Tape Drive
The FDC87W21 supports standard tape drives
(1 Mbps, 500 Kbps, 250 Kbps) and new fast
tape drive (2 Mbps). When working at 2 Mbps,
you need to change the crystal to 48 MHz.
FDC Core
The FDC87W21 FDC is capable of performing
twenty commands. Each command is initiated
by a multi-byte transfer from the
microprocessor. The result can also be a multi-
byte transfer back to the microprocessor. Each
command consists of three phases: command,
execution, and result.
Command
The microprocessor issues all required
information to the controller to perform a
specific operation.
Execution
The controller performs the specified operation.
Result
After the operation is completed, status
information and other housekeeping information
is provided to the microprocessor.
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