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4.
INTERACTIVE.PROGRAMS
The player's microcomputers, in addition to exerclslng direct
control of the videodisc player's operations, provide the
user with one kilobyte (1024 bytes) of programmable Random
Access Memory (RAM).
This memory space is available for the
storage of user-designed programs to control player operation.
Execution of programs stored in RAM is done by an interpreter
resident in the Erasable Programmable Read Only Memory (EPROM).
There is no provision to access the microcomputer instruction
set directly.
User programs may be loaded into RAM in one of three ways:
from programs coded on the videodisc, manually from a Remote
Control Unit, or under the control of an attached host computer.
A.
Program Dumps
In addition to audio and visual information, a videodisc may
be encoded with one or more pr6gram "dumps."
This is
a computer program of 1022 bytes that is written on Audio
Channel 2 during the disc mastering process.
These program
dumps may be loaded into the player's RAM from the videodisc.
There can be multiple program dumps on the same disc.
Under user program control, each may overwrite 1022 bytes
of the 1024 byte RAM.
B.
Remote Control Unit
Computer programs may be written into RAM through use
of the optional Remote Control Unit (RCU).
The RCU duplicates
the PLAY button on the front panel of the player, and
has many additional keys for controlling the player and
entering program instructions and data.
The RCU permits
a programmer to enter and debug programs prior to their
becoming finalized as program dumps on the videodisc.
Users may also modify existing programs and tailor them
to their unique requirements.
C.
Attached Host Computer
The External Computer Interface (ECI) is an RS232 connector
on the rear of the videodisc player, which permits intercon-
nection of the player and a host computer.
All aspects
of videodisc player operation, including the loading of
user programs into microcomputer RAM, may be performed
via the ECI.
(Interface information is contained in Chapter
III of this manual.)
TPl09 Version 2.0
- 4 -
A,pril 1984
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