Re: FB-354 drive incompatibility

From: Konrad B <>
Date: Wed, 20 Apr 2016 13:55:38 +0200
Message-ID: <>
"*Andy Finkel explains why the Amiga floppy disk drive has an annoying
clicking sound:*

The story actually is as follows:

When the A1000 came out, we wanted to be able to automatically detect disk
insertion. So Neil Katin came up with the bright idea which solves the
usual problem of disk detection by stepping the drive head, which resets
the disk inserted latch. This, allows us to automatically detect the
insertion of a disk, or the removal of a disk, because the latch is reset."


2016-04-20 13:10 GMT+02:00 Michał Pleban <>:

> Hello!
> I discovered an incompatibility between the FB-354B drive from A500
> which I am using and FB-354C in the C65. The FB-354C has an additional
> signal /DSKIN which tells the computer that the disk is inserted in the
> drive. The FB-354B is missing such signal. It only has /CHNG signal,
> which is supposed to be set when a disk is changed in the drive,
> whatever that means. Actually I cannot figure out what this signal does,
> because when I insert the disk, it always stays on whether I remove the
> disk, reinsert it and so on. I don't see any way to clear it.
> Right now I just hardwired /DSKIN to 0 which means the computer always
> thinks there is a disk in the drive. This has an undesired side effect
> that when there is no disk, any disk operation will hang because the
> computer tries to spin the drive and waits for the index pulse, but the
> drive refuses to spin because there is really no disk, so the index
> pulse never arrives.
> Obviously the FB-354B drive knows whether there is disk inserted or not,
> but does not expose this information outside. Is there any way the "disk
> inserted" signal could be simulated somehow based on the existing
> interface?
> Regards,
> Michau.
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Received on 2016-04-20 12:00:57

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