Sinclair ZX80 / ZX81 / Z88 Forums

Currently working on a spectrum "thing" with a opus discovery attached ( spectrum with soldered on extension on which rests a multi-face and an opus discovery ) .

after finding out what all has been done to it ( it is all mounted inside an old pc case with external keyboard ) ;

the multi-face1( with 4 wires i don't know what they do , but not connected to anything );
the opus discovery ( with several options stripped of the pcb )

some questions ;

as the opus is returning i/o error G ........

can i attach a pc 3,5 " diskdrive ?

What adaptations need to be made to get that working ?

quickdos 2.31 , 6116 memory chip , anything else ??


any help highly appreciated

The best source of help with the Opus Discovery is to work your way through the topics over on WoSf.

And yes I think you can use a PC 3½ inch disk drive. You will have to change either the internal link, zero ohm link or the cable wiring so that the drive responds to the DS0 signal from the Opus Discovery. Normally all 3½ inch disk drives are set to only respond to DS1. If you can change the drive to respond to DS0, then use a straight through cable.

Mark

.

Mark ,

Thanks , encouraging info !!

i am waiting for the 6116 ram to be delivered ,

got 2 pc 3,5 drives to play around with ( remains a single drive configuration ) , and the original sssd drive which generates the G error .


keep you updated !!


quickdos 2.31 is already installed ;

how can i program the 6116 with the parameters needed for a pc 3.5 " diskdrive ?

is there an utility available for download somewere ??

so finally found the programms to format a modern floppy-drive diskette to use with the spectrum !!

altough i now have to use drive " 2 " instead of " 1 ".

I assume that has to do with the difference between the original opus drive and the pc one .

can a " twisted " cable solve this ?
can anyone help me with the last hurdle here ?

jojo wrote: ↑Sat Mar 30, 2024 8:57 pm can a " twisted " cable solve this ?

Not with a twisted cable designed for PCs, as it will also twist the motor on line, but the Opus only has a single (common to all drives) motor on signal, as it uses a Shugart interface.

Shugart interface Floppy Drive Interface
Pin Function
2 /DCD Disk Change Detect (actual function depends on drive)(DENSEL Density Select on some PC drives)
4 /INUSE (actual function depends on drive)(mostly not used on PC)
6 /DS3 Drive Select 3 (PC - not used)
8 /INDEX Index signal
10 /DS0 Drive Select 0 (on a PC Motor Enable 0 / A)
12 /DS1 Drive Select 1 (on a PC Drive Select 1 / B)
14 /DS2 Drive Select 2 (on a PC Drive Select 0 / A)
16 /MO Motor On (on a PC Motor Enable 1 / B)

The rest of the signals are mostly the same for both Shugart and PC.

With a twisted cable for a PC, the last drive (drive 0 / A) has the wires for pins 10, 12, 14 and 16 swapped (the odd wires are all 0V/ground).

Whereas you only want to swap 10 and 12.

Mark

Mark ,


crystal clear !!

i noticed the common motor on , but needed some time to get the ds in my mind.

i now have 1 drive set as ds0 , and that works perfect .
the other drive i have does not want to work with 10 and 12 swapped ( i noticed there is no connection on its pcb for 10 ) , hardwiring 10 input to 12 pcb track also did not give any result ( maybe drive defective ?? )

so discovery is working and even does with dd made hd disks .