Re: Help in identifying cards and problems

[nparker@cie-2.uoregon.edu (Neil Parker)]

In article <341ebs$3lt@newsserver.trl.OZ.AU> a.guillaume@trl.oz.au writes:
>[...]
>|Then there is a disk controller card. Says "Disk II Interface Card 650-X104"
>|on the card, and two "Super 5" drives are connected by ribbon cables. I guess
>|that goes in slot 6. Although when I do that, and turn on the computer, the
>|drives click, spin and then spin for ever. Should I suspect a damaged IC
>|on the card ? Or an unsuitable card ?
>
>I should have added that my trials were always done with a disk in the drive.
>Paul suggests that I have a very old disk controller card with the DOS 3.2 ROM
>on it. I will check the firmware ($C600 to $C6FF), but I hasten to add that
>I received the computer with DOS3.3 diskettes, so I assume it would read them.

Another thing to consider:  Are the drives spinning at the right speed?  If
the motor speed is far enough off, they won't be able to read disks.

Fixing thd drive speed might seem to be a chicken-and-egg sort of problem,
since you can't boot any diagnostic software until after the drives are
fixed, but if the drives are anything like Disk ]['s, then there is a way.
If you completely remove the case of a Disk ][ (including the bottom part),
you'll find a wheel on the bottom of the motor marked with two circles of
alternating light and dark marks--the inner circle is labelled "50" and the
outer one is labelled "60".  Turn on the drive, start the motor spinning
(you can do this by typing "CALL-151" and then "C0E9"), and hold the drive
under a flourescent light (if you don't have a flourescent light, your
computer monitor will do, if you fill the screen with a bright image (HGR :
HCOLOR= 3: HPLOT 0,0: CALL 62454)).  If your motor speed is right, one of
the two circles will appear to stand still...the "60" circle will stand
still if your wall power is 60 Hz, and the "50" circle will stand still if
you wall power is 50 Hz.  Adjust the motor-speed screw until the correct
circle appears to stand still.

>|The 3rd card has a Z80 on it, and "CMC 8314" on it. I strongly suspect
>|a CP/M card :-) Which slot should this card go into ? It has a 4-switch DIP
>|switch next to the Z80, what are the settings required (they're all on OFF
>|right now) ?
>
>CP/M card alright. Has someone got info on the switches ?

There are several different, completely incompatible Z80 cards available--
without knowing which one yours is, we can't say definitely what the
switches do.

If your card is a Microsoft Softcard (easily identifiable by the words
"MICROSOFT SOFTCARD" printed in the upper left corner of the component
side), or a clone thereof, then OFF is the correct position for all four
switches (Softcard CP/M doesn't use any of the features that the switches
control).

The Softcard switch settings are as follows:

Switch 1:  OFF = Address translation occurs (Z80 address 0000H corresponds
                 to 6502 address $1000)
           ON =  No address translation (Z80 address = 6502 address)

Switch 2:  OFF = Softcard locks out all other DMA devices when Z80 is active
           ON =  DMA signal from higher slot can interrupt Softcard

Switch 3:  OFF = Softcard ignores NMI
           ON =  NMI causes Z80 non-maskable interrupt

Switch 4:  OFF = Softcard ignores IRQ
           ON =  IRQ causes Z80 interrupt

Softcard CP/M expects to find addresses remapped, so switch 1 should be
left off.  Most Softcard CP/M programs can't handle interrupts, so switches
3 and 4 should be left off too.  Turning switch 2 on probably won't hurt
CP/M, but leaving it off is consistant with CP/M's philosophy of letting
the 6502 handle most I/O.


If the Z80 card is a Softcard (or a clone of it), then it should work in
any slot.  Softcard CP/M is happiest if the card is in slot 4 or slot 7,
since those slots aren't pre-assigned for any other purpose.

              - Neil Parker
--
Neil Parker                 No cute ASCII art...no cute quote...no cute
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