Modified ST hassles

[ralcool]

Hey all.

Update for things....

Parts are still trickling in. I've ordered new pcbs.. I found some photo resist in a can...which largely hasn't worked- either my developer liquid is old and useless- or I am.....

The pcbs with decent and fresh coatings should solve the problems. (At least the pcb masks have printed perfectly)

My new gal /eeprom programmer still hasn't arrived- we are having a long weekend in OZ so maybe it will arrive soon next week.

I am now TRYING to create a version that a 68881 chip will fit, but its NOT easy. (Routing tracks), And locating simple Boolean GAL assembly software is slightly hard than you'd think.
(Thanks to Shredder11, I've registered at 'Petari's site, and awaiting a response... waiting....)

I need to generate a chip enable signal- and would like to use a GAL to do this. Since the address lines will already be connected for IDE decoding, its only a matter of creating a boolean equation for the 68881 CS/CE line...., and a few extra others (FC0/1,LDS,UDS...to the spare 4pins on my header socket). Simple, yet very tricky to wire up.

I may yet revise a incomplete CPU mounted IDE PCB I have created on Popsels design. (But larger, and containing TOS roms, IDE, 68881- and if at ALL possible a RTL8019 chip....) One mega upgrade board! This sucker may end being the first double sided board I've ever made.

(If you wondering WHY.. well I have a 68881, a loose RTL chip, spare 72pin simms, various ROMS, plus a desire to learn GAL programming- a GAL22v8 should cope.....)

BUT!!!
Before ANY of THAT, I just really want to finish what I've started. (I've got chips and sockets everywhere, and nowhere to put them!)

Hope you're enjoying the blog/thread/story of the bored ex-tech. (Who only barely learned to read some code, and likes interpreting schematics)

I simply thought some would like to know what I'm doing, instead of just leeching as a guest. I'm NOT trying to impress anyone. This is my hobby- playing with electronics.

I hope I have helped some others here.

Sean

[Shredder11]

Thanks Sean, looks like you are about to create the mother of all ST machines! If you do manage the multi chip CPU mounted board, I will want one too! (quite serious about that by the way!).

I've just ordered and payed for the Hydra (NETUS-Bee), so that will be something to get my head around once it arrives. Oh and I am waiting for the HxC Floppy emulator board to arrive too! Up until September 2008 all I had was my trusty OLD 1040STE with TOS 1.06, a MIDI OUT on the modem port and a 4MB upgrade. Now I have 3x 4160STE and 2x Falcon 030 along with an amazing array of upgrades and addons! Where will it all end I ask myself!

[ralcool]

http://cgi.ebay.com.au/3-5-1-44MB-USB-S ... 439ed27c81

I've been looking at these emulators too.. Would make an excellent 'B' or replacement A drive.

I bought that plcc socket plug you found too. So I'm looking again at the blitter socket to play with.

[spiny]

>Hope you're enjoying the blog/thread/story of the bored ex-tech.

I certainly am please keep posting

[ralcool]

An early peek at the incomplete pcb for rom mounted; ide / fpu / flashable roms.

Just finshed tracing 99% of the lines. Just need to insert a 20v8 gal (replace 16v8). Plenty more work to finish off... This is tonights boredom outcome.
Not very pretty yet, but the data, power, address lines are ready. Plus many others too.



It sucks how when running a 68881 in 16bit mode, you have to wire the upper 16bits (D16-31 to the lower D0-D15) What a nightmare!

[snoopy]

I really enjoy reading this (though my level of technical knowledge is way beyond anyone who has commented so far). Keep up the good work!

[1024MAK]

http://cgi.ebay.com.au/3-5-1-44MB-USB-S ... 439ed27c81

I've been looking at these emulators too.. Would make an excellent 'B' or replacement A drive.

I have tried a different version of one of these 3.5" 1.44MB USB SSD FLOPPY DRIVE EMULATOR's.
It works fine on IBM compatible machines, but the Atari STFM (TOS 1.2) that I tried it on just ignores it.

Edit: 28th May 2012 - more information on using the Gotek 3.5" 1.44MB USB SSD Floppy Drive Emulator is here

[ralcool]

I will take a SWAG here. (Stupid Wild A$$ Guess)

I'm betting the reason it MAY not have worked. Is the Ataris drive is wired to DS0 (Drive Select)

Given 99.99999% of PC drives are wired to DS1, I reckon these default there too. Unless there is a jumper...then;

The 'cable mod' to the Atari floppy cable where we connect pin 10 (DS0) from the motherboard, to pin 12 (DS1)of the floppy (Which enables hardwired DS1 PC drives to work) Would also apply here.

Then the ST would 'see' it.

[wongck]

Just short pin DS0 & DS1 together on the drive with a solder bridge.
I think it's pin 10 & 12, please check first before doing.

[ralcool]

Its DEFINATELY 10 & 12

Another way would be to insert a fine piece of wire into the ST floppy cable connector, bridging 10&12- since the ST has NO connection to pin 12. Saves hacking an expensive FDD emulator.

Personally I'd mod the cable, but some may find this damaging to the STs authenticity.....

{We won't even talk about how the ST has its FDD motor select lines swapped around, yet it works as DS0....}

I'am Seriously considering buying one of these emulators. And relegating the real floppy to 'B' drive. (100 floppies at the press of a button... HELL YEAH!)
Boot Discs, Games, Demos........et all...!

[wongck]

And also considering there's a thread that is talking about Sony exiting the floppy business....
the SD solution will hopefully persist longer.

[ralcool]

True that... I wonder how long before SD becomes obselete... given the lifespan of PC hardware......


Tonight I modified the TOS 1.4 ROMS (Based on some instructions from elsewhere..) to enable 6ms steprate for all drives.
(A thankyou to Kym for the ultimate answer/result)

Now I can directly boot 1.44Mb floppies without loading a driver, or TOS 2.06. (Which works OK too, except no 1.44Mb format option in the menu unless the driver is used)
But doesn't need it for general operation, and its not there in TOS1.4 eitherway! [Which is why there is a custom formatter supplied as an ACC program]

Only one rom out of six (TOS 1.4 roms) to rewrite (Lo-0), and the result is good. (Only one byte to alter)

Great stuff!

[snoopy]

Here's an article on the different floppy disk drive emulation devices:
http://jimwarholic.com/2009/04/fdd-flop ... lators.php
They are just quite expensive.Just like this ebay auction : http://cgi.ebay.de/Floppy-Emulator-SD-U ... 2306a2fd16

[wongck]

they are mostly meant for production machines.... means that companies that looks at USD$300 as nothing so long as their machine works.

[ralcool]

The MUCH cheaper one I linked to has disappeared (Was only $A60/ 36GBP) ... someone must have bought it...

Have emailed seller.

But booting from 1.44Mb floppies has made life simpler. Have a mean boot disk now.. NVDI etc.... Until HDD mod complete.

[ralcool]

The 68pin PLCC 'plug' adapter arrived.. nice bit of kit. (And ordered well after the pcbs...!) Mearly a plug fitting with 0.050" header pins around sides.

Header pins can be simply removed... And put into the outer row of 'holes' of the Atari plcc socket- much like many older adapters of the past. (Becroft style)

So.. Time to get cracking on a neater Blitter chip mount IDE/ROM/FPU mod. (And the FPU has a messy 3 chip decode circuit to fit...unless a GAL version can be setup)

The new 'blank' precoated PCBs should be here anytime soon, so I'll still make the ROM mount since the design is complete and masks printed. Blame the Airlines.

But using the blitter socket means few wires to attach elsewhere in the ST. Like maybe two. ASCI IRQ and ROM2.

Not to mention building the 72pin simm pcb... my shifter mounted ram has died it seems, so I have routed CAS0/RAS0 lines to the functional 30pin 2x1Mb simms for now.
And working perfectly. Will be a shame to remove them. (But the chosen new 72pin simm is either 8Mb of 60ns FastPage, or 4Mb of 70ns - what a shame we don't know how to make a memory controller for over 4Mb)

Life goes on.

[wongck]

what a shame we don't know how to make a memory controller for over 4Mb
Life goes on.

You may have seen this http://atari4ever.free.fr/hardware/zip/16mbram.zip
I make no sense of it but I am a novice at electronics; may be it make some to you.

[ralcool]

Yes I have seen that document.. I have tried every ST graphic program in my box, and CANNOT load/view those pcx files.

Maybe someone can convert them to gif/jpg.

Besides that, I did read that it was incomplete...what ever that means.

There have been a few kits over the years for over 4Mb, but none ever seems to make DIY status.

Again... Quite a shame. Because I have otherwise no idea how.

[ralcool]

After about an hour of cross checking ST and Mega ST schematics (Which are obviously hand drawn and a little fuzzy- hence cross checking)

I have made a pinout for the Blitter chip. (Since Googling for a datasheet is getting no result)

[1024MAK]

I will take a SWAG here. (Stupid Wild A$$ Guess)

I'm betting the reason it MAY not have worked. Is the Ataris drive is wired to DS0 (Drive Select)

Given 99.99999% of PC drives are wired to DS1, I reckon these default there too. Unless there is a jumper...then;

The 'cable mod' to the Atari floppy cable where we connect pin 10 (DS0) from the motherboard, to pin 12 (DS1)of the floppy (Which enables hardwired DS1 PC drives to work) Would also apply here.

Then the ST would 'see' it.

I am well aware of the non-standard IBM floppy standard, which now has become "the standard".
The version I have does indeed have a jumper to select DS0 or DS1. I forget which position the jumper was set for when I got it, but I selected DS0 for testing on my Atari.
Indeed you can set it up for one of the following:
"S0" (DS0 - cable pin 10),
"S1" (DS1 - cable pin 12),
"S2" (DS0 - cable pin 14),
or even "MOT" (cable pin 16)

Maybe I will investigate further, but I have ordered a "SD CARD Floppy Emulator" which I am waiting for.
These are said to work with a number of machines including Atari ST's.
The listing has ended (Item number: 180489242672)

SD CARD Floppy Emulator.jpg

Once he has processed the current batch he may do some more. See http://atari.plof.pl

[Shredder11]

I'm not sure if you know about this German site, which is excellent and also hosts the best non-corrupted TOS versions along with a lot of user manuals, schematics etc.

http://uk.babelfish.yahoo.com/translate ... =Translate

[1024MAK]

After about an hour of cross checking ST and Mega ST schematics (Which are obviously hand drawn and a little fuzzy- hence cross checking)

I have made a pinout for the Blitter chip. (Since Googling for a datasheet is getting no result)

So are the pins marked " * " unknown or unconnected?

You may also want to "bell out", as in electrical test to ensure that the socket pins are indeed the functions shown in the diagrams as some of these diagrams have errors. I was looking at diagram (not for an Atari, but for another vintage computer) of a serial level chip the other day and wondering where the circuit was for pin 14. Then I spotted that there was two pin 10's!

Keep up the good work

[ralcool]

I should have clarified.

' * ' means ... well both. Looking at my dead ST mother board here.Those pins go nowhere.. no traces connected. (Atari boards seem to be only double sided)

As for whether they do anything in the chip... don't know. But they're not grounded in the ST or held high.. just open circuit socket pads. I would say they are NC (No connect)

Using both ST and Mega diagrams helped cure the difficult to read lettering in the schematic. And all the used pins have traces on the motherboard.

And at least the pin numbering & usage on both diagrams matched.

[ralcool]

Something worth considering.
the Floppy cable 'Standard' Says Motor on for MO0 should be pin 10, MO1 should be 16.

We also know atari use Pin 10 for their drives (The schematics reflect this, and call it D0 SEL -fed from the sound chip) , according to the Floppy Standard, this is Motor Enable Drive 0
We know if we short this to Pin 12 the drives work. Pin 12 is actually DS1.. again according to the standard. {DS0 is actually pin14}

Atari ALSO uses Pin 16 for the Motor on signal. They call it MON.. The FDD standard says this is Motor Enable 1. (Fed from the 1772 via the 7406 buffer)

So our genenal 10-12 shorting hack gets most PC drives back to the usual DS1/MO1 standard. (Some people {correctly} actually cut and route cable pin 10 to 12, removing the MO-0 signal from the drive MO-0 input)

.... if you read THIS you can see for yourself- then compare it to the Normal ST schematics.

http://www.interfacebus.com/PC_Floppy_Drive_PinOut.html
& to confirm.
http://pinouts.ru/Storage/InternalDisk_pinout.shtml


http://dev-docs.atariforge.org/files/Me ... 9-1987.pdf
http://dev-docs.atariforge.org/files/10 ... 6-1987.pdf

So aparently Atari hasn't even been using Drive select correctly on the internal drive at all! Those pin are correctly 12 & 14 which the data sheet show as No Connect.

Bl**dy hell, no wonder some things just don't work. Maybe some floppies can use Motor On instead of Drive select....

YET, the external port does seem better. It has its Motor Select Shared with the internal Drive Pin 16. And then has another TWO pins used for either DS0/1on the motherboard- but only if you set the internal jumper for it- otherwise both pins are DS1.

And we know both the internal and external drive motors come on at the same time. (Some say for increase access speed..ok fine) We can see how their motors are wired together in the diagrams.

But using Motor 0 to actually enable the internal drive in addition to Motor 1 is VERY wierd. No correct use of Drive select as far as the poor old Floppy drive is concerned.Atari diagrams show NO use of pins 12 &14.

Don't believe me... see for yourself. (This is how twisted FDD cables work. The twist swaps 10-16 (MO0-MO1), and 12-14 (DS0-DS1).

We won't even talk about how the STE is wired... its similar, but also strange.

[ralcool]

Reading some of the post around here... its happy days for Atari fans.

WE have The Hydra for Ethernet.. neat little device.
UltraSatan SD HDD. .... elegant use of cheap large SD media
Hxd Floppy emulator.... which can load ST/MSA files, also using SD media.
Eiffel PS2 keyboard and mouse adapter.

and some discontinued stuff like IDE adapters, but still available for DIY enthusiasts.

We really need;

Simbos promised (but not seen) video shifter replacement for all 3 display modes on VGA LCD monitors. Or a internal scan doubler.

A re-release of an overscan device... like LASCAN for example. (I'll finish mine any day soon... c'mon pcbs... got the chips and header pins) with credit to the creator.

Perhaps a re-release of HD floppy kits- Petaris Auto step mod is brilliant. Or similar.

A video shifter mounter 72pin simm memory upgrade or even 4x 1Mb type. (Again mine will be finished soon) I could sell a few. Soldering is unfortunately required without a mmu 'adapter' like old days.

Overclocking is nice, but I can't see anything like a PAK 030 or SST being released again. The 16Mhz hack is limited really, but maybe useful.

A simple TOS 2.06 upgrade. But again doing one without soldering is VERY difficult. (A 'blitter' mounted type similar to my T_Board64 would be solderless- but what old STs have THAT socket!)

History has killed;

ET4000 video boards were limited even in the beginning and had major incompatibility problems. Even ISA bus slot additions can only achieve little useful results. But there is a German site.....

PC emulators (Like my AT-Speed C16-286 , and even better At-Once 386sx) are totally obselete/unavailable- but still useful. (My AT-Speed runs- well ran Windows 3.1- When my HDD is running I'll try again)

TT_Ram upgrades for 14Mb.

Second MFP 68901, for additional serial ports.(And the DIY documents are difficult to understand, and drivers limited)