Short:        Sega Mega Drive emulator for MNT ZZ9000
Author:       Xanxi
Uploader:     Hakim Hassani <hassani hakim gmail com>
Type:         misc/emu
Version:      1.1
Requires:     MNT ZZ9000, XX19 firmware from Xanxi's branch or compatible, Picasso96, AHI
Architecture: m68k-amigaos >= 3.0

ZZPicoDrive 1.1 - Genesis / Mega Drive Edition
------------------------------------------------

ZZPicoDrive is a Sega Mega Drive / Genesis emulator for Amiga classic
systems equipped with an MNT ZZ9000.

The 68k Amiga side handles the launcher, file access, RTG display,
input, audio output, SRAM and savestates. The emulation core runs on
the ZZ9000 ARM Core1 and renders directly into ZZ9000 RTG memory.

The emulator runs as a ZZ9000 ARM blob, controlled by a native AmigaOS
68k program.

Features
--------

- Sega Mega Drive / Genesis emulation using PicoDrive.
- ARM Core1 execution on the ZZ9000.
- Native AmigaOS launcher with ROM selection and options.
- Direct RTG rendering through Picasso96.
- Low 68k CPU usage.
- PAL and NTSC support.
- AHI stereo audio backend.
- Direct Paula DMA audio backend.
- Keyboard controls.
- lowlevel.library / CD32-style controller support.
- DB9 joystick support.
- Two-player support.
- SRAM support for games that use battery backup.
- Savestates.
- Embedded ARM blob in the executable.

Requirements
------------

- Amiga with MNT ZZ9000.
- Firmware XX19 from Xanxi's branch, or later XX firmware, or any
  firmware explicitly compatible with ZZPicoDrive.
- Matching zz9000.card file.
- Picasso96 RTG setup.
- Picasso96 mode supporting 320x240 in 32-bit colour.
- AHI installed if using the AHI audio backend.

ZZPicoDrive is not compatible with MNT firmwares 1.0 to 1.13.
ZZPicoDrive is not compatible with MiDWaN / BlitterStudio firmwares.

This is not a criticism of other ZZ9000 firmware branches. ZZPicoDrive uses
specific low-level Core1, DDR memory mapping and RTG/PAN mechanisms required
by this application. Other firmware branches may work only if they explicitly
provide a compatible interface.

The firmware is not included in this archive.

Download the XX19 firmware and matching zz9000.card from GitHub:

  https://github.com/Xanxi-Amiga/XACP-V1/releases/tag/XX19_firmware

Do not mix BOOT.BIN, zz9000.card and ZZPicoDrive executables from
different packages. A mismatched firmware/card/executable set may boot
but fail at runtime.

ROM format
----------

ZZPicoDrive loads raw Mega Drive / Genesis ROM images in binary format:

  .bin
  .gen
  .md

Compressed archives such as .zip are not supported.

Interleaved .smd files are not supported either. Please decompress or
convert them to raw .bin format before use.

Audio
-----

ZZPicoDrive produces 16-bit stereo PCM audio at 22050 Hz.

The Mega Drive audio emulation, including YM2612 FM and PSG, runs on
the ZZ9000 ARM side. The ARM writes the stereo PCM stream into shared
memory, and the 68k side plays it back.

Three audio modes are available:

AHI
  16-bit stereo output through AHI. This works with any AHI-supported
  audio hardware, including Paula, sound cards and Prisma. AHI must be
  installed.

Paula DMA
  Direct playback through Paula channels AUD0/AUD1, bypassing AHI.
  This backend does not require AHI and provides direct Paula output.

None
  Audio disabled.

Controls
--------

ZZPicoDrive supports several input methods selectable from the launcher:

Keyboard
  Cursor keys          Direction pad
  Numeric keypad 1     Button A
  Numeric keypad 2     Button B
  Numeric keypad 3     Button C
  Return               Start

DB9 joystick
  Standard Amiga joystick ports can be used through the DB9 input mode.
  Direction and fire buttons are mapped to the Mega Drive pad.

CD32 / USB controllers through lowlevel.library
  CD32-style pads and compatible USB controllers can be used through
  lowlevel.library when supported by your Amiga setup.

Two-player support
  Two-player support is available when suitable input sources are selected
  for player 1 and player 2.

Hotkeys
-------

Shift + Esc      Quit emulator

F1-F5            Load savestate slot 1-5
Shift + F1-F5    Save savestate slot 1-5

Sources
-------

The source code for the ZZ9000 / Amiga port will be made available on
GitHub after cleanup.

This cleanup step is only meant to separate release code from temporary
debugging code and work-in-progress experiments.

Notes
-----

No Sega / Mega Drive / Genesis ROMs are included.

Only use ROM files you legally own.

If the emulator does not open the display, check that your ZZ9000
Picasso96 configuration has a valid 320x240x32 RTG mode.

A High Colour Workbench screen is not enough. ZZPicoDrive needs a real
32-bit / True Colour ZZ9000 RTG mode.

Credits
-------

ZZ9000 / Amiga port, launcher, ARM integration, audio/video/input/save
handling:

  Xanxi

Emulation core:

  PicoDrive by notaz and contributors

See included license files for third-party components.