Floppy Emu update: Mac 128K/512K support

[bigmessowires]

OK, I've got some new firmware that gets Floppy Emu sort-of-working on Macs with the original 64K ROM (the Mac 128K and 512K un-enhanced). With this change, there's no more Sad Mac 0F0004 on boot up, and I was able to successfully boot System 3.3.0 many times on a Mac 512K, and verify that read and write emulation works!

The "sort-of-working" part is that System 3.3.0 appears to be the ONLY disk image that works. I tried two different versions of System 1.1 boot images, and they both die with Sad Mac 0F0062 when the disk is inserted.

It's encouraging that at least System 3.3.0 works - maybe there's just something bad about my 1.1 disk images. Or maybe there's something in the System 1.1 code that's a problem. Bbraun, dougg3, haplain, and anyone else with hardware: if you guys have any other bootable 400K disk images, I'd be curious to see what results you get.

The new firmware is at http://www.bigmessowires.com/floppy-emu-64K.zip It's important to apply both the new CPLD firmware (firmware.xvf) *and* the new AVR application (floppyemu.hex, or femu.bin if you're using the SD bootloader to update the AVR). I've been changing the signal assignments of the traces connecting the two chips, so if you update one without the other, you could leave yourself in a fubar state, or create contention where both chips try to drive the same line.

Also, I think the versions of the 3.3.0 and 1.1 disk images that I originally distributed are wrong. For one thing, they're 800K, and for another, at least one of them appears to be a HFS image instead of MFS. I've included two new disk images in the ZIP file.

 

[dougg3]

Cool! With bbraun's assistance for the fusebit settings (looks like high = 0xBF, low = 0xDA, ext. = 0xFF), I got the new AVR and CPLD firmware flashed.

I don't have a 128K or 512K to play with (only a Plus if needed), so I don't know how useful this info is, but your new Disk011.dsk and Sys330.dsk images definitely mount OK on my IIci through the floppy emu....

 

[bigmessowires]

Cool, sorry I forgot to explain the bootloader. Now that you've got it installed, for future updates you can copy femu.bin to your SD card, and then press Reset while holding PREV and SELECT. The ISP programmer isn't needed.

Good news! After many hours of scouring the web for ancient system software, and converting it to the right disk image format, all the 400K disk images I tried worked great on my Mac 512K:

System 2.0

Bootable MacPaint (system 2.0)

Bootable MacWrite (system 2.0)

System 3.2 HD 20

System 3.2 Installer

The only disk that doesn't work is that Disk011.dsk. I need to try copying that to a real floppy, and booting my 512K with that, to see if it's the disk contents or the Floppy Emu at fault. But at the moment the 512K's floppy drive is out of commission, so I need to get that working before I can try it.

 

[bigmessowires]

I found a System 0.97/Finder 1.0 image that works, as well as a French System 1.1 Finder 1.1, and the 400K version of Dark Castle. All run fine as emulated 400K disks under Floppy Emu on the Mac 512K. I don't know what's up with the US System 1.1/Finder 1.1 image, but I'm not going to worry about it any further.

Looks like Floppy Emu is now officially working on these 64K ROM Macs! Now, for 1.44MB floppy emulation support...

 

[onlyonemac]

Just try redownloading the System 1 disk images from Apple (if they've got them, that is ).

I just remembered that I've also got a System 1 disk image, but on second thought I think it was the one which came in the floppyemu download (I downloaded it when I was trying to make a 1.44 MB version).

Now, for 1.44MB floppy emulation support...

And then I'm gonna nag you for a free one!!! And a schematic of your CPU, since I would like to see how it compares with my own CPU design.

 

[bigmessowires]

More info: there's definitely something screwy about that System 1.1 disk image. The real floppy drive magically started working, so I made a 400K floppy from the System 1.1 image, and tried booting the Mac 512K with that. It crashes with the same 0F0062 Sad Mac error as I get when using Floppy Emu, so it's definitely a problem with the software and not the Floppy Emu. Strange that the same System 1.1 disk image boots up fine in a Mac 512Ke and a Mac Plus. But at least the Floppy Emu seems to be behaving identically to a real floppy drive here.

 

[uniserver]

that is slightly strange, could the fact that the drives are variable speed have something to do with it?

 

[Gorgonops]

that is slightly strange, could the fact that the drives are variable speed have something to do with it?

Note that all Mac floppy drives are variable speed. The difference between the 400K and all the later ones is the speed of the 400K is directly regulated based on a PWM signal from the motherboard, while all the later ones automatically change speed based on what track they're on. (IE, they ignore/don't need the PWM signal.)

 

[uniserver]

Ahh, so could that explain why the 400k sounds different then the 800k? the PWM is controlling 400k?

lol i'm sure this is why he made a separate thread for this topic :-D

viewtopic.php?f=7&t=22231

or maybe its just a differently designed SEEK and Drive motor I know for sure the SEEK motor is different on the 800k drive.

 

[Cory5412]

And then I'm gonna nag you for a free one!!!

This is basically the holy grail of the 68k Mac scene. Be prepared to pay to have one built, or build it yourself.

 

[Bunsen]

I'l just point out here that the two that went up on ebay - without 1.4MB support - cleared over $300 each.

This "freebie me!" joke is wearing thin, onlyonemac.

 

[bigmessowires]

If I can get organized enough to build a bunch more, hopefully I can offer them for a lot less than $300. But probably not free.

 

[techknight]

I dunno, they have to be worth at least $100/$150, maybe even what they sold for! ;-) Considering they are the holy grail of vintage macs, the SCSI/SD/CF runs a close 2nd.

 

[ajacocks]

Yeah, color me really excited about this project. I'll be interested, when they are available, for sure.

- Alex

 

[bigmessowires]

New update: adds support for the Mac Classic (and probably a bunch of others with similar ROM)

http://www.bigmessowires.com/floppy-emu-1.0E-F4.zip

Known compatible Macs:

512K

512Ke

Plus

SE 800K

Classic

I don't know of any *incompatible* Macs, but these are the only ones that have been tested so far.

 

[NJRoadfan]

Would be interesting to try on the Apple IIgs' on-board interface and some of the A2 add-on cards that support 800k drives like the Central Point Universal Disk Controller and Apple FDHD Controller.

 

[bigmessowires]

If those used the same disk format as the Mac, then it should work. I'm fairly certain the drives themselves are compatible, but not sure if the IIgs used the same low-level scheme for marking sectors on the disk, checksumming, D5 AA 96 and all that fun GCR encoding stuff. :beige:

 

[Bunsen]

Will you be sending the new firmware to your two ebay customers?

 

[bigmessowires]

Yup. One of them is right here on the forums, the other never responded to my contact through eBay so I don't know if he/she got it.