Atari800 for SEGA Dreamcast
===========================

Usage
-----

The mapping of the connected DC controllers to the Atari joysticks is
as follows:

The leftmost controller is joystick #1. Then, while going to the
right, the next controller is joystick #2. The next one is joystick
#3. Joystick #4 is the rightmost controller if all 4 controller jacks
are in use.

The 1st (leftmost) controller is used to provide the console keys
(start, select, etc).

The mapping for the 1st controller is as follows (for computers, not
5200):

	    B		-	START
				(maps to ESC key while being in the
				emulator menu)
	    Y		-	SELECT
	    X		-	OPTION
	    A		-	joystick button

	    L		-	emulator menu
	    R		-	enter keyboard emulation screen

	    Start	-	warm boot (reset key)
	    Start + X	-	cold boot (power cycle)

	    joypad	-	joystick directions

On the other controllers only the joypad and A are used.

L and R are mapped to Z and C buttons on the Arcade Stick.
While in the emulator menu, pressing Start causes the Dreamcast to
reboot.

The Dreamcast keyboard is also supported:
	    F1		-	emulator menu
	    ESC		-	leave menu/go back

	    F2		-	OPTION
	    F3		-	SELECT
	    F4		-	START

	    F5		-	cold boot (power cycle)
	    F12		-	Dreamcast reboot

	    End		-	HELP
	    Pause	-	break
	    S3		-	Atari key

In 5200 mode the A, B, X, and Y buttons of the controllers are
redefined:
	    Y		-	Start key (only the 1st controller)
	    B		-	4 (starts some games, "  "  "  "  )
	    X		-	joystick button #2
	    A		-	joystick button #1

In 800 mode up to 4 paddles are supported (only 2 tested by
me). A is the paddle trigger.

Also in 800 mode, X, Y, and B can be redefined to generate keys from
the keyboard. If this is enabled, Option, Select, and Start keys can
be entered in the keyboard emulation screen.

In order to use paddles, you have to switch on the "Emulate paddles"
setting in the "AtariDC Settings" menu.


Compiling
---------

You will need a SH4 cross compiler and the KallistiOS library
(http://cadcdev.sourceforge.net).

See the README included in KallistiOS for information on how to build
the cross compiler and library.

After you have installed the cross compiler and compiled KOS, adapt
src/dc/Makefile.dc to your environment. You'll probably have to change
the SHBASE and KOS variables in dc/Makefile.dc to point to your
compiler and KOS locations, respectively.

Then you can build the executable, "atari800.elf". In the atari800 src
directory type

	make -f dc/Makefile.dc

to compile it. Use GNU make.


CD setup
--------

After you have compiled the atari800.elf file, you may want to make a
CD image which contains the a8 binary files and disk images you'd like
to use.

If you don't want to burn a CD, but have a serial, broadband, or lan
adapter, then you can use the dc-load tool to transfer the ELF
executable to the Dreamcast and run it. The dc-load tool is included
in the KOS library. You need to create a CD ISO image, as described
below, and use the -i switch to dc-load, to emulate this image over
the the dc-load connection.

If you create a real CD, there is one more step needed additionally to
the steps described below: You need to put the atari800 executable
file as boot file onto the CD. For information to create Dreamcast
bootable CDs see http://mc.pp.se/dc/cdr.html. Convert the atari800.elf
to a plain binary file with something like "sh-elf-objcopy -R .stack
-R .comment -R .bss -R .sbss -O binary atari800.elf atari800.bin" and
then scramble it.

The CD must contain the atari800.cfg file in the root directory. If
you use the supplied demo atari800.cfg file, the Atari BIOS ROMS also
have to be in the CD root directory. If you don't like this layout,
change it and adapt the atari800.cfg file accordingly.

Please note that paths in the atari800.cfg must start with /cd to
reference the CD, so for a /roms directory on the CD the atari800.cfg
entry must be ROM_DIR=/cd/roms.

If you like to have a .com/.exe/.atr to be started automatically, copy
it into the CD root directory and name it autorun.com / autorun.exe /
autorun.atr, respectively.


Bugs/ToDos
----------

* There are still sound glitches on some games.
* There might be display jitter in scrolling games in NTSC mode.
* Run ATRs read-write from vmu.
* More than 2 controllers are not well tested.
* Improve keyboard support
* Mouse support?


Help/Problems/Bugs/Suggestions
------------------------------

Please contact me at chris@groessler.org or
groessler_christian@yahoo.de. I'm also monitoring the official
Atari800 mailing list (atari800-users@lists.sourceforge.net).

The newest version is at

    ftp://ftp.groessler.org/pub/chris/dreamcast/atari800dc


Have fun with it,
Christian Groessler

Last change: 27-Apr-2015.