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CU Amiga Super CD-ROM 1
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CU Amiga Magazine CD-ROM Special Edition (1995)(EMAP Images)(GB)[Issue 1995-11].iso
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emul_1541.lha
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emul_1541
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Emul_1541.doc
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1995-03-01
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Emul_1541 V1.0 by Philippe DEPRUGNEY 1995
SHORT:
------
A program that allows you to plug a C64 computer to your parallel port,
so that you can use your Amiga as a disk drive for the C64, emulating the old
1541 drive.
WHAT'S THE USE ??!?
-------------------
Well, Emul_1541 may be useful to people who have a C64 with a broken
1541. Or to nostalgic C64philes that consider buying an old C64 but cannot
find a 1541...
REQUIREMENTS:
-------------
- an interface that plugs to your parallel port (see 'interface.iff'
for a schematics)
- an Amiga with Kickstart v 2.0+. Any processor should do.
- a C64 :-)
USAGE:
------
Emul_1541 [drive number]
where [drive number] is 8...11 (default is 8)
OPERATION:
----------
Open a Shell and execute 'Emul_1541'. If the parallel port is free and
the interface is plugged in, you can now execute the following commands from
the C64:
-LOAD "<program>",8 (or ",8,1").
-LOAD "$",8. This will load the listing of the current directory
into the C64.
-SAVE "<program>",8 . Speaks for itself.
-LOAD "CD <directory>". This allows you to change the current
directory of the emulator . It will also transfer the listing of the new
directory into the C64.
-you can exit Emul_1541 by typing CTRL C in its window.
MISCELLANEOUS:
--------------
*** Abbreviations are allowed (LOAD "prog*",8 or even LOAD "prog#?",8).
The same goes for the LOAD "CD <directo*>",8 command.
*** special characters:
The '_' Amiga character has a rough equivalent on the C64, which can be
typed using 'SHIFT R'.
The '\' Amiga character stands for the '/' C64 character.
Ex: LOAD "/TURBO_TAPE",8 will start the transfer of '\turbo_tape'
However, you can still type LOAD "CD /" to change the directory to the
parent of the current one.
*** If you type LOAD "<program>",8, 'Emul_1541' will search for
<program> in the current directory, and if it can't find it there, it will
search for it in 'C64:'. You can use this feature to assign 'C64:' to a
directory where you would store the C64 programs you most frequently use.
You can also type the full path name of the file you want.
Ex: LOAD "DH1:C64_GAMES/CHOPLIFTER",8
*** program names are not limited to 16 characters as they are on a
1541 drive. Therefore, you can type 'LOAD "<program>",8' with <program>
having a name longer than 16 characters, and Emul_1541 will transfer it
correctly. However, if you type 'LOAD "$",8', <program> will have its name
truncated to 16 characters in the directory listing.
*** when a directory is created, program sizes and free space are
displayed in blocks, which are worth 254 bytes (on a C64). Due to 16-bit
limitations, the biggest size displayable is 254*65535 = 15.9 Mb. Therefore,
any file or directory free space bigger than 15.9 Mb will not have their size
displayed correctly.
TECHNICAL NOTES:
----------------
*** this program does not multitask while communicating with the C64.
That is because the C64 expects the 1541 to "listen" to its signals all the
time. Therefore, if the emulator was interrupted for more than 20µs, it would
miss some changes of states of the communication signals.
*** 'Emul_1541' uses the timer B of CIA B, which is used by many
time-sensitive programs, such as music players, emulators and some games.
Therefore, you should not run any program of that kind at the same time as my
emulator. Anyway, 'Emul_1541' will warn you if that timer is already
allocated, and will only take possession of it during transfers, not when it
is idle.
*** As the Amiga clock is not updated during transfers, 'Emul_1541'
executes a routine equivalent to 'SetClock LOAD' after every communication
with the C64. I can only hope that this does not cause any problem on an
Amiga without a clock, as I could not test that.
*** I have tried to make 'Emul_1541' compatible with real 1541 drives.
That is, you can daisy-chain the parallel port interface with a 1541 drive,
provided their device numbers are different, and the C64 will be able to
access both drives. Note that multitasking will also be disabled while the
C64 is accessing the real 1541 drive.
*** Sometimes 'Emul_1541' will freeze during a communication sequence
with the C64, because the C64 has sent an unknown command to the emulator.
You can usually get out of that situation by pressing your C64 reset button a
few times. If you do not have a reset button on your C64, I strongly advise
you to install one.
*** Wild star ('*') is allowed during the execution of 'Emul_1541', and
is restored to its prior state after the emulator has exited.
WHAT 'EMUL_1541' CANNOT DO:
--------------------------
*** communicate with fast-loaders: no way. If you have got a FastLoad
cartridge, disable it. Games saved with the Isepic or Freeze Frame cartridges
will not work. The same goes for any program that uses a loading technique
different from the standard one.
*** support commands such as 'VERIFY...' or 'OPEN 1,8,15,"..."'
*** reverse entropy
THANKS TO:
----------
- Cliff DUGAN, whose A64 gave me the inspiration for this
- Peter STUER for DosTrace, which was very useful
TESTED ON:
----------
- A4000/30 with 8Mb FAST RAM, with Kickstart v. 39 and v.37 (using
SKick)
- A1200 with 2Mb FAST RAM
- CD 32 (just joking)
BUGS:
-----
Should you find any, I would like to hear about them. So please send me
a short description of the problem and of your configuration. A picture of
your girlfriend would be much appreciated too.
TO DO:
------
- Isepic files support
- Freeze Frame files support
- '.d64' files support
- FastLoad cartridge support
LEGAL JU-JU
-----------
Emul_1541 is (C) 1995 by Philippe DEPRUGNEY.
This program may be freely distributed, provided the archive and its
contents are not modified in any way. It may be included in any public domain
collection.
This program is also POSTCARDWARE, which means it would be very nice of
you to send me a postcard if you use it. You may also take advantage of that
opportunity to tell me what you like and do not like about Emul_1541, and
what features you would like me to add to it.
Anybody who wants to swap C64 programs (demos, games...) is welcome to
write to me too.
ABOUT THE AUTHOR:
-----------------
You can join me at the following address (sorry, I have no access to
Internet; I know, I live in a cave):
Philippe DEPRUGNEY
20, rue domaine du Château
64230 LESCAR
FRANCE