HxC Floppy Drive Emulator

You can find the VCO schematic there : http://24.dtiblog.com/k/kitahei88/file/ ... ematic.pdf

There are 2 signals coming from the computer : one to select the VCO mode : FM or MFM, and the other to select the bitrate.



mhh in fact this is as you want.



These signals are needed since the computer need to be able to change the VFO mode.

I think I understand this, but my confusion is to what exactly the enclosure is doing -- if I am using the HxC and the VFO circuit with no physical floppy disk drives being used shouldn't these signals be on the floppy data cable, or do you mean it necessary to take into account the signals over this wire that was previously going to the jumpers on the disk drives? The VFO board above does not seem to have any extra pins for this, however if this is simply communicated over the floppy data cable and these floppy drives traditionally had VFO hardware in them why would NEC need to do this with an additional wire? If somebody plugged one of these drives directly into a computer in 1985 how would they get information to that RD pin?

Is perhaps SYNC/WINDOW only possible over the 50 pin external floppy connector, maybe that is what is going on? Is that real SCSI?

Hello,floam.

for PC-98x1 series, external 50 pin has much more signals(like fail unsafe,low write current and so on) for early 8inch drives.
and internal 34 pin has also 'Window','FM/MFM' and 'SYNC'.
#3 is Window , #7 is FM/MFM and #11 is SYNC.

Which PC-98 model do you want exactly to use with HxC and VFO?
In later model than PC-9801VM , we need dataseparetor for FD side.
Or what drive is in your PC-98x1 machine ?
NEC drives show model number like 'FD1157D' .
Last alphabetical letter 'D" model has dataseparator in FD, and 'C" model doesn't have .

I made dataseparator reffering to dataseparator board in old external drives.
I got 4 or 5 dataseparator boards and check with HxC .
some dataseparator worked with HxC instability , and only use 2HD images.
The dataseparator using SED9421C0B chip for VFO is working good and work for 2DD images.
so I made my board to use SED9421C0B.

Do you want my dataseparator board ?
It will take several weeks that I order new PCB board to HK PCB sevices.

It is a FC-9801V.


This machine had two FD1135D units inside of a PC-9831-VW2 enclosure.

So you have been using FC-9801 with PC-9831-VW2 external drive connected by 50 pins straight cable .
and you want HxC for external drives like PC-9831-VW2 now ?

I think probably my dataseparator board and additional board(convert 34pin to 50 pin) worked with FC-9801 for external drives , but I don't have FC-9801 series and I have never use it .

Since a few people want to get dataseparator , I will order PCB tomorrow.
for more detail, I will mail you tomorrow.

That's correct. I was planning to mount the HxC inside that PC-9831-VW2 connected to its internal FDD connector and replace the two floppy drives. But I do not care how I do it, it is only important to me is that I emulate two of these crazy floppy drives with one HxC over one 50-pin cable and have sync/window work. I have seen that other board you have that does the conversion to 50-pin and I would be perfectly willing to use that instead if you think it would be a better idea.

NEC PC-9831-VW2 has two FD1135D ,3.5 inch 2mode ( I mean DD and HD ,360 rpm drive) drives, in it.
And the dataseparator is in each FD1135D drive itself , not PC-9831-VW2 drive unit.
So you cannot use HxC to exchange FD1135D simply .

I think that drive unit board just only work with drive select and HD/DD mode change , not data separation.
FC-9801 series only have 1Mbyte Drive connection , not 640kbyte DD mode.
#some kind of FC-9801 has 320Kbyte drive connection (for 5.25 inch 2D drive )
so I think you may work with drives that can read/write 3.5inch 2HD disk only.

Can you use the PC-9831-VW2 at showing your picture ? ( SW1 is 1/2 , not 3/4 and SW2 is 1MB not 640KB)
It's is so , my dataseparator may help you .

Yes those switches are never changed. Always 1/2 and 1MB disks. Mostly use standard 1.44MB IBM 2HD floppies with it and let the machine format them.

OK , I understand.
I send email to you.
plz check it.
#it may have been a spam mail .

Hey, guys. I have a Japax Japt 3E CNC, about 20 to 30 years old. It works with a casette (TEAC DATA-PACK MT-7,19305010-DD) that used to be written with coordinates(X and Y) that the CNC used for cutting the piece. The casette reader is not working anymore and the coordinates must be input manually. I am trying to find a solution to connect a PC or a micro-controller to the CNC. I am not much into electronics, I am a student but I am willing to learn and collaborate in finding a solution. The casette reader used to be connected to the CNC through a 24 pin slot. I also have found IDE cables that run from the display that shows the coordinates to the mother board I suppose and I assume that a micro-controller may be connected to input coordinates. So, have you guys found anything that could help?

Regarding the JAPAX EDM wire machines - I've done some work for a machinist friend of mine. The System disks are 78 tracks and the data disks are 77 tracks. Head 0 of Track 0 is indeed FM 128 byte sectors and all the other heads and tracks (including track 0 head 1)are MFM 256 byte sectors ( 26 sectors per track ). The disks do run at 360 RPM and all recording is at 500kbs. The interleave on all tracks is 2 - the interleave only affects the speed of successive sector retrieval). There is no track to track skew offset . This is very similar (but not exact) to the old 5.25 floppies or the old Commodore disk drives.

The data disks do not use track 0, but the system disk uses track 0, head 0 and has data. The 78th track on the system disk has data in the first sector and it consists of the string "*JPAX **** (date and time ) ******* (*'s to the end)". The disk is not recognized as a system disk unless this sector is present.

I wrote a C program with user interface that uses Simon Owen's fdraw.sys driver ( thanks Simon for your help) and it can copy a disk to a file, write the file back to a disk, and format a disk. It does this on a regular PC using a tri-mode floppy ( Teac FD-235HG to be exact ) with pin 2 on the interface grounded. The PC must have a fully compatible NEC765 interface because it writes all the gaps and flux changes. Most older PCs with floppy connectors on the motherboard do this. A floppy connected via a USB port does not (as far as I know).

Because the data is written at 500k and a normal IBM floppy has 200 ms of time per track (note the JAPAX disks run at 166ms per track ) it might be possible to interface an ibm disk with all the gaps and formats preset on a disk so that the data stream is identical except for a 33 ms gap between the last sector and the start of first sector. The controller should just be looking for the start sequence so the time of this gap shouldn't matter. We have not tried this, deeming it to be a last resort. Any such arrangement would require that all disks be formatted on a regular PC and not on the machine tool since it would not properly drive the timing on the ibm floppy to do the format.

We have not successfully found a floppy emulator that will allow mixed formatting, or for that matter any arbitrary gap and sector formatting to duplicate the JAPAX track0, head 0 behavior along with the other tracks.

You have just found it : The HxC Floppy Emulator !
Mixed track format / sector / gap are supported by design : the HFE file format store the tracks at the MFM/FM bitstream level.

My advice : Dump your disk with ImageDisk and convert the IMD file to the HFE file format with the HxC Floppy Emulator software.

I have a correction to my previous post about the JAPAX EDM disks. The system diskette has 79 tracks not, 78. The 78th track, track number 77, is not formatted it is totally missing. The 79th track ( track number 78 starting at 0 ) is the one with the JPAX system flag. I tried reading one of the diskettes with the Floppy Dump of the Hxc emulator software and it does not read this properly. It goes through the motion, hiccups on non-formatted track number 77, then reads track number 78 ( the 79th track ). It creates a file with the correct length but the data of the last track is wrong, and it indicates there are 78 tracks not 79. In reality there are 78 and 1/2 tracks because the second side of the last track is also not formatted. I'm guessing it cannot handle the fact that a track is not formatted or maybe only one side formatted. I'll have to run an experiment to see if the EDM machine will work with a disk that has a formatted track number 77 and a formatted side 2 of track number 78, so that all 79 tracks are formatted. The Hxc software does read and export the odd formatting of track number 0.

Here is some more info. If I format both sides of the disk then the Hxc software does read all the data correctly, so there is some problem if only one side of the track is formatted.

Also I notice that even though track 0 head 0 is formatted FM, the Floppy Dump command status window shows it as MFM while it is reading it. Is there some way to verify that the .hfe file really has t0h0 as an FM track and not an MFM track? It does have 128 bytes/sector because it shows in the graph.

Send me the HFE file, i will check it.

You can also use the Track Analyser of the beta version :
http://hxc2001.free.fr/floppy_drive_emu ... 2_beta.zip



And as i said : try to use ImageDisk and send me the IMD file :
http://www.classiccmp.org/dunfield/img54306/imd118.zip