W83877TF/W83877TG
Publication Release Date: May 2006
-17- Revision 0.7
5.1.6 Tape Drive
The W83877TF/TG supports standard tape drives (1 Mbps, 500 Kbps, 250 Kbps) and new fast tape
drive (2M bps).
5.1.7 FDC Core
The W83877TF/TG 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.
5.1.8 FDC Commands
Command Symbol Descriptions:
C: Cylinder number 0 - 256
D: Data Pattern
DIR: Step Direction
DIR = 0, step out
DIR = 1, step in
DS0: Disk Drive Select 0
DS1: Disk Drive Select 1
DTL: Data Length
EC: Enable Count
EOT: End of Track
EFIFO: Enable FIFO
EIS: Enable Implied Seek
EOT: End of track
FIFOTHR: FIFO Threshold
GAP: Gap length selection
GPL: Gap Length
H: Head number
HDS: Head number select
HLT: Head Load Time
HUT: Head Unload Time
LOCK: Lock EFIFO, FIFOTHR, PTRTRK bits prevent affected by software reset
MFM: MFM or FM Mode
