CDi_MiSTer

A repo dedicated to create an FPGA implementation of the Philips CD-i to be usable for the MiSTer FPGA project. As every Philips CD-i player has a different hardware, this project focuses on reverse engineering the "Mono I" PCB. This mainboard is used in models like the 210/00, 210/05 or 220/20.

This repository is very experimental! Use at your own risk!

The first games are booting. Expect a certain amount of bugs!

Usage

Place cdi200.rom as boot0.rom in /media/fat/games/CD-i. Place zx405042p__cdi_slave_2.0__b43t__zzmk9213.mc68hc705c8a_withtestrom.7206 as boot1.rom next to it.

The save files containing the NvRAM is compatible with the CD-i emulation of MAME.

Digital gamepads, Analog gamepads and mice are supported for use with this core. To play a title, load a CD and press on the play button at the start screen. CD images can be stored as CHD or CUE/BIN format.

Status

Core Utilization:

Logic utilization (in ALMs)  13,425 / 41,910 ( 32 % )
Total registers              15587
Total block memory bits      630,471 / 5,662,720 ( 11 % )
Total DSP Blocks             66 / 112 ( 59 % )

TODOs in order of priority

• Find a better solution for reducing CPU speed
• Fix regression: Audio hiccups during Philips Logo in Burn:Cycle
  • A workaround is CPU overclocking
• Investigate mysterious non loading behavior
• Investigate input responsiveness (skipped events?)
• Investigate graphical glitch on the left edge in "Alice in Wonderland" and "Laser Lords"
• Investigate graphical glitch at the bottom of the screen in Kether during pause
• Investigate screeching sound effect in the menu of "Golf Tips"
• Fix hang on audio track stop or change in media player
• Investigate "Gray border glitch" at the top of "Myst" gameplay (seems to be only one plane)
• Fix reset behaviour (Core is sometimes hanging after reset)
• Add auto start of titles using front panel "Play" button
• Fix servo behaviour of always detecting a CD-i disc
• Investigate desaturated colors / low contrast in "Photo CD Sample Disc"
  • Probably fixable with 16-235 to 0-255 scaling
  • More investigation needed
• MCD212: Add RGB555
  • Fixes DYUV Test on "Validation Disc"
• Find a solution for the video mode reset during system resets
  • The ST flag is the issue here, causing a video mode change
• Add SNAC support (IR remote + wired controller)
• Refurbish I2C for the front display and show the content as picture in picture during changes?
  • It might not even be required at all.

Expected checksums of roms

This core is tested with these ROMs:

2969341396aa61e0143dc2351aaa6ef6  cdi200.rom
3d20cf7550f1b723158b42a1fd5bac62  zx405042p__cdi_slave_2.0__b43t__zzmk9213.mc68hc705c8a_withtestrom.7206

Due to legal reasons, these files must be sourced separately.

Used resources

This MiSTer core would've probably never been possible without the reverse engineering efforts of certain people. Thanks to CD-i Fan for the insights into his closed source CD-i Emulator. Also Thanks to MooglyGuy, which took on the task of implementing a CD-i emulator into MAME, which I used to analyse the program flow of the CD-i boot process.

• https://github.com/TobiFlex/TG68K.C
• https://opencores.org/projects/68hc05
• https://github.com/cdifan/cdichips
• http://www.icdia.co.uk/microware/index.html
• https://github.com/Stovent/CeDImu/blob/master/src/CDI/OS9/SystemCalls.hpp

FAQ, Issues and Quirks

The production quality of the CD-i hardware and the software running on it is sometimes questionable. For this reason, I've created a small list of some known quirks, someone might suspect of being caused by emulation errors but are also present on the real machine.

• Is the "Digital Video Cartridge" supported?
  • No! Please stop asking!
  • Potential development on the DVC might only start after everything works without bugs on the base machine.
• The map of "Zelda - Wand of Gamelon" has micro jitter during scrolling
  • This also happens on real 210/05 hardware
• "Hotel Mario" seems to have the first samples of every ingame song repeated
  • You have good ears as it is barely noticeable. This also happens on real hardware.
• Some earlier CD-i titles have both stereo channels swapped
  • Yes, according to an internal memo from Philips there were manufacturing issues and some early players have the left and right channel swapped. This might explain discrepancies.
  • One known quirk is inverted stereo on the "Philips Logo Jingle" of "Zelda - Wand of Gamelon"
• During the rotating transition in "Myst" there are glitched lines at the bottom
  • This also happens to some extent on a real 210/05 hardware and is caused by a misplaced Video IRQ The video data is changed while it is displayed.
• When I load a save game in "Burn:Cycle" it plays a short and unclean loop of noise until I do something
  • I thought that was a bug in the core at first too. However, it is actually like this on a real CD-i too.
• The music of Burn:Cycle sometimes has "pops" and "clicks"
  • This game is special. It doesn't play music from CD like most games for this system would do.
  • Small loops of sampled music are loaded from CD, stored in memory and randomly concatenated together to create the background music. These samples are sometimes not very "loopable" creating a pop at looping points.
  • This issue is reproducible on a real 210/05 as well
• The music during the Philips Logo animation of Burn:Cycle has broken audio
  • This issue is reproducible on a real 210/05 as well
  • The problem can be fixed by overclocking the CPU
• Burn:Cycle - Random flickering animated text in front of the "Psychic Roulette" credit card terminal
  • This actually happens on the real machine. I also thought this might be a CPU speed issue, considering that the flickering disappears if the CPU is slightly overclocked.
• Flashback: The audio and video during the intro are asynchronous
  • This curiously happens on the real machine as well and doesn't depend on 50 or 60 Hz
• When dying in "Zelda's Adventure" the accompanying sound effect doesn't match the audio data on CD
  • Good catch! This is a programming error which can be reproduced on a real CD-i 210/05 as well, which causes the audio playback to start one sector too late.
  • The same phenomenon exists in the "Help cutscene" of "Zelda - Wand of Gamelon"
    • It is not audible in that game, because of silence in the beginning