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Path: ns-mx!uunet!wupost!waikato.ac.nz!comp.vuw.ac.nz!actrix!David.Empson
From: David.Empson@actrix.gen.nz (David Empson)
Newsgroups: comp.sys.apple2
Subject: Re: Speaking of the Zip...
Message-ID: <1991Nov12.135052.365@actrix.gen.nz>
Date: 12 Nov 91 13:50:52 GMT
References: <1991Nov11.185126.28247@usenet.ins.cwru.edu>
Organization: Actrix Information Exchange, Wellington, New Zealand
Lines: 148
Comment-To: bb252@cleveland.Freenet.Edu
In article <1991Nov11.185126.28247@usenet.ins.cwru.edu> bb252@cleveland.Freenet.Edu (James L. Brookes) writes:
>
> The only drawback I find to the Zip is that the CDA is not in the
> firmware, so you have to boot up GS/OS to access it. While the speed of
> bootup now makes that less of a problem, I do remember hearing of some
> p8 util that would load CDAs. If there is such a beast, I would
> *really* love to have it. There are some games that are just *too*
> fast with the Zip in, it would be nice to play those at say 7 mhz or
> something.
>
> [High Speed at last, and loving every second of it:^]
Agreed!!!
The program you want is called P8CDA, and it is published by:
Roger Wagner Publishing, Inc.
1050 Pioneer Way, Suite P
El Cajon, California 92020
619/442-0522
P8CDA is a ProDOS-8 system file that installs all CDAs it finds in the
SYSTEM/DESK.ACCS directory, then runs the second .SYSTEM file.
The package includes a CDA screen blanker. I don't know the price,
but it should be no more than US$25.
An alternative would be to write a ProDOS-8 SYS file that can set the
speed of the ZIP and perform the other operations that the CDA
supports. It is very easy to write a program to 'enable' and
'disable' the ZIP - I have written a couple called FAST and SLOW.
All you need is details of the I/O addresses used by the ZIP.
Here is SLOW:
2000: A9 50 LDA #$50
2002: 8D 5A C0 STA $C05A ; write $50 to $C05A four times to
2005: 8D 5A C0 STA $C05A ; enable access to the ZIP registers
2008: 8D 5A C0 STA $C05A
200B: 8D 5A C0 STA $C05A
200E: 8E 5A C0 STZ $C05A ; write $00 to $C05A to disable the ZIP
2011: 0A ASL
2012: 8D 5A C0 STA $C05A ; write $A0 to stop accessing the ZIP
2015: 20 00 BF JSR $BF00 ; Do a ProDOS QUIT call
2018: 65 $65
2019: 1D 20 $201D
201B: 00 00 BRK $00
201D: 04 00 00 00 00
Just type in the hex codes on the left, and use the following commands
to save it:
CREATE SLOW,TSYS
BSAVE SLOW,TSYS,A$2000,L$22
To write FAST, simply change one byte:
200F:5B
(this changes the STZ $C05A to STZ $C05B)
CREATE FAST,TSYS
BSAVE FAST,TSYS,A$2000,L$22
Now, before you run your game, you boot ProDOS-8 and run SLOW. After
you've finished with the game, boot ProDOS-8 and run FAST to resume
full speed operations (or boot GS/OS and use the CDA).
Here is the full set of ZIP registers, for those who are interested
(others can skip the rest of this article):
ZipChip GS Special Registers Ex ZIP Technology, 12 October 1990
Registers must be unlocked before they can be accessed (see $C05A).
Locking them will re-enable the annunciators.
Writing to any I/O location $C058-$C05F (whether registers are locked or
unlocked) will reset delay in progress.
$C058 R No operation
$C058 W Write any value to force poweron/reset bit to COLD (forces next
reset to restore ZIP registers to defaults/switch settings).
$C059 R/W 76543210
*....... Bank Switch Language Card cache disable=1/enable=0?
.*...... Paddle delay (5 ms) disable=0/enable=1 $C070/$C020
..*..... External delay (5 ms) disable=0/enable=1
...*.... Counter delay (5 ms) disable=0/enable=1 $C02E/$C07E
....*... CPS follow disable=0/enable=1
.....*.. Last Reset warm? READ ONLY
......*. Hardware DMA READ ONLY
.......* non-GS (0)/GS (1) READ ONLY
$C05A R 76543210
****.... Current ZIP Speed, 0=100%, F=6.25%, in 6.25% increments
....1111
$C05A W Write values as follows:
$5x Unlock ZIP registers (must write 4 times)
$Ax Lock ZIP registers
other Force ZIP to follow system clock (i.e. disable card)
$C05B R 76543210
*....... 1msclk - clock with 1 ms period
.*...... cshupd - Tag data at $C05F updated (read $C05F to reset)
..*..... Bank Switch Language Card cache (0), don't (1)
...*.... Board disable - 0=enabled, 1=disabled
....*... delay in effect (0=ZIP, 1=Slow)
.....*.. rombank (0/1) - not in development version
......** Cache RAM size (00=8k, 01=16k, 10=32k, 11=64k)
$C05B W Write any value to force ZIP to current speed (i.e. enable card)
$C05C R/W 76543210
*******. Slot 7-1 delay enable (all slots 52-54 ms)
.......* Speaker delay enable (5 ms)
$C05D R Current 65816 bank
$C05D W 76543210
****.... Set ZIP speed, 0=100%, F=6.25%, in 6.25% increments
....**** Don't care
$C05E R Read last Tag data written and force the next write to
create a trash tag value.
$C05E W No operation
$C05F R Read last Tag data written and reset cshupd. Note: apparently
any write to a ZIP register (unlocked) will clear cshupd, but cshupd says
that this location must be read.
$C05F W No operation
I got this information from ZIP Technology (with many thanks).
--
David Empson
EMPSON_D@kosmos.wcc.govt.nz
David.Empson@bbs.actrix.gen.nz