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Codemasters CD

289 bytes added, 14:14, 1 July 2010
/* Info Fragments on Spectrum CD Games Pack (Code Masters) (1989) */
== Info Fragments on Spectrum CD Games Pack (Code Masters) (1989) ==
The pack consists of a Audio CD with about 30 spectrum games (each one recorded twice), and a connection cable (cd player's 3.5mm (or 6.3mm via adapter) stereo headphone socket to spectrum 9pin DSUB joystick port) (for Spectrum 128/+2/+3 or 48K with Kempston or sinclair joystick interface), and loading software on tape, once when a game is loaded one can press Q,U,I,T on keyboard to load a new game (without needing to load tape loader again). The loader asked the user to choose to use kempston or sinclair joystick interface. A dissassembly of the loader reveals the following: For kempston: Bit 4 (joystick fire) of port &1f is data. For sinclair: Bit 1 (joystick right/key '2') of port &f7fe is data.
No info if/how the stereo signal is used (maybe one channel used as CLOCK, and the other channel as DATA...?) The cable does reportedly contain a 1bit A/D converter, which is probably a single transistor or so (so it's mono, not stereo?). The CD capacity is said to be "12 Megs" (presumably meaning 12 Megabit = 60 tracks with 25Kbytes each).
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