slot at RN1, RN2 and RN3 as seen in this photo:

http://www.amiga-hardware.com/download_photos/a2091_2_big.jpg

If they are missing you will need to terminate your external SCSI port.

As for replacing chips....since you already have the 6.6 ROMs installed, for now just try to upgrade the Western Digital chip at U4 on the other side of the SCSI connector.  These chips are really cheap to get.  If you already have chip 00-04, you will need the 00-08 version.  They were also used in Macs and PCs so they are available on eBay for dirt cheap.  I got mine from Software Hut about 6 years ago....I think it cost me $12.99.

Once you get the A2091 working, it's pretty reliable.

Note: if you only have one internal hard drive, the 6.6 ROMs might be just fine (once you upgrade the WD chip).  If you plan to get into attaching scanners, multiple drives, and maybe a CD-burner you may find you need to upgrade the ROM to 7.0 or a GURU-ROM.
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Offline stephanTopic starter

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Re: A2091 and 68040
« Reply #4 on: March 20, 2007, 07:17:38 AM »
I recently got some news: A user has exactly the same problems  with the same Accelerator using a Oktagon 2008 Controller.