Zenith H-100 - Block Diagram Description

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BLOCK DIAGRAM DESCRIPTION
Refer to the H-207 block diagram as you read the following.
The H-207 Floppy Disk controller board consists of seven
major sections: the bus interface, the status port, the
control latch, the 1797 floppy disk controller, the data
separation & write precompensation circuits, and the two
drive interfaces.
The bus interface is made up of two octal bus buffers, an
octal tri-state latch, an address comparator, and some
miscellaneous enabling circuitry. These components
interface the H-207 to the S-100 bus in the H/Z-100.
The status port is a read-only device that tells the CPU
the status of the disk drives and the controller. This
includes track density, number of recording sides to the
disk, and if precompensation is being used.
The control latch accepts commands to the disk drives such
as DRIVE SELECT, 5" FASTEP, and others that have to do with
the selection and mode of the drives.
The 1797 controller controls the placement of information
on the diskette. That is, the movement of the drive head,
the formation of written data, and the separation of the
read data is controlled by the 1797.
The data separation and write precompensation circuitry
control how the data is read to or written from the
di sket te . It does thi s by se parati ng the data from the
clock signal during read operations and precompensating
data during the double-density write operations.
The 8" and 5.25" drive interfaces include buffers and filter
circuitry. Up to four drives can be connected to each
interface.
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