Data, control commands and a VCC/RDY signal from the
Computer Console enter the Disk Drive through either
of the two serial I/O connector jacks at the rear of
the Drive chassis.
Each of the three main signal input lines are
buffered for static protection and to reduce power
consumption on the 800 I/O lines.
Data is sent by the Console in serial format, with
checksums accompanying the data for validity
verification.
The Drive’s PIA is primarily a buffering and signal
formatting device, with no decision making or
computational capability. It is responsible for the
following:
•Applying the Console’s serial outputs to the Data
2nd Address Busses when requested by the Drive’s
Microprocessor Unit (NW).
•Assisting in the control of the Read/Write and
Erase head position by buffering commands sent to
the Stepper Motor Logic.
•Assisting in control of the Diskette Drive Motor
Logic.
•Providing 128 bytes of RAM for temporary storage
of status information and data sent by the Data
Interface Section for application to the MPU.
The MPU provides the primary decision making and
computational capabilities for the Disk Drive. The
Drive’s MPU is responsible for the following:
•Controlling data transfers, through its control
over the Common Data and Address Busses.
•Interpreting and controlling the accomplishment
of Console commands (temporarily stored in FLXM)
and Disk Drive operating instructions
(permanently stored in ROM).
•Controlling the Stepper, Disk Drive and Motor
Logics, which are buffered by the PIA.
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