pc8477b National Semiconductor Corporation, pc8477b Datasheet - Page 17

• Manufacturer Part Number: pc8477b
• Description: Advanced Floppy Disk Controller
• Manufacturer: National Semiconductor Corporation

4 0 Command Set Description
SCAN EQUAL
Command Phase
Execution Phase
controller is compared to data read from disk
Result Phase
SCAN HIGH OR EQUAL
Command Phase
Execution Phase
controller is compared to data read from disk
Result Phase
IPS
IPS
MT
MT
MFM
MFM
X
X
End of Track Sector Number
End of Track Sector Number
Intersector Gap Length
Intersector Gap Length
SK
SK
X
X
Drive Head Number
Drive Head Number
Status Register 0
Status Register 1
Status Register 2
Status Register 0
Status Register 1
Status Register 2
Bytes per Sector
Sector Step Size
Bytes per Sector
Bytes per Sector
Sector Step Size
Bytes per Sector
Data transferred from system to
Data transferred from system to
Sector Number
Sector Number
Sector Number
Sector Number
Track Number
Track Number
Track Number
Track Number
Head Number
Head Number
X
X
1
1
X
X
0
1
HD
HD
0
1
DR1
DR1
0
0
(Continued)
DR0
DR0
1
1
17
SCAN LOW OR EQUAL
Command Phase
Execution Phase
controller is compared to data read from disk
Result Phase
SEEK
Command Phase
Note Last Command Phase byte is required only if ETR is set in Mode
Execution Phase Disk drive head is stepped in or out to a
programmable track
No Result Phase
SENSE DRIVE STATUS
Command Phase
Execution Phase Disk drive status information is detected
and reported
Result Phase
SENSE INTERRUPT
Command Phase
Execution Phase Status of interrupt is reported
Result Phase
Note Third Result Phase byte can only be read if ETR is set in the Mode
MT
IPS
X
0
0
0
X
Command
Command
MSN of Track Number
MSN of PTR
0
X
MFM
0
X
0
X
0
X
Present Track Number (PTR)
End of Track Sector Number
0
Intersector Gap Length
SK
X
Drive Head Number
New Track Number
Status Register 0
Status Register 1
Status Register 2
Status Register 3
Status Register 0
Bytes per Sector
Sector Step Size
Bytes per Sector
X
X
Data transferred from system to
0
0
Sector Number
Sector Number
Track Number
Track Number
Head Number
0
1
X
0
X
X
0
X
1
1
0
HD
X
1
0
1
HD
0
HD
0
0
1
0
DR1
DR1
0
0
DR1
1
0
0
0
DR0
DR0
DR0
0
1
1
0
0
0