PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 83

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

Bit 4 - Wrong Track
Bit 5 - CRC Error in Data Field
Bit 6 - Control Mark
Bit 7 - Not Used
5.5.4
0
7
This bit indicates whether or not there was a problem
finding the sector because of the track number.
0 - Sector found.
1 - Desired sector not found.
When the FDC detected a CRC error in the correct sec-
tor (bit 5 of the result phase Status register 1 (ST1) is 1),
this bit indicates whether it occurred in the address field
or in the data field.
0 - The CRC error occurred in the address field.
1 - The CRC error occurred in the data field.
When the controller tried to read a sector, this bit indi-
cates whether or not it detected a deleted data address
mark during execution of a READ DATA or scan com-
mands, or a regular address mark during execution of a
READ DELETED DATA command.
0 - No control mark detected.
1 - Control mark detected.
This bit is not used and is always 0.
0
6
Not Used
FIGURE 5-19. ST3 Result Phase Register
The desired sector is not found. The track number
recorded on any sector on the track is different
from the track address specified in the command
phase.
Result Phase Status Register 3 (ST3)
Drive Write Protected
0
5
Not Used
0
4
Track 0
0
3
Not Used
0
2
Head Selected (Command Phase)
0
1
0
0
The Digital Floppy Disk Controller (FDC) (Logical Device 3)
Reset
Required
(Command Phase)
Logical Drive Selected
Result Phase Status
Register 3 (ST3)
83
Bits 1,0 - Logical Drive Selected
Bit 2 - Head Selected
Bit 3 - Not Used
Bit 4 - Track 0
Bit 5 - Not Used
Bit 6 - Drive Write Protected
Bit 7 - Not Used
These two binary encoded bits indicate the logical drive
selected at the end of the command phase.
The value of these bits is the same as bits 1,0 of the SR0
register, described on page 81.
00 - Drive 0 selected.
01 - Drive 1 selected.
10 - If four drives are supported, or drives 2 and 0 are
11 - If four drives are supported, drive 3 is selected.
This bit indicates which side of the Floppy Disk Drive
(FDD) is selected. It reflects the status of the HDSEL
signal at the end of the command phase.
The value of this bit is the same as bit 2 of the SR0 reg-
ister, described on page 81.
0 - Side 0 is selected.
1 - Side 1 is selected.
This bit is not used and is always 1.
This bit Indicates whether or not the head of the select-
ed drive is at track 0.
0 - The head of the selected drive is not at track 0, i.e.,
1 - The head of the selected drive is at track 0, i.e.,
This bit is not used and is always 1.
This bit indicates whether or not the selected drive is
write protected, i.e., the WP signal is active (low).
0 - Selected drive is not write protected, i.e., WP is not
1 - Selected drive is write protected, i.e., WP is active.
This bit is not used and is always 0.
exchanged, drive 2 is selected.
TRK0 is not active.
TRK0 is active.
active.
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