Modified ST hassles

[DarkLord]

yeah, thats it. My attempt to setup the drive for ST use.

If you've cut CTin, then last is to remove the pin2 mod. Just remove that wire.

Attempt to use the drive as DD 720k.

Otherwise,,, its a pure PITA.

Wait, wait, wait...before I do anything, something weird has happened. I was searching the forums
for related topics (just trying to educate myself on this subject) and I found this thread:

http://www.atari-forum.com/viewtopic.ph ... el0#p43854

"Now, the important bit.
Replace the floppy cable. I found that the cable had to be twisted over 180degrees as the connector on the new sony had pin one on the opposite side to the old drives. This is OK becuase the DIL pin connector on the Sony has notches for the floppy connector either way. Also, seperate the floppy ribbon in about three places, so you have four smaller strips of ribbon, this will make rotating the cable over MUCH easier."

So just for the sheer unadulterated fun of it, I flipped the FDC going into the 1.44 drive you sent.

Boom, it will now boot up into 720k mode perfectly. It won't boot up into 1.44 mode though. I was
using the 720k floppy disk with the step program in the AUTO folder. It gave a weird bootup message,
something like 600ms rate has been set for Drive B. That's right, it said Drive B. Well, I tried switching
the 720k floppy out for the 1.44 just to see if it would recognize the change, but it didn't. I also tried
clicking on the Drive B icon, but after swapping floppies it said drive not responding.

So what the heck does all this mean?

[DarkLord]

yeah, thats it. My attempt to setup the drive for ST use.

If you've cut CTin, then last is to remove the pin2 mod. Just remove that wire.

Attempt to use the drive as DD 720k.

Otherwise,,, its a pure PITA.

PS, edit... just thinking, use the ohm mode of you MM and ensure that JC30 link is working.

Not done any changes until I get your response to my post about flipping the FDC.

I did use the MM on the link - looks fine, pegged out the meter. I also checked JC31, just to make
sure it might not be shorted, and it was ok - no reading at all.

Gonna have to go get a couple of hours sleep - I'll check back in and see what you think about the
cable flip and its results.

Thanks!

[ralcool]

You're shitting me.

Yeah, Pin 1 is closest to the the power plug on the Sony drive.... Ala the red striped wire.

Looking at my own cable- its twisted 180*, been so long I didn't even notice.

Things are ok... The driver program is dumb and configurable. On boot it reports defined settings.
The elco driver mentions b: even if not connetced.

ignore it for now.Joyfully we've discovered something..... Pin 1.

Holding the access light on is exactly what a PC does if the floppy connector is on reversed.

And I assume we can now boot 720k from the new 1.44Mb drive without the mod. ?

...... since the reversed connector would have shorted/held pin2 to gnd. retest.

consider this whole process a restart.... Plug it all back in properly and try again.


ST.

[nativ]

Hi,

how easy or not would it be to either use a 1.44 usb floppy via etherNEC? or mod a usb floppy for connecting to drive 'B' port for use as a 1.44?

[spiny]

happy birthday ralcool

[Shredder11]

Yeah Happy Birthday! I was going to post when I saw it on the front page...........35 years young I believe!

[DarkLord]

You're shitting me.

Nope.

Yeah, Pin 1 is closest to the the power plug on the Sony drive.... Ala the red striped wire.

Looking at my own cable- its twisted 180*, been so long I didn't even notice.

To add insult to injury (and a product of my poor eyesight closeup), there is actually a
triangle stamped into the 1.44 drive case, exactly where pin 1 is (when I flip the FDC).

I hadn't noticed it before...

Things are ok... The driver program is dumb and configurable. On boot it reports defined settings.
The elco driver mentions b: even if not connected.

ignore it for now.Joyfully we've discovered something..... Pin 1.

Holding the access light on is exactly what a PC does if the floppy connector is on reversed.

Ahhhhhhhh..... So I assume when the time comes and we need it, we can configure the step
program for Drive A.

And I assume we can now boot 720k from the new 1.44Mb drive without the mod. ?

...... since the reversed connector would have shorted/held pin2 to gnd. retest.

consider this whole process a restart.... Plug it all back in properly and try again.

ST.

Right, tried it just now and with the paperclip jumper in place, and the FDC reversed,
the 1.44 floppy drive will bootup in 720k mode.

If I remove the paperclip jumper and put the mod back in, with the FDC reversed, it also
boots up in 720k mode.

With the mod in, or the paperclip jumper in place, doing the MM test on pin2 of the FDC (now
this is the pin2 that I cut, mind you) and the FDC reversed, I do get 5v at pin2 whenever there
is no floppy in the drive, or a 1.44 floppy disk in the drive. I get a "nudge", very small reading
(almost none?) when a 720k floppy disk is in the drive.

All of the above is with the 1st header on the FDC plugged into the 1.44 floppy disk drive, just
reversed. I tried the 2nd header on the FDC, just for fun, with the FDC reversed, and the STacy
either 2 bomb crashes, or I get a garbled screen (assuming a crash here as well), with all floppys.
(and it fails the pin2 volt test setup like this)

Trying to sum it up then, what works is with the FDC reversed, 1st header, paperclip jumper in place
or Mod in place, 1.44 floppy disk drive, 720k floppy disk in, and it boots up just fine. Pin2 voltages all
show what you said to expect, with this setup.

So what's next?

[wongck]

I think flipping over the cable - the effect is like selecting device 1 instead of device 0.
ST select device 0 for floppy.
IBM select device 1 for floppy.
To have back the orginal unflipped cable, you need to make your floppy drive response to drive 0.
Look for some guides in the hardware guides section.

gee... I am typing off my head, so you better check those guides.

[DarkLord]

I think flipping over the cable - the effect is like selecting device 1 instead of device 0.
ST select device 0 for floppy.
IBM select device 1 for floppy.
To have back the orginal unflipped cable, you need to make your floppy drive response to drive 0.
Look for some guides in the hardware guides section.

gee... I am typing off my head, so you better check those guides.

Well, its already there - Its a Sony, so its "SEL0, JC30" and "SEL1, JC31".

Ralcool already had done that part, switching the resistor from the 1 position to 0.

[ralcool]

Thanks for the Birthday greets guys. Shucks

As for our saga, sounds good I think.

You're shitting me.

Nope.

Yeah, Pin 1 is closest to the the power plug on the Sony drive.... Ala the red striped wire.

Looking at my own cable- its twisted 180*, been so long I didn't even notice.

To add insult to injury (and a product of my poor eyesight closeup), there is actually a
triangle stamped into the 1.44 drive case, exactly where pin 1 is (when I flip the FDC).

I hadn't noticed it before...

Things are ok... The driver program is dumb and configurable. On boot it reports defined settings.
The elco driver mentions b: even if not connected.

ignore it for now.Joyfully we've discovered something..... Pin 1.

Holding the access light on is exactly what a PC does if the floppy connector is on reversed.

Ahhhhhhhh..... So I assume when the time comes and we need it, we can configure the step
program for Drive A.

And I assume we can now boot 720k from the new 1.44Mb drive without the mod. ?

...... since the reversed connector would have shorted/held pin2 to gnd. retest.

consider this whole process a restart.... Plug it all back in properly and try again.

ST.

Right, tried it just now and with the paperclip jumper in place, and the FDC reversed,
the 1.44 floppy drive will bootup in 720k mode.

If I remove the paperclip jumper and put the mod back in, with the FDC reversed, it also
boots up in 720k mode. Yay!!!

With the mod in, or the paperclip jumper in place, doing the MM test on pin2 of the FDC (now
this is the pin2 that I cut, mind you) and the FDC reversed, I do get 5v at pin2 whenever there
is no floppy in the drive, or a 1.44 floppy disk in the drive. I get a "nudge", very small reading
(almost none?) when a 720k floppy disk is in the drive.

All of the above is with the 1st header on the FDC plugged into the 1.44 floppy disk drive, just
reversed. I tried the 2nd header on the FDC, just for fun, with the FDC reversed, and the STacy
either 2 bomb crashes, or I get a garbled screen (assuming a crash here as well), with all floppys.
(and it fails the pin2 volt test setup like this) This part is wierd, but I'll ignore it.....

Trying to sum it up then, what works is with the FDC reversed, 1st header, paperclip jumper in place
or Mod in place, 1.44 floppy disk drive, 720k floppy disk in, and it boots up just fine. Pin2 voltages all
show what you said to expect, with this setup.

So what's next?

Sounds like its all working. Lets run the driver (or the one I've included in this post), and insert a formatted 1.44Mb disc.

So,
You've booted the new 1.44Mb drive with the mod connected with a 720k disc. Excellent. Lets add a driver.

STEP6M.zip

Its even simpler.... just run it... auto or anytime. (ElcoHD has a inf file located with it, and its editable... be worth checking what I wrote)

Now insert a 1.44Mb disc, and check its properties. highlight a: and 'show info'.. Behold 1.44Mb goodness.

Crack a cold beer. Tape them wires up, and hot glue the mod somewhere tidy. Job done.

Copy some files from a RAM disk or HDD and test it out to capacity.

Cheers,

ST.

[ralcool]

Hi,

how easy or not would it be to either use a 1.44 usb floppy via etherNEC? or mod a usb floppy for connecting to drive 'B' port for use as a 1.44?

Given that NETusb? device with USB mass storage mode is now working....(aparently)....

Either a: .... why bother. USB drives much larger.
b: .... a driver would likely have to be written for its usb port to run a floppy.

And less work to mod a regular FDD for external use- although the usb fdd cases now look pretty tight.

Biggest hassle in using or building an external floppy for an ST- is getting the damn plug for the back. I've used the same one for like ever.

Years ago, I built my first and only floppy drive cable- sometimes seen in my pics- which also had a edge connector just like a PC FDD cable.

I ran an external 1.2Mb HD 5 1/4" floppy drive for transfering WordPerfect files from our school computers, and loaded them into the C-16 286 emulator.

I do believe you ask a good question, Could the NETusb be programmed to include 1.44Mb FDD support via its USB port. How hard can could it be? Joska?

Cheers,

ST.

[Dal]

Biggest hassle in using or building an external floppy for an ST- is getting the damn plug for the back. I've used the same one for like ever.

Agreed - a while ago there was someone selling these cables on Ebay. Had the large 14-way DIN connector either end for something like £10 or so.

I bought one and lopped it in half to make a cable for my externally housed HxC emulator. So at least I have a spare in the parts bin just in case.

Only way of getting a connector is by salvaging one from an old external floppy drive I think now. You can still make the external floppy drive usable by putting a readily available 15-way D-sub connector on the end.

So make a short converter out of the 14-way DIN connector and a 15way female D-sub that you leave in the back of the ST, then for any external FDD's/HxC's you have, simply fit a 15way D-sub male to the end of it.

If enough people do this, then there should be plenty of 14way DIN plugs to go round for everyone. Just a thought?

[Dal]

... if people are interested, we could use the wiring that I used for my HxC to keep everything 'standard' and interconnectable? I'm salvaging the wiki from December at the moment. Once I have it working, I'll transfer the article to the live one and link back here for reference.

*EDIT* The wiki article is here. Look at Step 5 and the section titled "Wiring the Peripheral Cable"

[DarkLord]

Thanks for the Birthday greets guys. Shucks

As for our saga, sounds good I think.

Sounds like its all working. Lets run the driver (or the one I've included in this post), and insert a formatted 1.44Mb disc.

So,
You've booted the new 1.44Mb drive with the mod connected with a 720k disc. Excellent. Lets add a driver.

STEP6M.zip

Its even simpler.... just run it... auto or anytime. (ElcoHD has a inf file located with it, and its editable... be worth checking what I wrote)

Now insert a 1.44Mb disc, and check its properties. highlight a: and 'show info'.. Behold 1.44Mb goodness.

Crack a cold beer. Tape them wires up, and hot glue the mod somewhere tidy. Job done.

Copy some files from a RAM disk or HDD and test it out to capacity.

Cheers,

ST.

Okay, I can't get into the room where my Mega ST is right now (oldest son is asleep in there, works nightshift), to transfer this version of the step program to floppy to try it out.

It is different than the one I have here now?

Because the one I have here now makes no difference in reading a 1.44 floppy disk. I can boot up, with the mod in place, and the 1.44 floppy drive, with a 720k floppy disk in, with the current step program I have (not the one in this post) in the AUTO folder, and all goes well. When I switch the 720k floppy disk out for the 1.44 floppy disk and attempt to access it, I just get a "Drive x not responding" error message.

Thanks!

[ralcool]

Ok.

The different step rate software shouldn't make any difference. Just something to try.

Curious why you need the Mega to transfer the file to floppy?.... Are you using PC to access the internet?

I know we've checked now pin2 for voltage changes inserting a DD disk. Have you checked again at pin 10?

Now that we know 8mhz is getting to the WD1772, it would be nice to know if it is truely switching to 16mhz.

Tricky without a modern MM to actually tell us...BUT.... you should see a tiny voltage change on pin 5 (CLKout) as you click in and out a DD disk.
Then we have a hint. The mod actually defaults to 16mhz output... and is triggered low/8 mhz by a DD disk.

The fact a DD disk works- means the mod and drive together are doing something. Great stuff.

Hopefully our 16mhz source is ok. Maybe we should relocate it?

Do we know the 1.44Mb disc is ok?, maybe we should try to format it in the STacy.

I'll dig up the decent formatting program I posted here somewhere.

Cheers,
ST.

[DarkLord]

Okay, same program then.

My main comp is a Linux box - no floppy drive in it. I burn the step program to a CDr, take it to my Mega ST, which has a CDRW, and copy it to a DD floppy on the Mega ST. My way of transferring stuff to my lower end Atari's. If I had my Ultrasatan hooked up, I could transfer that way, directly to the STacy.

I'll check pin 10 again. BRB.

Okay, booting up with the mod in place, 1.44 floppy drive hooked up, FDC flipped, 1st header, 720k floppy in, at the desktop - MM black to gnd, red to pin10 on the mod - gives 0 or nearly 0. Switching out the 720k floppy for a 1.44m floppy - with no floppy in, gives what appears to be 5v, with the floppy in, gives what also appears to be 5v.

Okay, now checking pin5 - with the same setup as above, I get a reading on pin 5 with the 720k floppy in, and an even smaller, but not by much, reading with the 1.44 floppy disk in, or no disk at all in.

I've tried a couple of different 1.44m disks I had lying around here - so one of them should be good.

Something odd, just occasionally, when I pop the 720k floppy disk out, the drive sounds like its continuing to "read". Putting the disk right back in stops it.

EDIT: Okay, it just got a little weird again. I was playing around, retesting some of the voltages, going by the tests you said to do and the wire leading to pin18 of the WD1772 (the one that you have to cut and lift the pin leg from the MB) came loose. No problem, I thought, so I just cleaned it a bit and reattached it. Booted back up, and it seems fine, but now whenever I remove the 720k disk to try the 1.44m disk, the mouse freezes up and nothing will get it back unless I power down and back up. This is with the mod in place. If I remove the mod and use the paperclip jumper, it doesn't freeze up. Ugh, my brain hurts - any ideas? Thanks.

[ralcool]

Yeah same type of program, just that it just sets step to 6ms for both drives always.

Can you tell if the step rate is changing on boot up with the boot disk?

Because the drive will groan differently after the patch loads- indicative of the slower step pulse.

Until the step rate is lowered, it won't read 1.44Mb.

ST.

[DarkLord]

Yeah same type of program, just that it just sets step to 6ms for both drives always.

Can you tell if the step rate is changing on boot up with the boot disk?

Because the drive will groan differently after the patch loads- indicative of the slower step pulse.

Until the step rate is lowered, it won't read 1.44Mb.

ST.

Will try to figure out if its changing or not - but either way, it shouldn't cause the mouse to lockup
should it?

EDIT: Okay, just for the fun of it I hooked my Ultrasatan back up and copied the step program into its
AUTO folder. Now it doesn't rely on being run from any floppy drive. I know you said it was good as long
as it ran from anywhere but I was just experimenting.

Makes no difference though, as expected. Booting from the Ultrasatan, step prg in the AUTO folder, mod
in place, 1.44 drive, 720k floppy, boots up. Pop the 720k floppy out, and immediately the mouse freezes.

All of the above except removing the mod and using the paperclip bridge, pop the floppy out, mouse does
not freeze, but it (of course) doesn't recognize a 1.44 floppy.

Okay, ready for the next round...

[ralcool]

Oh boy.

Lots going on with you guys... great to see. HD mods are working out harder than expected..... who knew??

I've been playing too. Question: "How to disable the existing on board 68000 to let a piggyback socketed 16mhz version run instead?"

After some playing- not too hard.

First goal was to allow the second 68HC000-16 sit on the original cpu, in a disabled state and run the ST normally.

Tried using the halt pin to gnd... no dice... What about reset instead. YES!!!

OK, Lets disable the original cpu and run the new one... Deep breath- cut a trace near the cpu pin 18 (reset), and then ground the pin on the cpu with a link wire to gnd.

Feed the new cpu with reset from a nearby via... voila... it works. (And also replace the reset input on the ROMIDE I/F... minor issue)
Test ST. Works fine. Phew.

Why am I doing this... I'm trying to feed the overclock mod with 32mhz instead of 16..... A higher rated cpu has a better chance of success.

Ok, lift a pin from the 74HC74 that normally takes the 16mhz from the shifter, and replace with the 32mhz signal that is also on the shifter chip.

Now the answer you've all been waiting for.....

Gembench 4.03... CPU test...
8mhz = 100%
16Mhz = 129%
32mhz = no dice... sorry.

Does it work- no, it hangs as soon as my mod switches to high speed. Bugger. More work to try. I guess even the higher speed spec cpu just can't take it.
All that work for nothing. (I'm going to check if perhaps the 74HC74 on the mod is out of spec at this speed)...

Never give up.

ST.

edit: So I tried a super high speed 74AC74 chip on the mod from my parts (even though the HC is rated to over 50mhz), and still no good.

[DarkLord]

Nice to see you "back at it".

As always, looking forward to your tests/results.

PS Be interesting/entertaining to see if you can make
my T28 accelerator board obsolete!

[wongck]

68HC000-16

Can these be OC up 200% ?
I think if you can get 50% increase in clock speed that would be already great.

[ralcool]

Hey Darklord, What is the CPU on the T28 actually rated at.. .I assume its a 16mhz chip (I'm digging around for a post from you showing a pic of the mod)

I'm wondering if they topped out at 28mhz as being the max overclock for the old 68000.....?

Can't see it ever being obselete since your cpu can run full time @ high speed vs this mod using a switching system. 8/16..etc
plus it has a 64k cache too IIRC.

Cheers..
ST.

[DarkLord]

Hey Darklord, What is the CPU on the T28 actually rated at.. .I assume its a 16mhz chip (I'm digging around for a post from you showing a pic of the mod)

I'm wondering if they topped out at 28mhz as being the max overclock for the old 68000.....?

Can't see it ever being obsolete since your cpu can run full time @ high speed vs this mod using a switching system. 8/16..etc
plus it has a 64k cache too IIRC.

Cheers..
ST.

Here is a screenshot of my T28:

SAM_1541B.jpeg

Here is text from an ST-Report "back in the day". Seem there was a T36
as well!:
-----------------------------------------------------------------------------------------------------------------------
"One of the best compatable accelerator boards I know of and use is
the T28 and T36 series. They are basicly a 68000 running at Txx, so
a T28 is a 28Mhz and the T36 is a 36Mhz version. Most ST's except the
T28 and a few will except the T36, but some mods are normaly required.

These board's are designed for the STFM, Mega ST and STE. There is no
mention of the Mega STE being able to use the STE's board, you would
need to contact the distributor and ask them if it's possable to fit.

They also have a 64K fast cache memory on board which can be switched
on the fly and the speed of the system can be reduced back to the
normal 8Mhz by switching a switch and reseting the computer. As a
68000 is used there is NO compatability problem's with program's or
hardware.

My STFM has a T28 in it and this increases the speed of the CPU to 300%
Gembench) and 337% if I install GEMRAM and other util's which put TOS
in memory. (Don't ask me why this should increase the CPU, I think
it's just gembenches multiply test's.)

To install these board's your simms MUST be 100nano second's or faster
as although the buses stay at 8Mhz they have a higher demand put on
them and the memory HAS to keep up.

The T board's are also compatable with Cubase and Notator Logic, these
programs use critical timed event's and with complete compatability
with the T board mean's MIDI user's get that extra speed neede when
editting there work.

There are also the PAK 68/3 accelerator boards, these are 32Mhz 68030
boards and have 32K cache with 32bit wide TOS. There is also an
optional FPU chip and it is possable to have the board's running at
40Mhz and 50Mhz!!

Minimum TOS for these board's is 2.06, 3.06 is recommended. The
speed by gembech is 775%. This is just over twice that of the T
boards. However the price for twice the speed is TWICE the price!

Also being a 68030 CPU makes some program's cripple quickly so some
oftware is inevitable. However your machine would be heading along the
Falcon's 68030 chip set and some of the newer program's would run
happily on a PAK board.

There is a software accelerator called NVDI and this can REALLY speed
up the screen display. For example my ST at normal 8Mhz has 100% CPU
and 100% Graphics, With a T28 AND NVDI installed (+ utils) The CPU is
337% and graphics is at 1057%. YES, that's over TEN times faster
screen updates! And with a cool CPU running 3.5 times faster, your ST
becomes a dream machine.

Hope this is of interest."
-----------------------------------------------------------------------------------------------------------------------

HTHs.

[ralcool]

Thanks for that. So it is a 16mhz cpu overclocked.

While googling 68HC000 limits, I came across Joska's site (again), and he mentioned his Falcon (-16) cpu could handle 36mhz without
too much trouble.

I'm thinking my mod circuit isn't designed to cope somehow. My new frequency counter (although limited to 30mhz) doesn't want to
read even 32mhz directly from the shifter, much less what the mod is doing.

I'll have to hookup my PC based 'scope to hopefully see what signals are being generated.

More playing to go.... I'm convinced the cpu should handle the situation now.

On a different note- I had to swap my GLU chip last night too- I have been getting very strange glitches in the video display when the Lascan is enabled.
The glitches were much reduced if the 16mhz was disabled while running in Overscan... I was like WTF?..... changing the GLU chip somehow cured it.
Dunno what is going on there.... but all is well again. Old parts running outside of tolerance is the only explaination for now.

I have fitted a 220R current limiting resister on the Lascan DEout line in case the logic is overdriving the ST.

Never a dull moment.

Cheers..

ST.

[wongck]

"One of the best compatable accelerator boards I know of and use is
the T28 and T36 series. They are basicly a 68000 running at Txx, so
a T28 is a 28Mhz and the T36 is a 36Mhz version. Most ST's except the
T28 and a few will except the T36, but some mods are normaly required.

WOW...
May be they build things better last time.
That's really over 200% OC.