82091AA Datasheet, PDF (15/204 Pages) Intel Corporation – ADVANCED INTEGRATED PERIPHERAL (AIP)

82091AA
2 1 Host Interface Signals (Continued)
Signal
Name
Type
Description
INTERRUPT SIGNALS (Continued)
IRQ6
O INTERRUPT REQUEST 6 IRQ6 is associated with the floppy disk controller and can
be programmed (via the AIPCFG2 Register) to be either active high or active low In
non-DMA mode this signal is asserted to signal when a data transfer is ready IRQ6 is
also asserted to signal the completion of the execution phase for certain FDC
commands This signal is enabled disabled by the DMAGATE bit in the Digital Output
Register of the FDC The signal is tri-stated when disabled
2 2 Floppy Disk Controller Interface
Signal
Name
Type
Description
RDDATA
I
READ DATA Serial data from the disk drive
WRDATA
O WRITE DATA MFM serial data to the disk drive Precompensation value is
selectable through software
HDSEL
O HEAD SELECT Selects which side of a disk is to be accessed When asserted
(low) side 1 is selected When negated (high) side 0 is selected
STEP
O STEP STEP supplies step pulses (asserted) to the drive to move the head
between the tracks during a seek operation
DIR
O DIRECTION Controls the direction the head moves when a step signal is present
The head moves toward the center when DIR is asserted and away from the
center when negated
WE
O WRITE ENABLE WE is a disk drive control signal When asserted WE
enables the head to write to the disk
TRK0
I
TRACK0 The disk drive asserts this signal to indicate that the head is on track 0
INDX
I
INDEX The disk drive asserts this signal to indicate the beginning of the track
WP
I
WRITE PROTECT The disk drive asserts this signal to indicate that the disk drive
is write-protected
DSKCHG
I
DISK CHANGE The disk drive asserts this signal to indicate that the drive door
has been opened The state of this signal input is available in the Digital Input
Register (DIR )
DRIVDEN0
O
DRIVE DENSITY These signals are used by the disk drive to configure the drive
DRIVDEN1
for the appropriate media density These signals are controlled by the FDC’s Drive
Specification Command
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