520 STE refusing HD-floppy upgrade

[mib5150]

A few years back I bought a kit for upgrading any Atari from DD- to HD-floppydrive. Yesterday I asked a friend to help me install it in my 520STE.

The description was very sparsely written, and we tried our best to understand it.

Finally the entire project fell on the fact that it asked us to pick up a 16Mhz signal, and we failed to find such a thing. We found 8 Mhz and 32 Mhz. Oddly enough the STE has a jumper to allow TOS2.06 to format HD-floppies, but WHAT ABOUT the rest of this HD-floppy business inside the computer? Completely missing. :-/

So, does anybody have experience of how to install a HD-floppydrive in a 520STE?

Update: Right now my friend told me on irc that he now have found some documentation about getting a 16Mhz signal on the GST (pin 52), but we'd like to hear about your experiences anyhow!

/ Lars

[alexh]

You only need the 16MHz signal if you don't have the AJAX disk drive controller chip.

[flai]

You only need the 16MHz signal if you don't have the AJAX disk drive controller chip.

Well, I have checked Lars STe and it's not the AJAX in his machine, it's the WD-chip.
So I guess the problem stays unsolved?

[DarkLord]

I don't know if it would help or not, but you can read Ralcool's message thread here:

http://www.atari-forum.com/viewtopic.php?f=15&t=18847

Long thread, but he does get into a HD upgrade for ST's. You could also post
directly to the thread, asking him what he thinks. He's got a lot of experience
with this subject now...

[MiggyMog]

Also check these:- http://atari4ever.free.fr/hardware/drives.html

[ralcool]

My experiance with the STE is limited (read as: I touched one once and let out a small but imperceptable fart)

I understand that although a 16mhz clock is obtainable from the Pin #52 of the GSTShifter... aparently it is rather weak.
That is according to the several docs I have for homebrew/DIY HD mods.

Regardless, some form of HD switching circuit is required, and most offerings contain their own 16mhz crystal.
STE's have NO wiring from the floppy cable pin2 (HD detect) to anything on the board.

The MegaSTE on the other hand does, and the (legendary?) U402 PAL chip has a 16mhz feed into it,
plus the HD detect (pin2 of the Floppy drive) and clock line to the WD chip (Pin 18) also go to/from that chip.

As for the Ajax, it is a drop in replacement for the WD, and the best I know is that it is simply a modern version built to handle 16mhz reliably.
It contains no extra pins or clock doubling circuitry to achieve HD.

I have an Ajax in my STFM- and it functions identically to the WD. As far as I can tell.


Hope this helps.
ST.

[flai]

Well here's an update to the problem:

I've made a mod to my STE combining the regular 74LS151 with a 74LS74 to divide 32MHz (from the clock input on the GST Shifter pin 53) into 16 and 8Mhz.
I've made all this on a scrappy veroboard for now before making the real PCB's, so it looks terrible but does the job

BUT, i've managed to get the HD detect from my Sony-drive to work.
When a DD is inserted the clock out to the FDC is 8Mhz and when i insert a HD it changes to 16MHz, no problem.
No troubles at all with the DD floppies, I can read them and format them with no problem at all.
But, it doesn't want to read the HD floppies and I can't format them either. So obviously something's wrong...

I've measured the clock signal with my oscilloscope and the pictures shows the 8MHz vs 16MHz.
The 16MHz is slighty weaker compared to the 8Mhz, but the 32MHz was even weaker then the 16MHz so, dunno if thats the problem...

One thought I had in mind when I looked at my oscilloscope is that the 16MHz signal seem to inverted compared to the 8MHz signal, could that be a problem perhaps?

PLEASE, if anyone (perhaps you Ralcool ) have any ideas what's wrong, please let me know!

8Mhz.JPG

16Mhz.JPG

[christos]

Are you using tos 2.06? Older TOS doesn't have the hd floppy option.

[ralcool]

Have you also changed the floppy drive step rate to 6ms?

When you run the controller at 16mhz the normal step speed is halved. So 3ms is normal and is now 1.5ms

Most drives can't handle a pulse that short, wo we use a software 'patch to set to 6ms.

STEP6M.zip

I'm not 100% sure if the program is STE compatible, but your will hear the difference if it works.

Also try this one too, it came with my original HDmod I bought long long ago. Same result. 6ms step.

Elco_HD.zip

Should sort you out.

Finally, this utility will format HD disks.

FCOPYPRO.rar

ST.

PS, The signal looks inverted since its gone though another stage of the divider. Not an issue.
Remember some mods run an independant crystal, not synced to anything!

Oh, and the clock looks nice and clean. Goodjob.

[flai]

Thanks for all the answers

It's TOS 2.06 and i have closed jumper J6 on the motherboard.
I actually downloaded the step6ms.zip and tried that, but perhaps I made something wrong with it. I'll try the other one u suggested and perhaps I will have more luck with that

I used the fcopypro when I tried, but is there any special options to be made in the program? Or just 3,5HD? Cause I noticed that the steprate could be altered in the options...

Thanks for all the help!

[flai]

Here's an update:

I've tried both the Step6ms.prg and the ElcoHD.

With the step6ms in an auto-folder on a DD it says something like "Drive B is set to 6ms" and then it stalls and won't go further. Annoying or what?!

With the ElcoHD it turned out like this:

I went through the document about how to configure the program and set the Drive A like this: A,6,H,H,3,M,8 (have also tried like this A,6,H,L,3,M,8).
But everytime it turn out like this pic:

atarifel.jpg

So, I guess there is still something wrong...

Any ideas?

[ralcool]

Ahh, Right, I noticed the same screen just now trying it myself . This driver finds the TOS 2.06 HD cookie, and aborts.

Now we know you are using 2.06 the drivers are a waste of time....

With 2.06 the step is set to 6ms anyway... so the problem is elsewhere.

Interesting. Where is this little gremlin....?

Thinking, thinking.....

ST>

[flai]

Yeah, I'm really scratching my head on this one...

Perhaps I should try another drive, perhaps somethings wrong with it...

It shouldn't be the clock signal anyway, I measured it on FDC pin 18 when I took the pics and as you say they are looking good.
So, the problem must be in something else...

Damn those gremlins

[flai]

And well, here's an update again:

Tried another drive, same problem, so I don't think thats the problem.'

I've taken som e pics on the error message in fcopypro:

fcopy_fault1.jpg

fcopy_fault2.jpg

fcopy_fault3.jpg

Like I said, seems it can't read the disc...

Here's some pics on the veroboard. It ain't pretty, but the signal seems fine:

vb01.jpg

vb02.jpg

[ralcool]

It would be interesting to know if the 'wrong/bad' DMA chip is somehow responsible here. It sits between the WD and the ST's data bus.

It might maybe explain the MegaSTE HD upgrade problem too.

Just thinking out loud.....Are the later revisions less able to handle the 500k+/sec data rate from the FDC chip in HD mode.??....odd, but hey.. who knows....

ST.

[flai]

Is there many different models of the DMA chip?

Well, in my 1040 STE it's markings is:

(Chip nr U300)
C025913-38
PH23-030
9M2 18
(made in plastic and soldered to the motherboard)

1040STE_DMA.jpg

And in my 520 STFM it is:

(Chip nr U31)
C100110-001
Atari 1987
-31 110354-01
8827FKR
(made in ceramics and is socketed)

520STFM_DMA.jpg

Could this be the case then perhaps?

I could try to solder the mod into my STFM instead and see if it works there.
If it does, well then the STE has something BAD (cheap plastic DMA's perhaps?!) on it

[flai]

New update!

I took the mod out of my STE and put it in my STFM.
Took like 10 min to complete the whole thing...

and...


IT WORKED LIKE A CHARM!

But... the STE problem still remains then... Could it be the DMA as you said, Ralcool?
Wouold it be possible to shift the DMA from an STFM into the STE?

[ralcool]

I assume you ran it from 32mhz too in the STFM???

Otherwise Excellent.

It looks like the DMA is soldered into your STE.
Desoldering is a pain best avoided. If you confident, go ahead.
Whack a socket under that DMA chip in the STE too.

Good work Fai.

ST.

[flai]

Yes, I took the 32MHz from Shifter pin 2 (I think it was...)

Desoldering the DMA chip could be a pain in the ass, just as u say, but... I got pretty good tools that I think will do the job.
Just as you say, I will put a socket there instead and then I can easily test different DMA's in the future.

To be continued...

[DarkLord]

Hmm, I couldn't get the HD mod to work in my STacy and the Stacy was
released the same year as the STe (1989), IIRC.

Aside from the high probability that its something I'm doing wrong,
could their be a link?

[ralcool]

Gawd my ST is fragile.

I decided to check which DMA chip I have inserted. Which involves moving it from its generally fixed location.

Removing the FDD + HDD (well move aside while connected)

Then I often find having to put pressure on or reseat the mods before the thing will fire up again.
The TOS/IDE and the Memory board have short pins that don't sit very deep.

There are so many things with sockets/IDC connectors... you never know what has failed.

After all this, my DMA chip is what I thought,

CO25913-38
PH23-030
9J4 94

So a slightly different revision/batch number. (But it did come off an STFM Rev.E. board)
My original chip was the imp C100110-001.

Both worked fine.... Its still worth a try to change- but also consider the possibilty the WD1772 just won't overclock well to 16mhz.
Most instruction do say some just won't... hit and miss...

I was lucky my motherboard had both socketed from the factory..... And buying an Ajax chip was simply because it was available at the time.

ALSO, My ElcoHD kit instructions talk about actually piggybacking a SECOND 7406 chip to U305 in the STE (U14 in ST) . This is to increase write current to the drive.
This IC boosts (and inverts) the control signals from the WD. (The manual does emphasise this is to fix write 'problems' )

The RD (read) & Index lines though go direct to the FDD.

I doubt very much this will help the problem we are having.

Much fun.

ST.

[flai]

After some reading in other threads regarding the "faulty" DMA chip I have come to other conclusions.

Perhaps, like simbo says, there is no faulty DMA's.
Perhaps it's the bad (cheaper) 74-logic that's causing the faults, like he claims it is. (And I believe him! )

I will try to change all my bad (cheap) logic and see what happens, I mean, it can't get more worse, on the contrary, it would be better off anyway

BUT, I can't seem to find any seller of the 74F06 in 14-DIP in Sweden, only the SMD SO-14.
So perhaps I have to make some kind of an adapter to it some how...

Well well, that's it for now...

[flai]

After all this, my DMA chip is what I thought,

CO25913-38
PH23-030
9J4 94

This is the same DMA I have in my STE, and it's what the call "THE BAD DMA" in other threads.
SO, this is proof that it actually ISN'T a BAD DMA cause it seem to work just fine in your ST

Sorry to hear that your ST's so fragile, but I understand... got the same feeling, and I don't have as near many mods in mine as you do

Take care

[ralcool]

Hey Fai,

I don't use any ACSI devices on my DMA, plus the STFM doesn't have the buffer chips used on the ACSI port after the DMA chip.
If my DMA is the 'bad' type.. I am not affected by it. If I used an 'UltraSatan' maybe things might be different.

Any LS type 74series logic, if replaced- should be changed to 74HCTxxx types... CMOS TTL level compatible.

I can sent you a proper 'old' 7406 chip if you want.... will cost you a nice postcard of your area.. . I have two spare.
PM your address, I'll pop one over to you.

I've had another thought, after checking closely STE diagrams vs STs... the ST DMA/WD etc, all run from the system 8mhz clock.

On the STE, The DMA is fed from the main 8mhz, but the WD/FDC controller runs off a seperate crystal, 8.010613mhz... 10KHz higher.
One document I read recently (trying to find it again) suggested that 16mhz is only about within tolerance to run a HD FDD... maybe-like Atari
did- it actually needs to be a touch higher..... I don't know. 20KHz more could be the answer.......?

Surely this couldn't be the answer.

My_STFM.JPG

My ST as of tonight...... running nicely again..... second 68HC000-16 CPU sitting above the original.... for attempting the 32mhz overclock mod.
I think the overclock mod doesn't like what is happening..... getting my head around how the switching logic works to alter it.

Can you pick each mod? (The AT-Speed is currently removed, as is the PS2 mouse adapter. 2.5" HDD is under the FDD)
Remarkable the thing even still works given the amount of corrosion, cuts & changes.....

Cheers...

ST.

[flai]

Hey Fai,

Where did you exactly get "Fai" from?!

Well, it's the crappy 7406 i DON'T want, actually
I wanted a better and faster one instead.

Why do Simbo say that you should use the ACT-model then?
But he said also to reduce the VCC to 3.3V, I think... =)

Dunno if it has something to do with the clock, but hey, somethings wrong and its better not to shut any conclusions out.

Now it's food time! I'll be back