QL's external MDV port

[tcat]

Hi,

There is an external MDV port on the standard QL. I am led to believe that it suited to ZX Spectrum MDV unit so it can be plugged in as an additional microdrive device, perhaps the whole chain of units, so they may appear as MDV3_ ... MDVn_ accessible to the QDOS.

Question is, can I also connect QL's MDV unit to this port, what the wiring diagram would be, or is some signal converter needed?

My idea is to test some QL microdrive units through this port without need of disassembling QL case.

Many thanks
Tom

[1024MAK]

Not that I have tried myself, but yes, it has been reported by other users that Spectrum microdrives work. There is an annoying snag - they only fit backwards!

If you can make a suitable connector, QL microdrives should work, as the external port is just an extension of the internal microdive "bus".

Mark

[dilwyn]

Although Spectrum micro drives can be connected, they end up facing the wrong way and somewhat annoyingly you can't format a QL cartridge in them. But if you format a cartridge on a QL they can then be read from and written to on a Spectrum microdrive attached to a QL.

Not sure why, maybe speed difference, as QL formats cartridges to slightly higher capacity than Spectrum.

Never heard of anyone connecting QL microdrive in this way - good luck and if you succeed let me have the details to document it on my website.

[Nasta]

You can't directly connect QL microdrives to the port because a part of the necessary circuitry to make an internal unit to an external one is on the QL motherboard. However, one could build that part up on a small board with the appropriate edge connector and use an internal unit as an external one.

[Paul]

You will also need to have both internal microdrives installed. Otherwise driveselect isn't connected to the external bus.

[tcat]

Hi,

As for QL MDVs, I learnt that various Issue version exists, 5,6,7... etc, similarly as the QL main boards.
My QL is Issue6.

I wonder what differences in perfomance, or functionality, I may expect between different MDV Issue#, say If I connected Issue5,6,7,... MDV to my external port of the QL Issue6?

Do the various MDVs' Issues# also differ in ULA specific versions and their kind of serial numbers. Can ULAs also be swapped on MDV, upgraded so to speak?

Many thanks
Tom

[Outsoft]

Just test and It works

Well the Speccy MD can't read a QL MD but...If we format an MD on a QL the Speccy Drive can read it and...write to it!

So It means that a WCOPY MDV1_ to MDV3_ seems works perfectly

Well at the end the MDV SAVE routine fail to check the last file written but...the program copied works perfectly:

https://www.youtube.com/watch?v=Ngm_KgFmFAw

[tcat]

If you can make a suitable connector, QL microdrives should work, as the external port is just an extension of the internal microdive "bus".

Hi, this is what I have to make a connector, original ZX connection piece, and an IC socket, to plug the QL MDV into.
What is needed is a small piece of PCB with connection tracks, and to solder the IC socket onto.

I am not sure about wiring as to where the white wire from the upper strap of QL MDV unit should go?
Please see pictures.

Many thanks
Tom

[Outsoft]

If you can make a suitable connector, QL microdrives should work, as the external port is just an extension of the internal microdive "bus".

Hi, this is what I have to make a connector, original ZX connection piece, and an IC socket, to plug the QL MDV into.
What is needed is a small piece of PCB with connection tracks, and to solder the IC socket onto.

I am not sure about wiring as to where the white wire from the upper strap of QL MDV unit should go?
Please see pictures.

Many thanks
Tom

It will be very interesting to connect a QL MD externally to arrange better is cleaning

Powered by the QL naturally as do with the Speccy MD unit too

[tcat]

Hi,

You can't directly connect QL microdrives to the port because a part of the necessary circuitry is on the QL motherboard

What kind of circuitry is need, I thought the external port is just an extension of the internal microdrive "bus", as advised here by MAK.

Also it is proved ZX MD units can be connected directly, so I believed only an adapter is need.

Many thanks.

Tomas