W83787IF Datasheet, PDF (69/123 Pages) Winbond – WINBOND I/O WITH SERIAL-INFRARED SUPPORT

W83787IF
7 65 4 3 21 0
IDETRI
FDCTRI
IDEPWD
FDCPWD
FIPURDWM
SEL4FDD
OSCS2
Reserved
Bit 7: Reserved
OSCS2 (Bit 6): This bit and OSCS1, OSCS0 (bit 1, 0 of CR0) select one of the W83787IF's
power-down functions. Refer to descriptions of CR0.
SEL4FDD (Bit 5): Selects four FDD mode
0
Selects two FDD mode (see Table 7-2)
1
Selects four FDD mode
DSA , DSB , MOA and MOB output pins are encoded as show in Table 7-3 to select
four drives.
Table 7-2
DO REGISTER ( 3F2H )
Bit 7 Bit 6 Bit 5 Bit 4 Bit 1 Bit 0
00 0 0 0 0
00 0 1 0 0
00 1 0 0 1
00 1 0 0 1
10 0 0 1 1
MOB MOA DSB
1
1
1
1
0
1
0
1
0
1
1
1
1
1
1
DSA
1
0
1
1
1
DRIVE
SELECTED
--
FDD A
FDD B
--
--
Table 7-3
DO REGISTER ( 3F2H )
Bit 7 Bit 6 Bit 5 Bit 4 Bit 1 Bit 0
00 0 0 x x
00 0 1 0 0
00 1 0 0 1
01 0 0 1 0
10 0 0 1 1
MOB MOA DSB
1
1
x
0
0
0
0
0
0
0
0
1
0
0
1
DSA
x
0
1
0
1
DRIVE
SELECTED
--
FDD A
FDD B
FDD C
FDD D
FIPURDWN (Bit 4):
This bit controls the internal pull-up resistors of the FDC input pins RDATA , INDEX , TRAK0,
DSKCHG, and WP.
0
The internal pull-up resistors of FDC are turned on.
1
The internal pull-up resistors of FDC are turned off.
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Publication ReleaseDate:Sep 1995
Revision A1