Is it normal drive behaviour?

[khaz]

Hi there

I have two drives connected and whether I access one or the other, both motors spin concurrently. Is it normal?
Also when only the ribbon cable is connected to the CPC (second drive completely disconnected from both the ribbon and power cable), CP/M Still detects two drives.
Disckit3 is also acting weird with two drives. It behaves normally but once the operations are done and it asks to remove discs from both drives, it doesn't detect that the second drive is also empty. It's fine when only one drive is connected.

I've tested it with both an HxC and a 3.5 drive. The cable has only pins 1 and 2 connected.

[pelrun]

The motor signal is shared by all drives, so yes, it's normal.


Everything else is related. Your cable forces the ready signal to be on, which means CP/M, Disckit3, everything is being told that there's a disc present.


Your HxC can generate a proper ready signal, and so can a bunch of 3.5" drives if you modify them. Unless you do that and remove the 1-2 pin connection in the cable, nothing will be able to tell the true status of the second drive.

[khaz]

Now that's interesting. So you are saying I don't need that 1-2 jumper if I used only the HxC? Is there a specific setting to use or is it automatic?

Do you have a lead on how to perform that 3.5 drive mod?

[PulkoMandy]

The HxC is set by default to emulate a standard shugart floppy drive. This is what any computer out there expects, with the notable exception of PC compatible machines.

On the PC, one signal was replaced to avoid having to poll the disk drive to detect disc changes. This makes PC disk drives incompatible with other machines, and on CPC the "easy" fix is to force the signal so the CPC always thinks there is a disc in the drive.

For 3.5" drives, there is usually (but not always, unfortunately) a 0ohm resistor near the connector, which is set on the "DC" position ('disk change') and must be set to "RD" ('ready') instead. The exact markings can vary a bit. The oldest drives even have jumpers to easily change this.

Some info here: Modify PC floppy drives - CPCWiki

[khaz]

My cable has its jumper glued, so I won't be able to experiment until I receive another one.

I don't have one of those easy drives with jumpers, unfortunately. However mine is a Sony MPF920, which seems fairly well documented even though every mod on the web differ slightly from each other. I'll give it a go as soon as I get my new cable though, the Ready signal is something that I really want.
How to modify a Sony MPF 920 to provide a ready signal (cpcwiki forum thread)

Maybe the wiki entry should be updated with this information?
Guide on how to connect a 3.5 - CPCWiki
Guide on how to connect a 3.5" drive to a CPC6128/664 - CPCWiki
Both seem to state that shorting pins 33-34 is essential to a working cable, and as such ebay sellers do it by default.
(also maybe merging these two articles? They are highly redundant.)