The Sinclair QL Forum

The idea was to get greater density of databits on the media - I don't think there was any consideration of compatability - I'm not even sure if the heads in the floppy drive might not have both types of coil set...

V1772 is pin compatible and fully the same as WD1772 I don't think the card will work with other disk controllers - there would be both hardware and software changes required. If either the 175 or the 1772 were faulty - this would not likely stop the boot banner from appearing. The first chip is onl...

From memory 2.88 floppies are more unreliable than microdrives and usually wouldn't read on a different drive which is why they are rare and didn't take off. Why bother with floppies when there is the SD plug in floppy emulator that connects to a floppy port? Any 1.44MB disks I ever wrote with the ...

From memory 2.88 floppies are more unreliable than microdrives and usually wouldn't read on a different drive which is why they are rare and didn't take off. Why bother with floppies when there is the SD plug in floppy emulator that connects to a floppy port? Any 1.44MB disks I ever wrote with the ...

Mouser still sell a floppy controller that supports 2.88MB (3.2MB on the QL) drives:

https://www.mouser.com/datasheet/2/268/37c78-468028.pdf

I believe any interface that uses the later specification (IBM PS/2) disk controller can talk to the ED or 4MB floppy drives - they are 4Mb unformatted, but only with their specific media for that. You can find some good info on these drives and the controllers here: https://www.retrotechnology.com/...

o12 is your DSMCL line - DataStrobeMasterChip - it will disable internal devices that would otherwise be selected by the partial address decoding in the standard QL. The equation is built from several lines - each of which is atually the selection of I/O devices, RAM or ROM on the trump card. See if...

you don't need the whole line that activates ROMCS that has /f13 in it - that includes the + (OR) at the start - just use only the first line e,g, /o19 = /i2 * /i1 * /i3 * /i4 * i5 * /i6 + i2 * /i1 * i3 * /i4 * /i5 * /i6 * /f13 (this) o19.oe = vcc becomes /o19 = /i2 * /i1 * /i3 * /i4 * i5 * /i6 o19....

There were different versions of the Trump Card ROM - I think there are a few here: http://www.dilwyn.me.uk/qlrom/index.html

I've seen and used 137 and 218 personally.

The trump card used to do some clever address shifting by moving some of the chip selects around in memory to allow it to place memory where expansions ROM's are normally found. Since you are using Minerva - this scans the various places ROM's can be found in any case, so you only need to decode the...