FDC37C78_07 SMSC [SMSC Corporation], FDC37C78_07 Datasheet - Page 56

• Manufacturer Part Number: FDC37C78_07
• Description: Floppy Disk Controller
• Manufacturer: SMSC [SMSC Corporation]

When both GAP and WGATE bits of the
PERPENDICULAR MODE COMMAND are both
programmed to "0" (Conventional mode), then D0,
D1, D2, D3, and D4 can be programmed
independently to "1" for that drive to be set
automatically to Perpendicular mode. In this mode
the following set of conditions also apply:
1. The GAP2 written to a perpendicular drive
2. The write pre-compensation given to a
3. For D0-D3 programmed to "0" for conventional
during a write operation will depend upon the
programmed data rate.
perpendicular mode drive wil be 0ns.
mode drives any data written will be at the
currently programmed write pre-compensation.
WGATE
0
0
1
1
GAP
0
1
0
1
Conventional
Perpendicular
(500 Kbps)
Reserved
(Conventional)
Perpendicular
(1 Mbps)
Table 29 - Effects of WGATE and GAP Bits
MODE
GAP2 FORMAT
LENGTH OF
56
22 Bytes
22 Bytes
22 Bytes
41 Bytes
FIELD
Note: Bits D0-D3 can only be overwritten when
Software and hardware resets have the following
effect
COMMAND:
1. "Software" resets (via the DOR or DSR
2. "Hardware" resets will clear all bits ( GAP,
registers) will only clear GAP and WGATE bits
to "0". D0-D3 are unaffected and retain their
previous value.
WGATE and D0-D3) to "0", i.e all conventional
mode.
OW is programmed as a "1". If either
GAP or WGATE is a "1" then D0-D3 are
ignored.
on
WRITTEN BY WRITE
the
PORTION OF GAP 2
DATA OPERATION
PERPENDICULAR
19 Bytes
38 Bytes
0 Bytes
0 Bytes
MODE