82801DB Datasheet, PDF (43/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

Signal Description
2.6
IDE Interface
Table 2-6. IDE Interface Signals
Name
PDCS1#,
SDCS1#
PDCS3#,
SDCS3#
PDA[2:0],
SDA[2:0]
PDD[15:0],
SDD[15:0]
PDDREQ,
SDDREQ
PDDACK#,
SDDACK#
PDIOR# /
(PDWSTB /
PRDMARDY#)
SDIOR# /
(SDWSTB /
SRDMARDY#)
PDIOW# /
(PDSTOP)
SDIOW# /
(SDSTOP)
PIORDY /
(PDRSTB /
PWDMARDY#)
SIORDY /
(SDRSTB /
SWDMARDY#)
Type
O
O
O
I/O
I
O
O
O
I
Description
Primary and Secondary IDE Device Chip Selects for 100 Range: For ATA
command register block. This output signal is connected to the corresponding
signal on the primary or secondary IDE connector.
Primary and Secondary IDE Device Chip Select for 300 Range: For ATA
control register block. This output signal is connected to the corresponding
signal on the primary or secondary IDE connector.
Primary and Secondary IDE Device Address: These output signals are
connected to the corresponding signals on the primary or secondary IDE
connectors. They are used to indicate which byte in either the ATA command
block or control block is being addressed.
Primary and Secondary IDE Device Data: These signals directly drive the
corresponding signals on the primary or secondary IDE connector. There is a
weak internal pull-down resistor on PDD[7] and SDD[7].
Primary and Secondary IDE Device DMA Request: These input signals are
directly driven from the DRQ signals on the primary or secondary IDE
connector. It is asserted by the IDE device to request a data transfer, and used
in conjunction with the PCI bus master IDE function and are not associated with
any AT compatible DMA channel. There is a weak internal pull-down resistor on
these signals.
Primary and Secondary IDE Device DMA Acknowledge: These signals
directly drive the DAK# signals on the primary and secondary IDE connectors.
Each is asserted by the Intel^® ICH4 to indicate to IDE DMA slave devices that a
given data transfer cycle (assertion of DIOR# or DIOW#) is a DMA data transfer
cycle. This signal is used in conjunction with the PCI bus master IDE function
and are not associated with any AT-compatible DMA channel.
Primary and Secondary Disk I/O Read (PIO and Non-Ultra DMA): This is the
command to the IDE device that it may drive data onto the PDD or SDD lines.
Data is latched by the ICH4 on the deassertion edge of PDIOR# or SDIOR#.
The IDE device is selected either by the ATA register file chip selects (PDCS1#
or SDCS1#, PDCS3# or SDCS3#) and the PDA or SDA lines, or the IDE DMA
acknowledge (PDDAK# or SDDAK#).
Primary and Secondary Disk Write Strobe (Ultra DMA Writes to Disk): This is
the data write strobe for writes to disk. When writing to disk, ICH4 drives valid
data on rising and falling edges of PDWSTB or SDWSTB.
Primary and Secondary Disk DMA Ready (Ultra DMA Reads from Disk): This is
the DMA ready for reads from disk. When reading from disk, ICH4 deasserts
PRDMARDY# or SRDMARDY# to pause burst data transfers.
Primary and Secondary Disk I/O Write (PIO and Non-Ultra DMA): This is the
command to the IDE device that it may latch data from the PDD or SDD lines.
Data is latched by the IDE device on the deassertion edge of PDIOW# or
SDIOW#. The IDE device is selected either by the ATA register file chip selects
(PDCS1# or SDCS1#, PDCS3# or SDCS3#) and the PDA or SDA lines, or the
IDE DMA acknowledge (PDDAK# or SDDAK#).
Primary and Secondary Disk Stop (Ultra DMA): ICH4 asserts this signal to
terminate a burst.
Primary and Secondary I/O Channel Ready (PIO): This signal will keep the
strobe active (PDIOR# or SDIOR# on reads, PDIOW# or SDIOW# on writes)
longer than the minimum width. It adds wait states to PIO transfers.
Primary and Secondary Disk Read Strobe (Ultra DMA Reads from Disk): When
reading from disk, ICH4 latches data on rising and falling edges of this signal
from the disk.
Primary and Secondary Disk DMA Ready (Ultra DMA Writes to Disk): When
writing to disk, this is de-asserted by the disk to pause burst data transfers.
Intel^® 82801DB ICH4 Datasheet
43