Schematic and ROM for floppy interface ?

[Nasta]

WD 2793 chip was used by the Micro Peripherals interface, someone whould have a BIN file to burn a ROM with. The tricky part is the schematic - I reverse-engineered mine a long time ago, and have no idea where all those old QL papers are now... the original software does not support HD even though the chip does, there are unused bits on the TTL chip that is used as an auxiliary port for some functions, that can be used to select the HD operation mode.

However, IIRC, the only official support for HD/ED is found in the GC/SGC ROM and is based on one of the FDCxxx chips from National Semiconductor. AFAIK these have been obsolete for a LONG time, in fact I seem to recall Stuart Honeyball complaining they were difficult to find when he was doing the SGC. There was a later compatible chip (in a small QFP package) that replaced the olf PLCC one, which incorporated an advanced integrated PLL with no need for external passive components, and also had a FIFO mode for data transfer. THis was also the LAST stand-alone floppy controller ever made (not counting some twighlight technology products i..e. copies from the far east). It may be possible to find this ship from some of the second-hand vendors around the world, it wasn't too expensive even when you could get it originally from NatSemi.

So, from what I can see, your best bet would be to find the chip (DP.... or FDC.... similar number to the one on the GC/SGC but IIRC ends with a 7), a copy of the SGC ROM and do some reverse-engineering or get SMSQ/E sources and have a look in there (since there is a GC/SGC version which incorporates the required driver).