W83977ATF Datasheet, PDF (22/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
2.1.6 FDC Core
The W83977ATF 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.
2.1.7 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
MT:
Multitrack
N:
The number of data bytes written in a sector
NCN:
New Cylinder Number
ND:
Non-DMA Mode
OW:
Overwritten
PCN:
Present Cylinder Number
Publication Release Date: April 1998
-21 -
Revision 0.52