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CED VideoDisc and Player Discussion
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cedmagic
Site Admin
Joined: 11 May 2004
Posts: 335
Location: Portland, Oregon
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 Posted: Sun Mar 15, 2020 7:15 pm Post subject: Mostek MK3870 and MK3874 CED Microprocessors |
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The microprocessor at left is the Mostek MK3870 found in all F/G CED players. It was mask-programmed at manufacture to contain the system control assembler code that defines the operation of the CED player.
But during development of the CED system RCA needed to experiment with the system control code, and that was made possible by the MK3874 at right. This uses a piggyback 2716 EPROM that can be removed and programmed over-and-over until the bugs in the code are worked out. An EPROM eraser shines an ultraviolet light through the quartz window on the 2716 to set all the binary bits to one. Then the 2716 is placed in a EPROM programmer to upload the modified code.
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