03.001 What are the correct settings for a ZipGSx? I've tinkered with "CPS Follow", "Counter Delay", and the like but have no idea what I'm actually doing.
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
03.001 What are the correct settings for a ZipGSx? I've tinkered with "CPS Follow", "Counter Delay", and the like but have no idea what I'm actually doing.
Bank C/D cache enable -- Leave this at the default setting (SW1-1 set to ON).
This tells the Zip if it's OK to cache bank-switched RAM (the old language card
area). Zip's own docs say "there is no know software requiring this" but that
it why it's there, in case somebody ever finds software that doesn't like it
you can try setting it the other way.
Paddle Delay lets your paddles or joystick work the way they do on 8-bit Apple
II's or an unaccelerated IIgs. The delay is necessary for playing most 8-bit
games which use paddles or a joystick. Recommended setting is to have the delay
active (SW1-2 set to OFF) unless you feel like experimenting.
AppleTalk or Interrupt Delay should always be disabled (SW1-3 set to ON). The
desktop will run much slower if you enable it. The only reason most people
needed it was for AppleTalk under system 5, and now there is an init on tybalt
that fixes that. System 6 fixed the problem but requires CPS Follow to be
enabled for the fix to work.
Counter Delay is really present just so that the ZipGS can be set to get past
one of the early IIgs diagnostic self-tests. It causes the Zip to
"deaccelerate" (actually all it does is temporarily ignore that any data can be
read from the cache instead of the motherboard) for about 5 milliseconds any
time you read one of the Video Counters. To get pass the particular self-test,
SW1-4 should be set to OFF (delay active). Otherwise, the recommended setting
is SW1-4 set to ON.
CPS Follow should always be enabled (SW1-5 set to OFF). It causes the ZipGS to
auntomatically 'follow' the IIgs-- when it switches to "Normal" speed, the
ZipGS is disabled. This is a requirement for a reasonable amount of timing-
critical software. If you disable CPS Follow you will have problems with Disk ]
['s and System 6's AppleTalk driver and anything else that expects the Zip to
slow down to 1 mhz when the IIgs is instructed to slow down to 1MHz. For
instance, border text demos (like the FTA XMAS demo)
won't work if you have this disabled. Expect weird things to happen if you
play with this one.
ZipGS Enable-- The card should normally be enabled (SW1-6 set to ON).
SW1-7 and SW1-8 should be set to correspond to the size of your ZipGS's cache
memory. (see below)
SW2-1 through SW2-7 control slot delays for Slots 1-7. Set the switch OFF to
enable the delay for the corresponding Slot. This is generally only needed for
a small number of cards that are speed critical but not IIgs-aware. 5.25" disk
interface cards are covered by the CPS FOLLOW option (1-5) if they are in slots
4 to 7.
I have found that it is necessary to enable the delay for slot 6 when using a
3.5" drive connected to the IIgs disk port. There are a few rare cases in which
a long timed operation is performed in fast mode, and the ZIP throws the timing
out unless this delay is enabled. In my case, I had some strange disk errors
with certain disks until I enabled this delay.
Speaker Delay lets "old Apple II" 1-bit sounds play the way they would on 8-bit
Apple II's or an unaccelerated IIgs. The delay is necessary for getting correct
sound from most 8-bit games. I recommend having the delay active (SW2-8 set to
OFF).
Summary
The normally recommended SW1 settings are identical to the
factory default settings except for SW1-4 ...
ON x x x x m m
OFF x x m m
1 2 3 4 5 6 7 8
1- Cxxx/Dxxx Cache: ON= enabled.
2- Defeat Joystick delay: OFF= allow delay.
3- Defeat AppleTalk delay: ON= no delay.
4- Defeat Counter Delay: ON= no delay. Set OFF to pass IIgs
diagnostic self-test #05 ("Speed Test").
5- Defeat CPS Follow: OFF for floppy drives to work.
6- ZipGS enable: ON. (Set OFF to allow powerup boot in
slow mode and use an Init to turn GS back ON.)
7 & 8- Set these to installed Zip cache memory size:
ON ON 8k
ON OFF 16k
OFF ON 32k
OFF OFF 64k
The factory default SW2 settings are ...
ON x x x x x
OFF x x x
1 2 3 4 5 6 7 8
SW2-1 through SW2-7 control whether a card in Slot 1-7 is accessed
at full speed (set ON) or "normal" speed (set OFF)*.
SW2-8 sets Defeat Speaker Delay. To play 'old Apple' music and
effects correctly, the switch should be OFF to permit the delay.
*Note: Whether or not a particular card can work without a slow-down is
something you can determine by experimentaton. This is easiest using the Zip
CDA accessed via the Desk Accessories menu (OpenApple-Control-Escape). The CDA
settings are not permanent. Once you find the settings you like, you can turn
OFF the computer and set the switches on the board to match the settings that
work best.
By: Todd P. Whitesel
Continue to:
My Books
