Slave drive for Microdisc

If you want to ask questions about how the machine works, peculiar details, the differences between models, here it is !
How to program the oric hardware (VIA, FDC, ...) is also welcome.
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Slave drive for Microdisc

Post by jorodr » Sun Nov 11, 2007 8:14 pm

Hallo :)

Does anybody know is there a way to connect Amstrad drive to Oric as a slave drive?
Or may I use Amstrad drive for this?:
http://www.old-computers.com/magazine/view.asp?r=5&a=12

best regards :)

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Post by mmu_man » Mon Nov 12, 2007 2:37 pm

You just need to build the cable.
All those drives use the Shuggart interface, which is the same as the one on the PC floppies.
The only changes are the pinouts, most external interfaces are repackaging of the shuggart signals into a different connector. some internal drives use non-standard pinouts though (like IBM drives).
The Microdisc slave port is likely also a variation on the shuggart pinout.
See http://www.hardwarebook.info/Category:Diskdrive

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Post by jorodr » Mon Nov 12, 2007 10:25 pm

Is that mean that I can connect usual 3.5'' PC floppy drive as slave to Microdisc?

Thanks :)

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Post by Dbug » Mon Nov 12, 2007 11:10 pm

With the usual restriction about pc HDD drive: They suck.

Most of them are hardcoded to use ID 1, so you have to use a twisted ribbon cable to set it to ID 0 (or you have to use it as a secondary drive), and then after that you have no guarantee it will manage to write double density data.

Now if instead you get a double density drive, like what can be found in Atari ST machines, you have a perfectly working and reliable 720k disk drive :)

For the PC disc, you best bet is to get on in a 8086/286/389/486 machine.
From Pentium time and later the probability it works fine decreases fast.

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Microdisc slave

Post by jorodr » Thu Nov 15, 2007 2:00 pm

I have 3.5'' drive from Amiga 600. Can I use it with regular 34 wires cable? Is there a difference between 3.5'' drive pinouts and Microdisc's slave drive pinouts? If so, where I can find the pinouts for external drive to Microdisc?

Thanks :)
Last edited by jorodr on Thu Nov 15, 2007 2:09 pm, edited 1 time in total.

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Post by waskol » Thu Nov 15, 2007 2:06 pm

hmmm, becarefull, there are a few hardware differences between an Amiga floppy drive and a PC floppy driver. The former are working at variable angular speeds, while the PC drives are working at constant speed (that's why an amiga floppy drive can write 880Kb of data on a floppy and a PC drive only 720Ko).

Thus, I am not sure at all if you can adapt an Amiga drive as a slave for an Oric Microdisc.

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Post by carlsson » Thu Nov 15, 2007 2:16 pm

Since a PC drive with a few cable twists can be used on an Amiga, I don't think it is out of the question to use an Amiga drive for this cause. Basically, it seems the Chinon FB-354 was used as the internal drive both in Amiga 500 and Atari 520ST. I think it is the floppy drive controller that handles all the fancy stuff. Besides, the Amiga reads 80 tracks of one sector each and in software divide those into smaller sectors. I can't remember hearing about it reading at different speeds. The Macintosh however has these tricks going on, and a Mac drive appears incompatible with just about anything else.
Anders Carlsson

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Post by jorodr » Thu Nov 15, 2007 4:00 pm

Qusetion is: can I use regular 34 wires cable from PC to connect amiga drive to Microdisc slave bus. Are pinouts of Microdisc slave and Amiga (Atari) flopy drive identical...I don't want to blow up my golden Microdisc :)))

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Post by mmu_man » Thu Nov 15, 2007 10:10 pm

carlsson wrote:Besides, the Amiga reads 80 tracks of one sector each and in software divide those into smaller sectors. I can't remember hearing about it reading at different speeds. The Macintosh however has these tricks going on, and a Mac drive appears incompatible with just about anything else.
Yes the Amiga just used a different format and file system, but likely uses the same coding as PC, unlike the Mac which uses its own bit coding (GCR instead of MFM).

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Re: JORODR

Post by mmu_man » Thu Nov 15, 2007 10:37 pm

jorodr wrote:Qusetion is: can I use regular 34 wires cable from PC to connect amiga drive to Microdisc slave bus. Are pinouts of Microdisc slave and Amiga (Atari) flopy drive identical...I don't want to blow up my golden Microdisc :)))
It should be, but this needs checking.
Never used one, so...
I'm sure I had the pinout of that connector somewhere but can't find it.
You'll have to make the keying is correct.
If you read french you can find some info there

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Post by jorodr » Thu Nov 15, 2007 10:41 pm

And the switch on Amiga drive must be set ot 1, right? Sorry if I asc questions like an Idiot, but in Bulgaria we never have had Microdisc's.

Thanks mmu_man. This was really useful information. I have a french-speaking man (old Pravetz 8D fan) who will translate :))) If you find the pinouts of the connector, let us know :)
Thanks in advance :)

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Post by mmu_man » Thu Nov 15, 2007 11:08 pm

Hmm found interesting sites...
This one tells how to connect a slave drive to a PC, which is just the opposite:
http://www.old-computers.com/magazine/view.asp?r=5&a=12
Didn't know that site had this page :)

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hi

Post by romualdl » Fri Nov 16, 2007 2:50 pm

Hi,

I wrote this article for old-computers.com when they launched the new version a few years ago. The webmasters were looking for some content (technical and meeting stuff). I also added a 3.5 inch floppy to my microdisk unit (as master drive keeping the 3inch drive as B-drive).



A+
Romu

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Post by jorodr » Fri Nov 16, 2007 3:37 pm

Hey romualdl, thats great :)))

Tell me if I have Atari floppy drive or early PC floppy drive, need I to make changes in cable to connect to Microdisc ? From all I've heard here I thing I will not need, but it's better to hear it from somebody with big experience :)

Thanks in advance :)

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Post by highwayman » Fri Nov 16, 2007 7:46 pm

the difference between amiga drives & pc drives has nothing to do with angle or encoding,

the amiga uses "diskchange" signal to detect a disk and the pc dousnt,
and the other difference is the use of the "index" signal.

some drives have small jumpers to configure these pins - chinon mostly.
i remember all this because i remember trying to get cheap drives to put into amiga's back in the day.

and dont use high-density disks as double-density,
a high density drive can detect the disk type and change it's settings.

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