
W83877AF
Publication Release Date: Dec. 1996
Preliminary Version 0.52
- 17 -
1.5 IDE and FDC Interface
SYMBOL
PIN
1
I/O
FUNCTION
RESIDE
IRQ_G
DRQ_D
IRSL2
OUT
12t
OUT
12t
OUT
12t
OUT
12t
OUT
12t
OUT
12t
OUT
12t
When CR16 Bit 1 (IRIDE) = 0: Active low reset signal for IDE;
When CR16 Bit 1 (IRIDE) = 1: Interrupt request signal G.
DMA request signal.
IR module mode select 2.
When CR16 Bit 1 (IRIDE) = 0: Active low enable signal for IDE;
When CR16 Bit 1 (IRIDE) = 1: Interrupt request signal H.
IR module mode selection 2.
IDBEN
IRQ_H
IRSL2
DACK_N
IRRXH/IRSL0
91
IN
t
I/O
12t
DMA acknowledge signal D.
When input selected, act as high speed IR receiving terminal.
When output selected, act as IR module mode selection 0.
When CR16 Bit 1 (IRIDE) = 0: This pin is used to select the IDE
controller.
CS1
decodes the HDC addresses specified in
CR22.
When CR16 Bit 1 (IRIDE) = 1: Function as a InfraRed
transmission data line.
When CR16 Bit 1 (IRIDE) = 0: This pin is used to select the IDE
controller. CS0 decodes HDC addresses specified in CR21.
When CR16 Bit 1 (IRIDE) = 1: Function as a InfraRed receiving
line.
Write enable. An open drain output.
Direction of the head step motor. An open drain output.
Logic 1 = outward motion
Logic 0 = inward motion
Head select. This open drain output determines which disk drive
head is active.
Logic 1 = side 0
Logic 0 = side 1
Reduced write current. This signal can be used on two-speed
disk drives to select the transfer rate. An open drain output.
Logic 0 = 250 Kb/s
Logic 1 = 500 Kb/s
When bit 5 of CR9 (EN3MODE) is set to high, the three-mode
FDD function is enabled, and the pin will have a different
definition. Refer to the EN3MODE bit in CR9.
Write data. This logic low open drain writes precompensation
serial data to the selected FDD. An open drain output.
CS1
IRTX2
95
OUT
12t
OUT
12t
CS0
IRRX2
94
OUT
12t
IN
t
WE
DIR
85
89
OD
24
OD
24
HEAD
88
OD
24
RWC
87
OD
24
WD
86
OD
24