W83877 Winbond Electronics Corp America, W83877 Datasheet - Page 18

• Manufacturer Part Number: W83877
• Description: Winbond I/O
• Manufacturer: Winbond Electronics Corp America

1.5 IDE and FDC Interface, continued
2.0 FDC FUNCTIONAL DESCRIPTION
2.1 W83877F FDC
The floppy disk controller of the W83877F integrates all of the logic required for floppy disk control.
The FDC implements a PC/AT or PS/2 solution. All programmable options default to compatible
values. The FIFO provides better system performance in multi-master systems. The digital data
separator supports up to 1 M bits/sec data rate.
The FDC includes the following blocks: AT interface, Precompensation, Data Rate Selection, Digital
Data Separator, FIFO, and FDC Core.
V
GND
TRAK0
RDATA
DSKCHG
MOA
MOB
DSA
DSB
WP
DD
SYMBOL
PIN
15,
25,
65,
78
77
74
76
79
80
83
84
56
40
90
OD
OD
OD
OD
IN
IN
IN
IN
I/O
cs
cs
cs
cs
24
24
24
24
Track 0. This schmitt input from the disk drive is active low when
the head is positioned over the outermost track. This input pin is
pulled up internally by an approximately 1K ohm resistor. The
resistor can be disabled by bit 4 of CR6 (FIPURDWN).
Write protected. This active low schmitt input from the disk drive
indicates that the diskette is write-protected. This input pin is
pulled up internally by an approximately 1K ohm resistor. The
resistor can be disabled by bit 4 of CR6 (FIPURDWN).
The read data input signal from the FDD. This input pin is pulled
up internally by an approximately 1K ohm resistor. The resistor
can be disabled by bit 4 of CR6 (FIPURDWN).
Diskette change. This signal is active low at power on and
whenever the diskette is removed. This input pin is pulled up
internally by an approximately 1K ohm resistor. The resistor can
be disabled by bit 4 of CR6 (FIPURDWN).
Motor A On. When set to 0, this pin enables disk drive 0. This is
an open drain output.
Motor B On. When set to 0, this pin enables disk drive 1. This is
an open drain output.
Drive Select A. When set to 0, this pin enables disk drive A. This
is an open drain output.
Drive Select B. When set to 0, this pin enables disk drive B. This
is an open drain output.
+5 power supply for the digital circuitry
Ground
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FUNCTION
W83877F