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CD-i Bits (News about CD-i Emulator)

The horror story behind the product design of CD-i

>> Wednesday, March 3, 2010

Cdifan shared some insight behind the CD-i keyboards on the CD-i Bits blog which I want to save here on Interactive Dreams: The "CD-i Keyboard" is a full PC-AT style keyboard (without a "Windows" key, and using the term "SuperShift" for what is usually called "Alt") that connects to a CD-i player just like any other peripheral. It was intended for the professional market (specifically, the so-called "CD-IX" configuration) and is colored accordingly (whitish). This is the keyboard that the original CD-i keyboard protocol (later called "K-mode" because of it's ASCII "K" device identifier byte) was written for. It transmits key events in two-byte packets at 1200 baud.

The CD-i KeyControl also supports a so-called "T-mode" which uses a different protocol. The keyboard actually masquerades as a graphical tablet with a device identifier byte of ASCII "T". This protocol transmits key events in four-byte packets at 1200 baud.

Why was the "T-mode" introduced when there was already a perfectly usable keyboard device protocol? The reasons for this are arcane, to say the least, and provide a very nice "horror" story about product design and compatibility; it also illustrates the lengths that Philips went to in order to maintain the "All CD-i titles can be used with all CD-i players" principle.

First we need a little background. Most CD-i players have two input ports, usually one on the back and one on the front. Newer players support the use of a splitter cable to connect two peripherals to the front port, in reality these players have two "front" ports that are smartly wired together in a single connector (dual front port support is a feature of the IKAT coprocessor in the newer CD-i players, specifically Mono-III and later).

However, front and back ports are not functionally identical. Back ports are fully bidirectional RS232 ports supporting both serial input and serial output; they are invariably connected directly to the on-chip UART port of the 68070 processor. Front ports are unidirectional; they can only receive serial input and are connected via the SLAVE or IKAT coprocessor (an 68HC05).

The SLAVE processor fully supports the "K" protocol on its single input port, but the IKAT processor only supports it on its secondary port (the one that only becomes accessible when a splitter cable is used). There is no good technical reason for this limitation as far as I know: both ports are supported by software in the IKAT and it should have been easy to support the "K" protocol on both.

Hence the following requirement from the CD-i KeyControl manual:

Splitter cable is required for models CDI 210/40, CDI210/60 and CDI 470/00 and up. (you can see the full manual here).

There is however a complication with the CD-i 450 and FW 380i players (and their variations the CD-i 550 and Magnavox CDI 5000 and CDI 9000): they do not have a back port! Instead one of the two "ports" that make up the front port is connected to the 68070 and thus bidirectional, the other is unidirectional. For some reason the secondary port was chosen to be the bidirectional one, possibly to lessen the load in the main 68070 processor in the usual case or for fail-safety reasons (if a user blows up a port it would tend to be the primary one, which would leave the 68070 port accessible for diagnostics).

The CD-i modem has to be connected to a bidirectional input port, otherwise the CD-i player would not be able to send out data. This means the back port on those players that have it, or the secondary front port on those that do not.

From the above you can deduce that this leaves players without a back port without the possibility to connect a K-mode keyboard while also using a modem! That means that the CD-i 450 and FW 380i players (and their variations) could not be used in the modem + keyboard configuration, which was unacceptable for both marketing and philosophical reasons.

So a workaround was devised. By having the CD-i KeyControl masquerade as a graphical tablet, it could be supported on the primary input port of the IKAT. The coprocessor dutifully reports the "tablet" data to the main processor, which then (using a custom driver that was included on the application disc) transforms it back into keyboard data that the CD-i application can process in the normal way.

When both a modem and a CD-i KeyControl are connected to a CD-i 450 or the FW 380i player, there is no possibility for connecting a wired pointing device (both input ports are in use). These players have no remote (infrared) capability which would make it impossible to "point and click". To remedy this, another workaround was devised. In the T-mode, the function keys F3 to F6 act as cursor keys while the F1 and F2 keys act as button and button 2, respectively

Thanks to CD-i fan

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Games 0-F

3rd Degree - PF Magic
7th Guest, The - Philips Freeland Studios
Accelerator - SPC/Vision
Adventure of the Space Ship Beagle, The - Denshi Media Services
Affaire Morlov, L' - Titus
Alfapet - Adatek
Alice in Wonderland - Spinnaker
Alien Gate - SPC Vision
Alien Odyssee - Argonaut
Aliens Interactive CD-i - Dark Vision Interactive
Ange et le Demon, L' - Smart Move
Apprentice, The - SPC Vision
Apprentice 2, The - Marvin's Revenge - SPC Vision
Arcade Classics - Philips ADS / Namco
Asterix - Caesar’s Challenge - Infogrames
Atlantis - The Last Resort - PRL Redhill (Philips ADS)
Axis and Allies - CapDisc
Backgammon - CapDisc
Battle Chess - Accent Media (for Interplay)
Battleship - CapDisc
Big Bang Show - Infogrames
BMP Puzzle - Circle (for ZYX)
Brain Dead 13 - Readysoft
Burn:Cycle - Trip Media
Caesar's World of Boxing - Philips POV
Caesar's World of Gambling - CD-I Systems
Cartoon Academy - Bits Corporation
CD-i mit der Maus - SPC Vision
CD Shoot - Eaglevision Interactive Productions
Change Angels Kick-off - HMO
Chaos Control - Infogrames
Christmas Country - Creative Media
Christmas Country - The Lost Levels - Creative Media
Christmas Crisis - DIMA
Clue - 3T Productions
Clue 2 - The mysteries continue - 3T Productions
Connect Four - CapDisc
Creature Shock - Argonaut (for Virgin)
Crime Patrol - CapDisc
Crow, The - Philips POV
Cyber Soldier Sharaku - Japan Interactive media
Dame was Loaded, The - Beam Software
Dark Castle - Philips POV
Dead End - Cryo
Defender of the Crown - Philips POV
Deja Vu - Icom Simulations
Deja Vu 2: Lost in Las Vegas - Icom Simulations
Demolition Man - Virgin Interactive Entertainment
Demon Driver - Haiku Studios
Discworld - Teeny Weeny Games
Dimo's Quest - SPC Vision
Domino - Wigant Interactive Media
Down in the Dumps - Haiku Studios
Dragon's Lair - Superclub / INTL CDI
Dragon's Lair 2- Time Warp - Superclub / INTL CDI
Drug wars - Crime Patrol II - CapDisc
Dungeons & Dragons - PF Magic
Earth Command - Visionary Media
Effacer - CapDisc
Escape from Cybercity - Fathom Pictures
Evidence - Microids
Falco & Donjon & The Sword of Inoxybur - BMi / Zephyr Studio
Family Games I - DIMA
Family Games II - Junk Food Jive - DIMA
Felix the Cat - Philips Sidewalk Studio
Flashback - Delphine/Tiertex (for US Gold)
Flinstones Wacky Inventions - Philips Funhouse
Fort Boyard: The Challenge - Microids
Frog Feast - Rastersoft

CD-i Games Index G-M

Go - CapDisc
Golden Oldies - SPC Vision
Golden Oldies II - SPC Vision
Golgo 13 - Japan Interactive Media
Great day at the races, A - CD-I Racing, Dove Films, Total Vision
Guignols de l'Info, Les - Canal+ Multimedia / INTL CDI
Heart of Darkness - Amazing Studio (for Virgin)
Hitchhiker's Guide to the Galaxy, The - Philips Kaleidoscope
Holland Casino CD-i - HMO
Hotel Mario - Philips Fantasy Factory
Inca - Coktel Vision
Inca 2 - Coktel Vision
International Tennis Open - Infogrames
Jack Sprite vs. The Crimson Ghost - PF Magic
Jeopardy - Accent Media
Jigsaw - Novalogic
Joe Guard - DIMA
John Dark: Psychic Eye - CapDisc
Joker's Wild!, The - Accent Media
Joker's Wild Jr., The - Accent Media
Kether - Infogrames
Kingdom - The far reaches - CapDisc
Kingdom 2 - Shadoan - CapDisc
Labyrinth of Crete - Philips Funhouse
Laser Lords - Spinnaker
Last Bounty Hunter, The - CapDisc
Legend of the Fort - Microids
Lemmings - DMA Design / Psygnosis
Lettergreep - Wigant Interactive Media
Lingo - SPC Vision
Link - The faces of evil - Animation Magic
Lion King, The - Virgin Interactive Entertainment
Litil Divil - Gremlin Graphics
Litil Divil 2: Limbo Years - Gremlin Graphics
Lords of the rising sun - Philips POV
Lost Eden - Cryo (for Virgin)
Lost Ride, The - Formula (Lost Boys)
Lucky Luke - The video game - SPC Vision
Mad Dog McCree - CapDisc
Mad Dog McCree II: The lost gold - CapDisc
Magic Eraser - Circle (for ZYX)
Mah-Jong - Japan Interactive Media
Making the Grade - 3T Productions
Man Before Man - Cryo
Marco Polo - Infogrames
Mario Takes America - CIGAM
Master Labyrinth - AVM AG/HQ
Mega Maze - CapDisc
Memory Works, The - Compact Disc Incorporated
Merlin's Apprentice - Philips Funhouse
Microcosm - Philips Freeland Studios
Micro Machines - Codemasters
Monty Python's Invasion from the Planet Skyron - Daedalus CD-i Productions
Mutant Rampage - Body Slam - Animation Magic
Myst - Sunsoft (for Cyan)
Mystic Midway - Rest in pieces - Philips POV
Mystic Midway 2 - Phantom Express - Philips POV

Compact Disc Interactive

Compact Disc Interactive

Games N-Z

Name that tune - Philips Fantasy Factory
New Day - Bits Corporation
NFL Hall of Fame Football - Philips POV
Othello - HMO
Pac Panic - Philips ADS / Namco
Palm Springs Open - ABC Sports / Fathom Pictures
Pool - SPC Vision
Pinball - CapDisc
Plunderball - ISG Productions
Power Hitter - ABC Sports / Fathom Pictures
Power Match - Two's Company
Pursue - BEPL
Pyramid Adventures - Compact Disc Incorporated
RAMRaid - PRL Redhill
Return To Cybercity - Fathom Pictures
Riddle of the Maze, The - Fathom Pictures
Riqa - Bits Corporation
Rise of the Robots - Mirage Technologies
Sargon Chess - Spinnaker
Scotland Yard Interactive - AVM AG/HQ
Secret Mission - Microids
Secret Name of Ra, The
Shaolin's Road - Infogrames
Skate Dude - Viridis
Smurfen, De - De Telesmurf - Infogrames
Solar Crusade - Infogrames
Solitaire - BEPL
Space Ace - Superclub / INTL CDI
Space Ranger - Studio Interactive
Special Operations Squadron - SPC Vision
Sport Freaks - SPC Vision
Star Trek - Philips POV
Star Wars: Rebel Assault - LucasArts
Steel Machine - SPC Vision
Striker Pro - Rage
Strip Poker Live - Greenpig Production
Strip Poker Pro - Interactive Pictures
Super Fighter - The Super Fighter Team / C&E
Super Mario's Wacky Worlds - NovaLogic
Surf City - Philips Sidewalk Studios
Tangram - Eaglevision Interactive Productions
Taco's Toyroom Troopers - Creative Media
Tankdoodle - Creative Media
Tetris - Philips POV
Tetsuo Gaiden - Creative Media
Text Tiles
Thieves' World - Electronic Arts
Tic-tac-toe - BEPL
Tox Runner - ISG Productions
Treasures of Oz - Philips Kaleidoscope
Ultra CD-i Soccer - Krisalis
Uncover featuring Tatjana - SPC Vision
Uninvited - Icom Simulations
Video Speedway - ISG Productions
Vinnie the Pinguin - Pandemonium Labs
Voyeur - Philips POV
Voyeur 2 - Philips POV
Whack-a-Bubble - Creative Media
What's it worth - Marshall Cavendish Multimedia / Spice
Who shot Johnny Rock? - CapDisc
Wordplay - BEPL
World Cup Golf - US Gold
Zaak Sam, De - Toneelschool NL
Zelda - The wand of Gamelon - Animation Magic
Zelda's Adventure - Viridis
Zenith - Radarsoft
Zombie Dinos From The Planet Zeltoid - Philips POV

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