Re: IEEE-488 adapter for 1541

Den Sat, 6 Apr 2019 17:37:27 +0200 skrev Francesco Messineo
<francesco.messineo_at_gmail.com>:
> Hi Jeffrey!
> I also started some years ago my own project for converting a 1451
> into a 2031LP, of course with switchable kernel and maintaining both
> ports. A daughterboard is quite an easy thing to add to the 6522.
> However I realized that 1541 format isn't write-compatible with the
> 3040/4040, so at least for me it wouldn't allow me to share the same
> disk (well, share in read only mode, yes) between my PETs.
> Converting a 1541C is way easier anyway, you don't need a ROM adapter,
> just a 27256 and a switch and you can re-use the 27128 socket on the
> 1541C motherboard.

Isn't the 1541C like a 1541 but with a track 0 sensor and changed ROM
to use that sensor? My impression were that this still used two 8kbyte
ROMs.

IIRC the track 0 sensor interferes with the I/O ports required for the
IEEE-488 port. The linked description probably takes care of this, but
I'd advice to check what parts of the ROM does the track 0 check. If it
isn't in the same ROM as the IEEE/IEC code, then both ROMs needs to be
switched instead of only one of them.

While 1541-II is the new style case drive which indeed uses one 16kbyte
27128.

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