Upgrade firmware ACARD SCSI to IDE bridge 3.77 to 1.77b

[ataradov]

Before we had Python, we had the Unix shell.

Yes, and then we came up with a way to make things maintainable instead of cryptic one-liners that only work on one OS.

I'm sure it is possible to pack this all into one line of Python code, but this is not an obfuscated coding contest.

Edit: of course, it is possible. Here is a Python one-liner that is shorter than the shell one (and arguable more readable):

Code: [Select]

open('out.bin', 'wb').write(bytes([j for i in open('in.bin', 'rb').read() for j in [i, 0xff]]))

It is still shorter even if you run it as a standalone command in a shell-style with python -c "...."

[DogP]

Hi Everbody, I am looking to use the acard 7722 for a Akai Sampler which is based on a 386embedded, target is to attach sd card writer IDE. I have in a second Akai sampler with a working Acard. Is it possible to extract the firmware out of the other model and put it into a 7722 card? If yes, what do I need. There is no need to use SCSI2SD or ZULU SCSI, because the Akai is using Fat32 format and one SSD or sd card is enough. I look for a cheaper solution. And the acard is a lot faster compared to the SCSI2SD, I have both in the same machine. Any help would be fine, there are quite a lot AKAI User who look for an alternative. SCSI2SD is not working anymore because of shortage of parts. Thanks for reading

If your working ACARD is compatible with the 7722, you can desolder the flash chip and dump it.  But there are a lot of versions of the firmware already available to download, so I wouldn't expect that you'd need to dump your old one.

You should just need to desolder the 7722's flash chip, (optionally) install a socket, burn the appropriate firmware to the flash chip, and reinstall on the 7722.  IIRC, I tested and had good luck with both 1.69H and 1.73Q.

DogP

[fisafisa]

Hi.
Where can I find the  7726 BIOS versions 1.69H and 1.73Q?

I am planning to convert a couple of 7722 to 7726


Many thanks!

PS I found them.
If anybody needs them please pm me.

[fisafisa]

summary of what  l learned.

1) firmware 1.73q works
16 bit scsi
also 8 bit using a working adapter!
works with sd to ide adapter

2) you have to de-solder the flash and reflash it
I notice that the flash had the 16K code repeated twice
so I did the same: one copy at 0000 and one at 0x4000

3) I used sockets in 2 cases and in one I soldered directly
!check all connections. I never got it 100% first time

4) test components separately.
I checked the sd to ide and found problems in a sd
I checked with a 16bit connection first
Last I introduced the 8 to 16 bit adapter
I found problems at each step

5) the scsi 8 to 16 adapters on ebay are a disaster:
- they connect to ground D8 D15 when they should have been left floating
there are two pads where to place a 4.7K resistor to Vterm
to remove the short I had to remove copper near one of the pins on the edge of the connector.
The short is just on one side of the pad under the 68 pin connector
a second short to ground is on the opposite edge but on the visible side
the short is an intentional connection: 4 thermal relief connections to the ground plane

a second connector also had a further short, not a systematic flaw in the pcb, but I think a problem with the soldering of the connector
the connector male 68 pin is in fact an idc connector soldered directly to the pcb
the knives have been somehow squeezed close and inserted inside the pads and it happens that before inserting they can damage the pcb and connect to a nearby trace...

the 68 to 50 pin conversion has proven to be the most difficult part.

F

[DogP]

the scsi 8 to 16 adapters on ebay are a disaster

That's what I noticed as well.  Did you end up modifying the ebay adapter to fix all the problems, or build a new one?

DogP

[fisafisa]

out of 3 now 2 are working!

First I took apart one to see the layout in detail
This way I understood the various problems of the device.
1) the 9 higher bits are connected together and to a pad to host the 4.7K resistor to Vterm.
unfortunately on one corner they are shorted to ground
2) the connect idc knives sometimes are bent and cut into traces creating shorts

one was an easy fix: add resistor and remove short to ground
the second had 2 shorts due to bent knives. I had to drill through to cut the traces on top of the 68 pin connector and to cut the trace near the 50 pin one
Then I routed two wires to reestablish the connection
 A third wire is because I had to cut a trace to allow a wire to go across in between the two connectors.

See the images below

[feipoa]

BTW, I uploaded the SCSI adapters to Github:
https://github.com/pdaderko/16702B/tree/main/SCSI_50_to_68_male
and
https://github.com/pdaderko/16702B/tree/main/SCSI_50_to_68_female

I'd definitely be interested to hear results if you give either of these a try...

DogP

Thank you! I just ordered these two PCB's from JLCPCB.  Do these PCB's act as terminator cards, meaning, the AEC-7722 should be the last item on the cable and I would not use a 50-pin cable with termination?

[DogP]

Do these PCB's act as terminator cards, meaning, the AEC-7722 should be the last item on the cable and I would not use a 50-pin cable with termination?

No, these only adapt the 16-bit device to operate on the 8-bit bus.  This adapter terminates the (unused) upper byte for the device, but the lower byte (i.e. your system's 8-bit SCSI bus) still needs to be properly terminated.

DogP

[feipoa]

I'll begin testing these soon.  However, I wanted to caution others not to straight away start disassembling their 68-pin SCSI cables. I took apart two cables so far and both of the crimped ends have different spacing compared to what DogP has laid out on the PCB.

I may need to use the PCB variant that solders directly to the ACARD adaptor.  Once the PCB is soldered on, am I still able to use the 68-pin connector for CD-ROMs without resoldering DogP's PCB? In viewing the traces, it seems like this should be OK.

[feipoa]

DogP, I've soldered on one of the boards and have a few questions:

a) do you know if your upper-byte-terminated-adaptor needs to be on the end of the SCSI cable, e.g. just before the terminator block, or can it be somewhere in the middle of the SCSI cable, with say, other devices downstream of it?

b) I was planning on setting up a system which has ACARD on CD-ROM, ACARD on CF, and a SCSI ZIP drive. Do you think the ACARD-CDROM unit needs one of your adaptors as well, or will a simple 68pin-to-50pin plug suffice?  See attached photo.

[DogP]

I took apart two cables so far and both of the crimped ends have different spacing compared to what DogP has laid out on the PCB.

Can you post a picture of what the IDC connector looks like?  I've seen two different spacings, but had no problem getting both of them into the adapter (one had all 4 rows equally spaced, the other had the top two and bottom two rows slightly closer to each other).  Curious what others are out there.

Once the PCB is soldered on, am I still able to use the 68-pin connector for CD-ROMs without resoldering DogP's PCB? In viewing the traces, it seems like this should be OK.

With the 50-pin adapter installed, you won't be able to use the 68-pin connector, since it terminates the upper byte.  Well, to clarify - you won't be able to use the 68-pin cable in 16-bit mode at least, since the upper byte is shorted together and pulled to TERMPWR.

a) do you know if your upper-byte-terminated-adaptor needs to be on the end of the SCSI cable, e.g. just before the terminator block, or can it be somewhere in the middle of the SCSI cable, with say, other devices downstream of it?

It shouldn't matter where it is, since it's only intending to terminate the upper byte of the device (16-bit capable device running in 8-bit mode), not the entire cable.  Not sure if it's clear, but a 50-pin SCSI ribbon has 8 data bits, and a 68-pin ribbon has 16 data bits.  So, if you're connecting everything with a 50-pin ribbon cable, you're only using an 8-bit interface, and the upper byte which may be terminated at one device is completely unconnected at another device because those lines aren't connected through the 50-pin cable.

b) I was planning on setting up a system which has ACARD on CD-ROM, ACARD on CF, and a SCSI ZIP drive. Do you think the ACARD-CDROM unit needs one of your adaptors as well, or will a simple 68pin-to-50pin plug suffice?  See attached photo.

I'm not familiar with that other adapter you have... if it's wired correctly, it should function identically to my adapter.  The problem I ran into was the couple of 50 to 68 pin adapters I tried incorrectly terminated the upper byte (e.g. connected to GND), which caused the device to not work.  If the adapter you have works with the CD-ROM alone, I'd expect it to work fine with the whole system.

DogP

[feipoa]

Thanks for your answers.  So the 68-pin connector will still work with your adaptor installed, but the CD-ROM or HDD will only be able send a datastream of 8-bits wide.

That 50-to-68 pin SCSI adaptor you see on the CD-ROM drive - as I recall it, it let the CD-ROM work just fine on a 50-pin cable, but not a HDD/CF card.

Attached are the two 68-pin SCSI cable ends I pulled off.  One has the spacing too close together, and the other too far apart. I could not get leads into your PCB.

[feipoa]

I pulled apart a 3rd SCSI cable and it has different pin spacing than the first two cables and also does not fit the PCB.  They really didn't standardise these crimp ends.

[DogP]

Interesting... thanks for the report.  I just found the cable I used, and the part numbers listed are:

Inventec 6017A0000101
Compaq J2035
296016-008

You can see from the holes left in the cable that the spacing was narrower between the two middle rows, but I was still able to push it into the holes on the PCB... just took a little bit more effort than the evenly spaced one.

This is the exact cable I purchased: https://www.ebay.com/itm/143939246933 ... looks like they've still got one available.  I don't remember where the other connector I tested came from - I think just from a misc. cable I found laying around, which had the same total spacing from rows 1-4, but all 4 rows were evenly spaced.

DogP

[feipoa]

I tried forcing all 3 connectors earlier, but could not get them into the PCB.

I considered buying your cable, but then noticed a comment in that eBay listing stating that buyers may not get what is pictured, but rather get something of identical specs/function.

[feipoa]

I left an open question a few days ago concerning my 50-pin female to 68-pin male SCSI adaptor.  Unfortunately, this adaptor alone was not sufficient to allow my IDE CD-ROM drive to work with an ACARD AEC-7722 and my ISA SCSI host controller. I had to use DogP's solder-on PCB on another ACARD unit.  The good news is that the IDE CD-ROM and CF card are now both functional with the SCSI 8-bit, 50-pin narrow controller using DogP's adaptor.  I tested it briefly in DOS with an Adaptec AHA-1522B and an AHA-1542CP. I will be building a system around this configuration, so more testing is to come.