4 X Floppy Drive Support on Internal Connector?

[Hodgkinson]

Hmmm. I did a bit of research into this, particularly with regards to using 4 PC floppy drives on a A1200. I seem to remember that only DS0 and DS1 are present on the internal connector, and that the external connector has similarly a reduced number of lines.
I believe you need to connect to a IC on the motherboard to get the full DS0 to DS3 in a *decent manner*

As for using PC drives, I gave up after coming to the conclusion that having any less than 4 drives, due to certain required pull-up resistors due to OC outputs on the drives, could result in unpredictable behaviour.

Hodgkinson.

[Hodgkinson]

There’s a guide for using a PC floppy drive on an A500 here, if it’s of any use to anyone:
http://www.ianstedman.co.uk/Downloads/downloads.html

The bit that worries me is that in the ablve diagrams with the PC drive, some of the Amiga input rails are active high, there' normally held low by the O/C PC floppy drive outputs, and there’s a pull-up resistor to that line in the circuit, thus meaning that when no drive was present, the line would be active high.
On the other hand, when using an Amiga drive, the line would be inactive low when the drive isn't present as the high signal coming from the floppy drive signal rail is no longer present.
(NB. This argument would seem to apply to any drive that might not be present out of DF0 to DF3, regardless of the presence of other drives, through the action of the drive select lines).

At least I think this is the reasoning that I came to; it’s a while since I thought about the problem. Due to this, I decided to shelf the multi-PC floppy controller project I was working on (Don’t like the idea of *odd* rail levels confusing the system) and stick to the directly compatible (Just the 1 internal drive on the A1200, as yet) Amiga drive.

Hope someone can follow the reasoning behind this possible *problem*,
Hodgkinson.

[Hodgkinson]

Huh? What jumper (Re A1200)?

EDIT: Two internal floppies shouldn't be too much of a problem, the issues start when you want to use PC floppy drives and have DF2 or 3 internal as well (This needs lines picked from some of the IC's).

Apart from that, mounting them is a issue!

Hodgkinson.