Codemasters CD

2,338 bytes added, 21:06, 10 August 2010
| C---------- Joystick.Pin6 (Fire)
The above circuit was rev-engineered by measuring the resistance between the cable pins, but without opening (=destroying) the moulded plastic connector that houses the original circuit - so far, it isn't fully confirmed if the original cable does really contain the above components(not to mention multimeter tests can't reveal any additional small capacitors). The material of the connector is still unknown, but if it's soft/elastic then it should be extremly easy to peal off the plastic with a knife and pincers, for revealing what is really in there.'''You are welcome to add your own results here if like to combine research with some minor destruction!''' == Audio Signals == Below screenshots are showing some interesting sections of the Tracks on a Codemasters CD (screenshots are based WAV files, recorded from the Spectrum version). * Theoretically the audio signals should contain perfect '''rectangular waveforms''' - the tested WAV files did contain some '''analog dirt''' (the source of that dirt is unknown, either the original CD was mastered using analog equipment, or the CD-to-WAV conversion was done using analog sound input - or both).* As seen on the screenshots, the '''stereo signals''' contain the same data on both left and right channel, so it's effectively a mono signal (without a clock signal or second data bit on one of the channels). <gallery>File:Spectrum Codemasters CD Test Signal (Closeup).png|Track 1 - Test Signal (Closeup)File:Spectrum Codemasters CD Low Speed Block.png|Low Speed BlockFile:Spectrum Codemasters CD High Speed Block.png|High Speed Block</gallery> * Track 1 contains a repeated '''Test Signal''' consisting of two long and two short pulses, intended to be used with the volume calibration function in the cassette loader. The length of the test signal is about 110 seconds, and it's a 'raw' waveform without preceeding header or pilot pulses.* Track 2-33 contain 32 spectrum games (average length 45 seconds each). Track 34 contains a slide show demo (about 390 seconds). Track 35-66 contain backup-copies of Track 2-33.* For whatever reason, the first block on each Track (except Track 1) is '''Low Speed Block''', using about the same pilot/sync/data pulse timings as normal Spectrum Cassette files. However, it is NOT a cassette file (which would consists of TWO such blocks, and which would contain other header/filetype values), the low speed block is around 6 seconds in length.* All further block(s) on each track are '''High Speed Blocks''', pilot/data pulses are shorter as on cassette blocks, the two sync files are longer as on cassettes.
== Info Fragments on Spectrum CD Games Pack (Code Masters) (1989) ==