W83977F Datasheet, PDF (31/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
PRELIMINARY
2.1.6 FDC Core
The W83977F/ AF 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:
DS1:
Disk Drive Select 0
Disk Drive Select 1
DTL:
EC:
Data Length
Enable Count
EOT:
End of Track
EFIFO:
EIS:
Enable FIFO
Enable Implied Seek
EOT:
FIFOTHR:
End of track
FIFO Threshold
GAP:
GPL:
Gap length selection
Gap Length
H:
Head number
HDS:
HLT:
Head number select
Head Load Time
HUT:
LOCK:
Head Unload Time
Lock EFIFO, FIFOTHR, PTRTRK bits prevent affected by software reset
MFM:
MT:
MFM or FM Mode
Multitrack
N:
The number of data bytes written in a sector
NCN:
ND:
New Cylinder Number
Non-DMA Mode
OW:
PCN:
Overwritten
Present Cylinder Number
Publication Release Date: March 1998
-20-
Revision 0.58