PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 86

• Manufacturer Part Number: PC87307VUL
• Description: PC87307/PC97307 Plug and Play Compatible and PC97 Compliant SuperI/O
• Manufacturer: National Semiconductor

www.national.com
5.7 THE FDC COMMAND SET
The first command byte for each command in the FDC com-
mand set is the opcode byte. The FDC uses this byte to de-
termine how many command bytes to expect.
If an invalid command byte is issued to the controller, it im-
mediately enters the result phase and the status is 80h, sig-
nifying an invalid command.
Table 5-9 shows the FDC commands in alphabetical order
with the opcode, i.e., the first command byte, for each.
In this table:
Section 5.7.1 explains some symbols and abbreviations
you will encounter in the descriptions of the commands.
All phases of each command are described in detail, start-
ing with Section 5.7.2, with bitmaps of each byte in each
phase.
Only named bits and fields are described in detail. When a
bitmap shows a value (0 or 1) for a bit, that bit must have
that value and is not described.
•
•
•
MT is a multi-track enable bit (See “Bit 7 - Multi-Track
(MT)” on page 96.)
MFM is a modified frequency modulation parameter
(See “Bit 6 - Modified Frequency Modulation (MFM)”
on page 90.)
SK is a skip control bit. (See “Bit 5 - Skip Control (SK)”
on page 96.)
86
CONFIGURE
DUMPREG
FORMAT TRACK
INVALID
LOCK
MODE
NSC
PERPENDICULAR
MODE
READ DATA
READ DELETED
DATA
READ ID
READ TRACK
RECALIBRATE
RELATIVE SEEK
SCAN EQUAL
SCAN HIGH OR
EQUAL
SCAN LOW OR
EQUAL
SEEK
SENSE DRIVE
STATUS
SENSE INTERRUPT
SET TRACK
SPECIFY
VERIFY
VERSION
WRITE DATA
WRITE DELETED
DATA
Command
TABLE 5-9. FDC Command Set Summary
MT
MT
MT
MT
MT
MT
MT
MT
7
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
MFM
MFM
MFM
MFM
MFM
MFM
MFM
MFM
MFM
MFM
MFM
DIR
6
0
0
0
0
0
0
0
0
0
0
0
0
Invalid Opcode
Opcode
SK
SK
SK
SK
SK
SK
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
4 3 2 1 0
1 0 0 1 1
0 1 1 1 0
0 1 1 0 1
1 0 1 0 0
0 0 0 0 1
1 1 0 0 0
1 0 0 1 0
0 0 1 1 0
0 1 1 0 0
0 1 0 1 0
0 0 0 1 0
0 0 1 1 1
0 1 1 1 1
1 0 0 0 1
1 1 1 0 1
1 1 0 0 1
0 1 1 1 1
0 0 1 0 0
0 1 0 0 0
0 0 0 0 1
0 0 0 1 1
1 0 1 1 0
1 0 0 0 0
0 0 1 0 1
0 1 0 0 1