Reverse engineering of some ICD Link adapter

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Reverse engineering of some ICD Link adapter

Postby SofiST » Mon Aug 16, 2010 3:28 pm

Preferrably ICD Link II . I tried to mail Tecnical Support of, according to WEBsite, but e-mail address is dead. ( support@icd.com ).
Not that we have chances to get some useful info from manufacturers, even if they sale it not more.

It was proposed here couple times, among others by Ijor - to make a rev. enineering . I think that it is real, not easy, but also not extremely hard. Problem is, as may know that GAL chips are protected from reading out internal logic. But it can be get by examining behaviour. Knowing where pins are connected we can deduct their functions, and then may get slowly internal logic, by well concepted tests- Myself did couple times such examinations, although with simpler circuits, containing GALs or PALs.

The biggest problem is, I think to get one of those rare beasts. Has someone 1 piece (it should be enough :-) ) to sell. loan, give away :mrgreen: ?

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Re: Reverse engineering of some ICD Link adapter

Postby alexh » Mon Aug 16, 2010 9:24 pm

Erm, why not just use Ultrasatan? It is fully open-source, from the code for the IC down to the schematics for the PCB. It can offer you almost everything you could want from a storage device.

What feature of the ICD link II do you want?

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Re: Reverse engineering of some ICD Link adapter

Postby AtariMega125 » Tue Aug 17, 2010 2:29 am

I would study this first, the ASCS/DMA guide which includes a the schematic of a ASCI to SCSI generic host adaptor. This is the basic concept of the ASCI/SCSI host adaptor and IDE, Supra and others built on it. I use an ASCSI Plus which probably does everthing the Link 2 does but in a larger form factor with more power consumption but it also gives you a circuitboard more open to probing if you have a good logic probe. It will be a little easier than a Link 2 to check out and maybe a little less expensive.

http://dev-docs.atariforge.org/files/ACSI_DMA_Guide_6-28-1991.pdf

Ultrasatan would be the way to go if you just wanted a good storage solution. The SCSI drives that work with anything less than the ADSCSI Plus or Link 2 are getting rarer all the time while SD is everywhere and cheap. If you like to do reverse engineering just for the fun of it, reversing the ICD host adaptors would be a nice challange.
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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Tue Aug 17, 2010 7:19 am

Thanx guys. I'm aware of all mentioned, and have all linked documents.
There is still demand for ACSI/SCSI adapters, even when UltraSatan is here. Some people still has SCSI disks, and as we know ICD adapters are rare and overpriced now.
SCSI with good adapter is still faster, and SD cards over 8GB are not cheap. Don't know is US supports over 8GB ?
I don't agree that SCSI drives in range 1GB-30GB are rare now. In second hand shops I still can find them at good price. Plus, nothing lasts forever, so it's good to have chance for repairing devices or replacing wwith equivalent.

Anyway, maybe the way is to do complete new, PCLD design.

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Re: Reverse engineering of some ICD Link adapter

Postby Jookie » Tue Aug 17, 2010 8:19 am

SofiST wrote:SCSI with good adapter is still faster, and SD cards over 8GB are not cheap. Don't know is US supports over 8GB ?


8 GB -> 15 Euro, 16 GB -> 27 Euro... UltraSatan doesn't have any limit (the only one is the SDHC maximum capacity), and if there is some, then it's a bug which can be fixed with uploading a new firmware. The biggest card I have tried was 8 GB. The maximum partition size under TOS 2.0x is 512 MB, you can have max. 14 partitions (C-P), so you can use only 7 GB of space. With TOS 1.0x the max. partition size if 256 MB which results in 3.5 GB of usable space. Then I still would wonder what stuff would put people there ;)

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Tue Aug 17, 2010 10:21 am

I don't want here to discuss is UltraSatan with SD card better than SCSI disk solution.... I was always for modern, economic solutions. So, please stay at topic, if possible.
Point is not in what to do with large drives (and there are ways to use capacity over 7GB). The point is what to do when you have such drive and Atari, but no adapter, or it is broken ?

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Re: Reverse engineering of some ICD Link adapter

Postby 1024MAK » Tue Aug 17, 2010 11:41 am

AtariMega125 wrote:I would study this first, the ASCS/DMA guide which includes a the schematic of a ASCI to SCSI generic host adaptor. This is the basic concept of the ASCI/SCSI host adaptor and IDE, Supra and others built on it.
http://dev-docs.atariforge.org/files/ACSI_DMA_Guide_6-28-1991.pdf

Shame the diagram in this document is so poor (like a lot of the diagrams in Atari documents).
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Re: Reverse engineering of some ICD Link adapter

Postby AtariMega125 » Tue Aug 17, 2010 12:17 pm

SofiST wrote:I don't agree that SCSI drives in range 1GB-30GB are rare now. In second hand shops I still can find them at good price. Plus, nothing lasts forever, so it's good to have chance for repairing devices or replacing wwith equivalent.


I was thinking of smaller drives. 30mb - 1gb. I have 2 quantum lightning 730mb drives, one in my Mega 4 with a Micro SCSI host adaptor and one in my Mega STE with the original Mega STE host adaptor. This is the biggest and fastest SCSI drive that I've found that works with these adaptors. My ADSCSI plus is hooked up to a SCSI zip drive and works with just about anything but the older adaptors only work with a limited number of drives. I have an older sampler that is even fussier about SCSI and I can only go up to around 320mb. These drives are usually outrageously overpriced on ebay. I get them from old Macs that I pull out of our local recyling center.
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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Tue Aug 17, 2010 3:03 pm

According to my experiences and measurings, Quantum SCSI drives work fastest with Mega STE internal adapter. Close to max speed of DMA chip (1250 KB/sec).
I have much faster Fujitsu 10K rpm drive, but it is some 12% slower. Likely ACSI handshake is best with Quantum somehow.
Buying SCSI drives on E-bay is not the smartest thing, as it is with many other... In fact, if you are lucky may get some SCSI drive even for free - when they clean out offices from old computers.

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Re: Reverse engineering of some ICD Link adapter

Postby alexh » Tue Aug 17, 2010 9:15 pm

SofiST wrote:There is still demand for ACSI/SCSI adapters

Is there? I thought that the demand is only because they can be cheaper than ultrasatan. My second hand ones bought over the last 5 years were a LOT cheaper. Perhaps 20% of the Ultrasatan cost.

SofiST wrote:SCSI with good adapter is still faster

Is that true of Ultrasatan? I know the original one was slow but I thought that the sequel was getting close to the theoretical transfer speed?

SofiST wrote:I don't agree that SCSI drives in range 1GB-30GB are rare now.

My thinking was unless you run MinT you cannot use the majority of larger drives can you? I thought that there were limitations (even with the BigDOS patch) to the number and size of partitions? I'd be curious to know the true details. I think the maximum usable storage is 64GBytes (32&2GB)? But 32-drive icons on your desktop is hardly usable?

(I'm sure you already know all this)

SofiST wrote:The point is what to do when you have such drive and Atari, but no adapter, or it is broken ?

You use the tools (that you wrote) to transfer the files to your PC and then onto your SD card? :)

viewtopic.php?f=15&t=17318

On a more serious note. I've looked at both of my "Link" cables and both are moulded plastic, seemingly with no way to open without cutting.

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Re: Reverse engineering of some ICD Link adapter

Postby AtariMega125 » Wed Aug 18, 2010 3:46 am

SofiST wrote:According to my experiences and measurings, Quantum SCSI drives work fastest with Mega STE internal adapter. Close to max speed of DMA chip (1250 KB/sec).


1298 K/S , 14ms average access time is what I just measured from From my Mega STE and an incredible 1438 K/S, 15ms average access time is what I got from my Mega 4 with an Adscsi Micro host adaptor. Identical Quantum Lighting 730S drives in each machine. Software used was Ratehd.prg from ICD. The zip drive gives me around 800 K/S, Older Quantum drives around the same.

:)
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Re: Reverse engineering of some ICD Link adapter

Postby Jookie » Wed Aug 18, 2010 7:53 am

alexh wrote:
SofiST wrote:There is still demand for ACSI/SCSI adapters

Is there? I thought that the demand is only because they can be cheaper than ultrasatan. My second hand ones bought over the last 5 years were a LOT cheaper. Perhaps 20% of the Ultrasatan cost.


The price of UltraSatan depends on the manufacturer, can be less then half of what it has been sold for... And if you can make it on your own, the price would be a lot lower.

alexh wrote:
SofiST wrote:SCSI with good adapter is still faster

Is that true of Ultrasatan? I know the original one was slow but I thought that the sequel was getting close to the theoretical transfer speed?


It's near that... And with applications smaller than 1 MB you won't probably notice the difference when using it (I mean not doing speed test where the difference can be seen in the numbers)
http://joo.kie.sk/ultrasatan/benchmarks.html

alexh wrote:On a more serious note. I've looked at both of my "Link" cables and both are moulded plastic, seemingly with no way to open without cutting.


I got mine disassembled some time ago, it was Link II or Link 97 (I don't remember which one) and all it did contain was one MAX chip (CPLD from Altera) with like 100 macrocells. Everything was done in that, so it would take some logic analyzer and then just some time to figure out the equations it uses...

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Wed Aug 18, 2010 10:25 am

alexh wrote:
SofiST wrote:There is still demand for ACSI/SCSI adapters

Is there? I thought that the demand is only because they can be cheaper than ultrasatan. My second hand ones bought over the last 5 years were a LOT cheaper. Perhaps 20% of the Ultrasatan cost.
SofiST wrote:SCSI with good adapter is still faster

Is that true of Ultrasatan? I know the original one was slow but I thought that the sequel was getting close to the theoretical transfer speed?
On a more serious note. I've looked at both of my "Link" cables and both are moulded plastic, seemingly with no way to open without cutting.


Nice. So, will you sell me one of your ICD adapters for 20% price of UltraSatan ? Or you will look first prices at E-bay ? :mrgreen:

According to tests what DrCoolZic made with different SD cards on US speed is in range of 900-1100 KB/sec. And KB by me is binary KB, so 1.024 decimal KB.

Why you call them 'cables' ? :D

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Wed Aug 18, 2010 10:34 am

AtariMega125 wrote:
SofiST wrote:According to my experiences and measurings, Quantum SCSI drives work fastest with Mega STE internal adapter. Close to max speed of DMA chip (1250 KB/sec).

1298 K/S , 14ms average access time is what I just measured from From my Mega STE and an incredible 1438 K/S, 15ms average access time is what I got from my Mega 4 with an Adscsi Micro host adaptor. Identical Quantum Lighting 730S drives in each machine. Software used was Ratehd.prg from ICD. The zip drive gives me around 800 K/S, Older Quantum drives around the same.
:)


I count KB by binary - as my test programs do. So, your 1298 K/S is practically same as mine 1250 :D

http://atari.8bitchip.info/ahpt.html

That 1438 KB/sec is another reason why I want to make close look to some ICD adapter (is Adscsi Mikro ICD at all ? - little confused with those types) . Fact is that in Atari DOCs stays about DMA speed of 10 megabits/secons, what makes 1.25 Mbytes. And I couldn't get more on my Mega STE and internal adapter. So, I guess that Adscsi adapter uses some different data transfer - maybe synchro instead hand-shaking ? Btw, Jookie got some even higher results - see at his site.
Just to note that there is no any article about how that speed over 1250KB/sec can be achieved. (Correct me if I'm wrong).

Of course, we could be little smarter if people would be more contributive, and do some more tests ...

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Wed Aug 18, 2010 11:38 am

It would be good to clarify all ICD adapters - what they can. Of course most interesting is max accessible hard disk space + related with it - can it handle CD ROM devices too.

http://www.icd.com/atari/

I guess that only AdSCSI Micro is limited to 1GB ?
According to photos, actually AdSCSI ST is interesting for copiing it - it consists mostly from GALs.

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Re: Reverse engineering of some ICD Link adapter

Postby wongck » Wed Aug 18, 2010 11:55 am

SofiST wrote:Fact is that in Atari DOCs stays about DMA speed of 10 megabits/secons, what makes 1.25 Mbytes.


Great stuff... does this also applies to the Falcon & TT?
TT seems faster then Falc SCSI.
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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Wed Aug 18, 2010 2:08 pm

wongck wrote:
SofiST wrote:Fact is that in Atari DOCs stays about DMA speed of 10 megabits/secons, what makes 1.25 Mbytes.

Great stuff... does this also applies to the Falcon & TT?
TT seems faster then Falc SCSI.


Falcon SCSI is faster, by mine measures max speed is about 1.7 MB/sec. On TT is more, but let some TT user tell us it ...
Actually, TT has special SCSI controller chip, while by Falcon it is integrated in DMA chip. And accordng to AHDI sources it has HW bugs - at every DMA transfer (sector ?) end needs to transfer some amount of bytes (16 ?) in single-byte mode. Without it, speed would be likely over 2MB/sec.
And I have some ideas that maybe some STE revisions have faster DMA chip than those in STs and older STEs ... That could explain high speeds too.

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Wed Aug 18, 2010 2:12 pm

I found AdSCSI ST manual at dev org. According to it : AdSCSI ST and AdSCSI Plus ST can over 1GB. Can handle removables, so very likely SCSI CD ROM drives (didn't see it specifically there). No parity support. But replica should have it (1 cheap IC plus, or solved in CPLD). And no SCSI arbitration, but I think that it is not mandatory, and for sure is not easy to solve with GALs.
According to layout pic, AdSCSI ST has 8 x 20 pin chips, probably all 8 are GAL20V8 .

AdSCSI_ST.gif
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Re: Reverse engineering of some ICD Link adapter

Postby 1024MAK » Wed Aug 18, 2010 2:44 pm

SofiST wrote:According to photos, actually AdSCSI ST is interesting for copiing it - it consists mostly from GALs.

So maybe if owners do not wish to part with them, at least take some close-in high quality high resolution pictures of the top and bottom of the boards... :mrgreen:
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Re: Reverse engineering of some ICD Link adapter

Postby 1024MAK » Wed Aug 18, 2010 3:17 pm

Okay, here are some pictures of the ICD The Link 2...
BTW the plastic case is made up of two pieces of plastic that clip together.
The red "dot" of the i in Link is a red LED, it shows up as a red blob on the picture of the PCB track side.
ICD The Link 2 - top case.jpg
ICD The Link 2 - bottom case.jpg

The last two are rather large. To properly view these two pictures, download them, use the scroll bars, or click on them then reduce the view size on your browser (eg in FireFox use [Ctrl] and [-], use [Ctrl] and [0] (zero) to reset) :D .
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Re: Reverse engineering of some ICD Link adapter

Postby DarkLord » Wed Aug 18, 2010 3:35 pm

SofiST wrote:I found AdSCSI ST manual at dev org. According to it : AdSCSI ST and AdSCSI Plus ST can over 1GB. Can handle removables, so very likely SCSI CD ROM drives (didn't see it specifically there). No parity support. But replica should have it (1 cheap IC plus, or solved in CPLD). And no SCSI arbitration, but I think that it is not mandatory, and for sure is not easy to solve with GALs.
According to layout pic, AdSCSI ST has 8 x 20 pin chips, probably all 8 are GAL20V8 .


Someone else can correct me if I'm wrong, but I think SCSI bus arbitration is important.

Well, important if you are planning on burning CDs. I'm pretty sure that my Yamaha
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Re: Reverse engineering of some ICD Link adapter

Postby AtariMega125 » Wed Aug 18, 2010 4:05 pm

SofiST wrote: AdSCSI ST and AdSCSI Plus ST can over 1GB. Can handle removables, so very likely SCSI CD ROM drives (didn't see it specifically there). No parity support.


The later versions of AdSCSI and all ADSCSI Plus cards(I think) handle parity. The ADSCSI micro definitely doesn't . I use my ADSCSI Plus with an external zip drive at present and I have tried it with other scsi drives big and small and there have only been a few failures and I have been able to daisy chain 2 SCSI drives to it's SCSI output.

And I just took the ADSCSI Plus out of the case and it has 5 socketed palce16v8h chips, 2 soldered 74240s, 1 soldered 74244, 1 soldered 74374, and 1 soldered 74245 chip. There is one more 14 pin dip in a socket that is OKI M8301 and this looks like part of the realtime clock ciruit.

I took pictures which I will post later.
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Re: Reverse engineering of some ICD Link adapter

Postby 1024MAK » Wed Aug 18, 2010 5:47 pm

AtariMega125 wrote:I just took the ADSCSI Plus out of the case and it has 5 socketed palce16v8h chips, 2 soldered 74240s, 1 soldered 74244, 1 soldered 74374, and 1 soldered 74245 chip. There is one more 14 pin dip in a socket that is OKI M8301 and this looks like part of the realtime clock circuit.


The 74240's are inverting buffers, the 74244 is a non-inverting buffer, the 74245 is a bus transceiver, the 74374 is a D-type flip-flop (or data latch). All these have 3 state bus outputs and are standard 74 TTL chips :D .
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Re: Reverse engineering of some ICD Link adapter

Postby alexh » Wed Aug 18, 2010 7:54 pm

SofiST wrote:
alexh wrote:My second hand ones bought over the last 5 years were a LOT cheaper. Perhaps 20% of the Ultrasatan cost.

Nice. So, will you sell me one of your ICD adapters for 20% price of UltraSatan ? Or you will look first prices at E-bay ?

Why would I buy something if I didn't want it? I bought mine from ebay. Wait long enough and bargains come along.

SofiST wrote:Why you call them 'cables' ? :D

Because I think of them as "the cable" which goes between the Atari and the SCSI hard drive.

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Re: Reverse engineering of some ICD Link adapter

Postby SofiST » Thu Aug 19, 2010 7:58 am

alexh wrote:...
Why would I buy something if I didn't want it? I bought mine from ebay. Wait long enough and bargains come along.
SofiST wrote:Why you call them 'cables' ? :D

Because I think of them as "the cable" which goes between the Atari and the SCSI hard drive.


Well, I will not wait years, for sure. Fact is that usual prices now are about 100 dollars or Euros. Please, try with some more useful comments. Lottery is not the topic here :mrgreen:


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