hey B M O W ! :-) Apple IIgs support - Floppy Emu?

The floppy emu should work fine as the IIgs uses the same IWM floppy controller as the Macintosh Plus and SE. He just needs to add support for mounting 2IMG format images, the standard used by Apple II emulators for 800k 3.5" disks.

http://apple2.org.za/gswv/a2zine/Docs/DiskImage_2MG_Info.txt

Recent implementations to follow for accessing 2IMG files

Ciderpress: http://sourceforge.net/projects/ciderpress/

Apple Commander: http://sourceforge.net/projects/applecommander/

Somebody with a IIgs just needs to try it out!

If it doesn't already work, I think it could be done. Aside from the image file format, the other place where things might need adjustment is in the headers, footers, and checksums for each sector. I know the the IIgs uses the same method to read and write bits from the floppy, but it may still use a different header signature than the Mac, or have a different sector size, or a different checksum algorithm, or something like that. That stuff isn't part of the disk image file - it's generated on the fly by the Floppy Emu firmware.

A cable from the rear to the front is a handy accessory. You can buy one here: http://www.iec-usa.com/cgi-bin/iec/L1561

does that mean that maybe it could also work with the

IIc or IIe as well?

www.apple-iigs.info/doc/dociigs.htm

Buried in there is the Apple IIgs firmware and technical references. They are also on archive.org. The sector sizes should be the same.

does that mean that maybe it could also work with the IIc or IIe as well?

Click to expand...

The Apple IIc, if it has ROM 0 or later, definitely will not work. It uses the SmartPort interface instead of directly accessing the drive since its too slow. Normally the Unidisk 3.5" is used on the IIc and with most IIe interface cards since it has an onboard CPU to handle all the decoding/encoding of data.

UNIDISK is now been sold:

http://tulip-house.ddo.jp/DIGITAL/UNISDISK/english.html

This is mostly for the slot-less Apple IIc, but it will work (slowly) on a IIgs: http://pcedric3.free.fr/SmartportVHD/

The Smartport interface is no barn burner in terms of performance. I have the Unidisk 3.5" to compare with the "dumb" Apple 3.5" drive and having the IWM directly control the drive is a heck of a lot faster. The fastest 3.5" controller by Apple had to have been the FDHD controller. It was more powerful than an Apple IIe! It reads disks about the same speeds as a modern Macintosh.

It doesn't appear that the unisdisk supports 3.5" emulation yet.

Has anyone bought one yet?

http://tulip-house.ddo.jp/DIGITAL/UNISDISK/english.html

I can't get the floppy EMU to load up IIgs images

I made the IIgs images with disk copy 4.2

maybe that is the issue?

The floppy emu accepts DSK files and IMG files….

I do not know how to make a DSK file. How ever it must be more complicated then Disk Copy.

It just sits there Track 00 Side 0 Idle

i even connected the emu to the back of the 800k IIgs floppy drive… booted GOS, and does the same thing.

I can't get the floppy EMU to load up IIgs images
I made the IIgs images with disk copy 4.2

maybe that is the issue?

The floppy emu accepts DSK files and IMG files….

I do not know how to make a DSK file. How ever it must be more complicated then Disk Copy.

It just sits there Track 00 Side 0 Idle

i even connected the emu to the back of the 800k IIgs floppy drive… booted GOS, and does the same thing.

Click to expand...

There's discussion about it at http://www.applefritter.com/node/9479 if that would help you sir?

I think I found the problem. Apple defines pin #4 as chassis ground on Macs, but on an Apple IIgs it is defined for "3.5/5.25 Drive Select". Pin #9 is N/C on a Macintosh (some models provide power on this pin), while the IIgs defines it as "Drive 2 select". On the emulator schematics, pin 4 is grounded and pin 9 isn't connected to anything.

I have a feeling that this problem is related to why the 800k Macintosh 3.5" drive (M0131, the one without an eject button) doesn't work on a IIgs, but the 800k Apple 3.5" Drive (A9M0106 with eject button) does. I don't see any info in Apple IIgs docs on how Pin 4 is used to identify drive type. Pin 9 isn't used on Macs because they only support 2 total 3.5" drives in a given system.

Here is a summery of pin assignments from Apple regarding the IIgs are various Macintosh Models.

Apple IIgs: https://archive.org/stream/Apple_IIgs_Hardware_Reference#page/n87/mode/2up

Macintosh Plus and SE: https://archive.org/stream/apple-guide-macintosh-family-hardware/Apple_Guide_to_the_Macintosh_Family_Hardware_2e#page/n375/mode/2up

FDHD Equipped models: https://archive.org/stream/apple-guide-macintosh-family-hardware/Apple_Guide_to_the_Macintosh_Family_Hardware_2e#page/n387/mode/2up

Some additional info on other Apple II models: http://mirrors.apple2.org.za/ground.icaen.uiowa.edu/MiscInfo/Drives/pinouts.drives

Interesting. I see several other differences in the floppy connector pin assignments between the IIgs and Mac. How are these ever able to use the same external drive?

4: IIgs is 3.5/5.25 Drive Select, Mac is GND

9: IIgs is Drive 2 Select, Mac is N.C.

10: IIgs is Write Protect, Mac is PWM

16: IIgs is Head Select, Mac is register select

17: IIgs is Drive 1 Select, Mac is external drive enable (is drive 1 external?)

Pin 10 is especially troubling, because it's an output on the Mac, and an input on the IIgs, and I don't see any way to reconcile those.

The others could work if Apple chose the right defaults. If GND = 3.5 inch drive, the external drive is drive 1, and head select can be re-mapped to register select in software.

Given that there are some real-world Apple floppy drives that will work on a Mac and a IIgs, this has to be possible somehow.

Here's some more info on Apple IIgs floppy cables that may be relevant: http://apple2.info/wiki/index.php?title=Pinouts#3.5_in._and_5.25_in._Drive_cable_pinouts

PWM is only needed by 400k drives from what I read. The IIgs doesn't support them at all. Pin 10 may not be used by the IIgs despite having an assignment, I have used the A9M0106 800k drive on early 400k Macs without a problem despite the PWM signal being present. Its also possible that the write protect pin is used by the "smart" Unidisk 3.5" drive which can't be used on a Macintosh at all without risking stuff blowing up!

As for Drive 2 Select, the IIgs supports daisy chaining two 3.5" drives on its floppy port, something Macs can't do (there is no internal drive on the IIgs). The pass through board in the Apple 3.5" Disk (A9M0106) likely controls pin 9. It might not be required for the floppy emulator to work, but it might restrict the floppy port to just one drive.

Basically when the machine wants to access drive #2, it activates pin 9 instead of pin 17.

I still think the problem is with pin 4. Since the IIgs floppy port supports both drive types, it needs to be able to determine which type its talking to. The Apple IIgs Setup guide specifically states that all 5.25" drives must be connected after 3.5" drives on the chain. Its likely this pin is left floating on 3.5" drives, but I'll try and dig up more info on how it works. Uniserver could be daring and disconnect pin 4 from ground and see if it works.....

I know you were looking for this earlier, here is some protocol information regarding the IIgs and 3.5" disks: https://archive.org/stream/Apple_IIgs_Firmware_Reference#page/n133/mode/2up

Corrections: https://archive.org/stream/IIgs_2523025_Firmware_Reference#page/n3/mode/2up

Raw disk access info: http://wiretap.area.com/Gopher/Library/Techdoc/Hardware/iwmiigs.txt

And finally, information on what pin-4 does on the IIgs floppy port: https://groups.google.com/d/msg/comp.sys.apple2/WH3jr4M97AM/S5a1XIBgKz8J

Another reference to the 3.5" enable pin: https://groups.google.com/d/msg/comp.sys.apple2/VFZJeum2Cy8/NTqWfXrsCvkJ

i bet if we can make it work with IIgs, NJRoadfan will buy one haha

I'm not sure I understand those docs about pin 4. So is it an input or an output for the IIgs? You're thinking that it should be left floating, rather than connected to GND on the Floppy Emu board? Or should it be driven high (to 5V)?

As a test, you could try physically cutting off pin 4 from Floppy Emu's DB-19, or use a cable and cut the pin 4 wire. It shouldn't affect the behavior when used on a Mac, since there are three other ground lines already.

Perhaps...

Anyway, that 3.5DISK line and the head select line are not controlled by the IWM, but by the VGC (graphics chip). (See page 3 and 4)

www.classiccmp.org/cini/pdf/Apple/Apple ... ematic.pdf‎

Gotta love it when unrelated functions migrate into a chip. Anyway, looking at the hardware reference, the disk interface register (page 153) sets the status of those two pins on the connectors. 3.5DISK pin 4 is "1" (pulled high?) when using 3.5" disks, and Head Select pin 16 selects which head of the drive to use.

https://archive.org/stream/Apple_IIgs_Hardware_Reference_HiRes#page/n175/mode/2up

I'm assuming that when a 3.5" drive is in use, the IIgs software uses pin 16 as a register select (like the Mac), not a direct head select. One of the drive registers is the head select, so the Mac doesn't need a separate pin for it.

OK, so pin 4 on the IIgs is an output, with an in-line series resistor according to the doc. And when the IIgs wants to enable a 3.5 drive, it sets pin 4 high, as well as setting either pin 17 or pin 9 low depending on whether it wants the first or second 3.5 drive. Does that sound right?

If that's the case, then because Floppy Emu ignores line 4, it's going to respond whenever the IIgs sets pin 17 low for either a 3.5 or a 5.25 drive. So it may be getting confused if it checks to see if there's a 5.25 drive connect and then Floppy Emu responds. Or maybe it tries to set pin 4 high, then checks the actual voltage on pin 4 (after the series resistor) to see if it's high or low, and if it's low it assumes there's a 5.25 drive rather than a 3.5 inch drive.

As I think about it more, something doesn't quite add up here:

On a IIgs, a 3.5 drive must only respond when pin 4 is high.

On a Mac, pin 4 will always be low (GND). So a 3.5 drive designed for the IIgs will never respond.

But we know there are some floppy drives that work on both the IIgs and the Mac. How can that be? There doesn't seem to be any way the drive could know what kind of computer it's connected to.

Edit: Maybe the drive could internally have a pull-down resistor on pin 9. On the Mac that's a no-connect, so it would always be low. But on a IIgs it would normally be driven high. Then the drive could be designed to respond if pin 4 is high, pin 9 is high, and pin 17 is low (IIgs mode), or if pin 4 is low, pin 9 is low (thanks to the pull-down), and pin 17 is low (Mac mode). That seems pretty wacky, though.

let me know if and what you want me to test on the IIgs, also will disk copy 4.2 be able to make a proper IIgs floppy image? or should i use, DiskDup+

I haven't found any documents clarifying the drive select pins role with 3.5" drives. I have to disassemble a drive and see how the pins are routed on the daisy chain board.

Looking at the Mac Plus schematics, it looks like pin 16 is head select and its controlled by the 6522 VIA. Besides the change in what chip is controlling it, it should use the same logic across both machines.

On Macs, the Drive Select 1 signal from the IWM is wired to the internal floppy header and Drive Select 2 is wired to pin 17 of the external floppy connector. On the IIgs, Drive Select 1 signal from the IWM is wired to pin 17 and Drive Select 2 is wired to pin 9.

I highly suspect that the 3.5 Disk Enable pin has logic on the floppy drive end. If the pin goes high, the Apple 3.5" drive responds to the machine, if its low it ignores it since the instructions are bound for 5.25" drives. What makes matters confusing is how does the Apple 3.5" drive work on a Mac if this pin is grounded and unused?

the only thing i have to offer is that i did notice when using the Apple® 800k floppy drive with the Macintosh 128k.

it works. @ as 400k drive.

but if i install that same 800k floppy drive internally i have to make sure to use a special cable that has pin 9 and pin 20 cut.. then the drive works. or else it will try to burn out the eject motor.

So the bridge board in the Apple® 3.5 800k external must also disable pin 9 and 20 as well. I don't know if that helps anything… lol

I haven't found any documents clarifying the drive select pins role with 3.5" drives. I have to disassemble a drive and see how the pins are routed on the daisy chain board.

Click to expand...

That would be interesting to see.

Looking at the Mac Plus schematics, it looks like pin 16 is head select and its controlled by the 6522 VIA. Besides the change in what chip is controlling it, it should use the same logic across both machines.

Click to expand...

It's labeled HDSEL on some diagrams, but on the Mac it's just a generic output pin (input to the floppy drive), used in combination with the other pins to read/write one of the 16 internal drive registers. That's the part that Floppy Emu needs the CPLD for.

If the pin goes high, the Apple 3.5" drive responds to the machine, if its low it ignores it since the instructions are bound for 5.25" drives. What makes matters confusing is how does the Apple 3.5" drive work on a Mac if this pin is grounded and unused?

Click to expand...

Exactly. My proposed pulldown solution would work, I think, but it feels too weird to be the right solution.

let me know if and what you want me to test on the IIgs

Click to expand...

I tried hacking pin 4 off one of my Floppy Emus, but the spacing is too tight and I couldn't find any good way to do it without damaging stuff. If you have one of those extension cables from IEC, you could try cutting the wire for pin 4, and see how that affects Floppy Emu with the IIgs.

The daisy chain board is the key and likely controls the drive select logic. I don't want to be responsible for any damage, but its likely the floppy emulator will work on a IIgs, if you connect its internal header to a Apple 3.5" drive's daisy chain board. Using a multimeter, the 3.5 Select and Drive Select lines don't seem to be directly passed through the board. Pin 4 is not wired to chassis ground either.

ok i am going to test this.

Just a thought in my head on possible daisy chain board logic.

At the IIgs disk port:

If pin 4 is grounded on the port, first drive is 5.25" thus no 3.5" drives detected

If pin 4 is not grounded on the port and there is a ground present on some random pin, first drive is 3.5", probe to see if there are two drives

3.5" drive in the chain:

If pin 4 is grounded on daisy chain port, drive is 5.25", route drive select 1 signal to pin 17, only activate if input pin 4 is low from computer.

If pin 4 is not grounded on daisy chain port and there is a ground present on some random pin, drive is 2nd 3.5", route drive select 2 signal from pin 9 to pin 17 (this is how the drive avoids receiving the damaging PWM signal on a compact Mac, it never makes it to the floppy drive to begin with!)

If pin 4 is not grounded and there is no ground present on some random pin, drive is last in chain

This configuration only supports 2x3.5" drives per IIgs, since there is no drive select signal available on pin 9 to the second drive on the chain.

5.25" drives are dumb, they just pass input pin 9 to daisy chain port pin 17. Detecting one or two 3.5" drives connected is likely done by the IIgs firmware. 5.25" don't have auto detection due to their legacy nature.

merry christmas and happy new year.

the first one i loaded, don't know what it was, but it booted and then stalled @ track 33.





so i thought great! oh well !!!! its working!

so then i selected install.dsk witch looks to be gos 6.01 install disk

it works and boots up… my IIgs is acting up… there are some bad caps on the main board that i need to tend to at one point..

but the thing works!! using the 800k bridge board.

Is the machine randomly crashing? Usually dumps to the "*" monitor prompt. Capacitors usually aren't a problem in these, but its possible after 25 years of service. Check the power supply too, they get dodgy with age.

Anyway, that confirms the daisy chain board in the Apple 3.5" drive is what handles the drive select logic.

there are visually bad caps on the board they are leaking

i have another Iigs in the garage with 2.25 megs ram. but too lazy to go get it.

what happens is if i click on any of the control panel items more then once it seems i hear the IIgs reboot beep… and the screen gui just locks, i think i can still move the mouse but i can't remember.. it was late and i was super tired. -- glad it works though… so i would assume this means we need to disconnect pin 4 on the floppy emu?

Yeah, its crashing to monitor, you'll see it briefly when you do the 3 finger salute. I would try disconnecting pin 4 and seeing if it works without the daisy chain board.

Wait, what? It works? That's awesome!

what happens is if i click on any of the control panel items more then once it seems i hear the IIgs reboot beep… and the screen gui just locks

Click to expand...

It's possible that's due to a problem with the floppy emulation not being totally IIgs-compatible, if clicking on a control panel item causes some disk access. What happens if you run this IIgs with a real floppy disk?

What does the daisy chain board do in a normal IIgs system, and where does it go in the chain?

lol i can try, i don't have much space so i have to take the IIgs off my shelf and it takes up my whole desk.

but yeah it works!!! pretty awesome!

Does the IIgs need an eject button? Sorry for the dumb questions - I've never used or even seen a IIgs. But if it doesn't do disk eject in software like the Mac, then Floppy Emu would need an eject button added to make it play nice with the IIgs, right?

i even connected the emu to the back of the 800k IIgs floppy drive… booted GOS, and does the same thing.

Click to expand...

Now I'm confused. Is the daisy chain board part of the 800k IIgs floppy drive, or is it something different? If it's part of the drive, then why didn't Floppy Emu work when you first tried connecting it to the drive's pass-through port?

maybe because there is the known and the unknown… they know what is connected inside…and make adjustments accordingly on the out side its just a raw pass through?

yeah the apple® 800k 3.5 disk drive has a eject button on it.

not sure if the iigs needs it?

I am like you i know almost nothing about the IIGS

I had it on the shelf for a year and a half and never even turned it on to test it. LOL

i have used more in the last week then the whole time i'v owned it

lastnight with the floppy emu and that Disk one install of gos 6.0.1 was the first time i have physically seen it

yeah i know its bad.

mcdermd said its ok though because i'm a mac dude. not apple II guy

i used disk copy to make a 800k gos 6.0.1 disk

and tried to boot it normal and it said something about cannot boot pro dos…

so looks like the Floppy emu is working better then the normal floppy drive…

I wonder if the eject button will "eject" the mounted disk image if pressed. Does the drive activity light work with the emulator? Both the light and the eject button connect to the daisy chain board. The eject button is software controlled, although unlike a Mac, you can arbitrarily eject a disk while its mounted on the GS/OS desktop. It basically does the equivalent of a "Command-Shift-3" although when connected to a Mac, the eject button doesn't function at all. The button is needed to change disks in ProDOS as some software doesn't software auto eject floppies when requesting another disk be inserted. GS/OS is similar to MacOS and even uses the same dialogs when it wants another disk inserted. The machine has full software eject like the Mac, but you can eject on command by pushing the button if you wish.

Now I'm confused. Is the daisy chain board part of the 800k IIgs floppy drive, or is it something different? If it's part of the drive, then why didn't Floppy Emu work when you first tried connecting it to the drive's pass-through port?

Click to expand...

Inside the drive is a raw Sony DSDD floppy drive, the same as found in period Macs. It is connected to a board that holds the DB-19 pass-through to connect another drive and the cable that goes to the computer. This board also seems to handle the eject button in addition to interpreting the "3.5DISK" signal on pin 4 and the Drive Select Signals. On a Mac, its just dead weight.

Uniserver's crashing problem is likely related to the bad capacitors causing system stability problems. If GS/OS had a problem accessing the disk, it would have crashed well before reaching the installer as the boot process loads quite a few files from disk (a real drive seeks A LOT on boot). It would have also kicked back a system error regarding reading disks with the sliding Apple. Dumping to monitor usually means memory is getting trashed.

Inside the drive is a raw Sony DSDD floppy drive, the same as found in period Macs. It is connected to a board that holds the DB-19 pass-through to connect another drive and the cable that goes to the computer. This board also seems to handle the eject button in addition to interpreting the "3.5DISK" signal on pin 4 and the Drive Select Signals.

Click to expand...

I think I get it. This board has a cable to the IIgs, an IDC-20 connector for the floppy drive, and a DB-19 pass-through so you can optionally daisy-chain a second floppy drive, right? So Floppy Emu didn't work when connected to that DB-19 pass-through, but did work when connected to the IDC-20, replacing the real drive mechanism. Makes sense.

I wonder if the eject button will "eject" the mounted disk image if pressed.

Click to expand...

Given what you've told me, I'd guess it does. I can also add an eject feature to the firmware, that's pretty easy. It might be a little confusing for Mac users to see an "eject" option, though.

So yeah, I'm very interested in what modifications to Floppy Emu would be necessary to make it work on the IIgs without requiring that daisy-chain board. Ideally while still maintaining interoperability with other real 3.5 drives in the chain. Does anyone have a high-res photo of the daisy chain board? Does it have any ICs on it, or is it just a bunch of passive components?

Unfourtunatly this board is far from simple in design. It has a ton of passives, plus a Sony CXD1085B IC. Also the later Apple FDHD external drive (G7287) has a slightly different board that lacks the pass through DB-19. This drive was mostly intended for the Mac, but works with the Apple FDHD controller card for the Apple II as well.

well, ah… chances are pretty good if you have a iigs, you probably have one of these 800k drives yes?

Yes, usually the drive is paired with a IIgs. It is VERY common.

Hmm, it seems kind of lame to say you need a real floppy drive in order to use the floppy emulator. But if virtually every IIgs owner has one already, I guess it would be OK. It still beats keeping a collection of slowly-decaying 3.5 inch floppies in a box somewhere!

lol yeah man

should i try it with pin 4 disabled?

I say give it a shot if you are comfortable with making the change to the board.

ok ill try.

ok so i heated up pin 4 and lifted it. i guess ill try it and see what happens

nope, pin 4 open

doesn't boot.

connected directly

hey i just thought of something

there is this guy that makes a IIgs UNIDISK EMU

and he talks about having to special set of buttons on the EMU in order to enable the unidisk mode

for it to boot…

http://tulip-house.ddo.jp/DIGITAL/UNISDISK/english.html

UNISDISK can be used with any Apple II. With an Apple II / II Plus / IIe with a DISK II interface card, you can only use DISK II mode. With an Apple II GS, you can use both modes. With an Apple IIc, you will only be able to use a drive 2 in DISK II mode. I've not tested the SmartPort mode with a IIc / IIc plus yet.

Click to expand...

Turn on the power of the Apple II while pushing the "down" button on the UNISDISK. This makes the mode of the UNISDISK as "DISK II mode".Select a .DSK/.DO image following the instruction below.

A .NIC file is generated, and the .DSK/.DO image is converted to the .NIC file, and escape UI mode. A NIC file is an actual file the UNISDISK accesses while DISK II operation. Once a .NIC file has been generated for a .DSK file, you don't have to generate it again.

If you use an Apple II GS (and maybe IIc / IIc plus), turn the power off, wait 10 seconds and turn the power on again.

Click to expand...

That unit emulates 5.25" drives. Strange as it may sound, Apple made two slightly different 5.25" drives with DB-19 connectors on them.

-The UniDisk 5.25" Drive (A9M0104)

-The Apple 5.25" Drive (A9M0107)

Both look the same aside from the label on the bottom. The difference is the Unidisk 5.25" requires the -12v power line on the floppy port. This is why this drive won't work with the Apple IIe Card for the LC PDS.

Too bad the pin 4 thing didn't work. I guess there is other logic at play with that daisy chain board. Thing is, most solid state disk needs on the Apple II can be handled by the CFFA3000. The number of programs that require a 3.5" drive because they directly drive the IWM is very small (mostly demoscene stuff). The Apple IIe/c/gs is blessed with a device independent block storage interface in ROM called "SmartPort", which makes emulating storage devices a cinch. Most major emulators take advantage of this feature too.

i guess the next thing to do is figure out what that SONY I/C does on the 800k bridge board…...

I just noticed the schematics for the Unidisk 3.5 drive are online here: http://bitsavers.trailing-edge.com/pdf/apple/disk/sony/Unidisk_Schematic.pdf I didn't really look at it in detail, but it can probably answer a lot of questions.

ok sir i will look at it !

i know you don't want one… i think i am going to send you a IIgs man.

wholy crap. Thats the wholy grail right there. internal schematics of the GLU. Too bad we dont have that for SE/30s or other things.

At least now that its out there, a duplicate can be built.

Reading the blurry text on page 3, its the schematic for the Sony CXD1085. The 2nd page is interesting as it looks like an earlier/simplier design. I'll have to look at the inside of the Unidisk 3.5" I have. Its an older drive, but I don't think you can daisy chain 5.25" drives behind it on the IIgs.

Actually you can daisey-chain a 5.25" drive to a 3.5" Unidisk on the IIgs. Done it a few times.

Though Apple says you shouldn't, I've temporarily had 2 3.5" IIgs drives as well as 4 3.5" Unidisks connected. Was installing system software and hated the floppy shuffle

Reading the blurry text on page 3, its the schematic for the Sony CXD1085. The 2nd page is interesting as it looks like an earlier/simplier design. I'll have to look at the inside of the Unidisk 3.5" I have. Its an older drive, but I don't think you can daisy chain 5.25" drives behind it on the IIgs.

Click to expand...