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User’s Manual
32 ECB-870 User’s Manual
PDIORDY Primary IO Channel Ready. In normal IDE mode, this input signal is directly driven by the
corresponding IDE device IORDY signal. In an Ultra DMA/33 read cycle, this signal is used as
STROBE, with the PIIX4 latching
data on rising and falling edges of STROBE. In an Ultra DMA/33 write cycle, this signal is used
as the DMARDY# signal which is negated by the drive to pause Ultra DMA/33 transfers.
If the IDE signals are configured for Primary and Secondary, this signal is connected to the
corresponding signal on the Primary IDE connector.
If the IDE signals are configured for Primary Master and Primary Slave, this signal is used for
the Primary Master connector.
This is a Schmitt triggered input.
SDIORDY Secondary IO Channel Ready. In normal IDE mode, this input signal is directly driven by the
corresponding IDE device IORDY signal. In an Ultra DMA/33 read cycle, this signal is used as
STROBE, with the PIIX4 latching
data on rising and falling edges of STROBE. In an Ultra DMA write cycle, this signal is used as
the DMARDY# signal which is negated by the drive to pause Ultra DMA/33 transfers.
If the IDE signals are configured for Primary and Secondary, this signal is connected to the
corresponding signal on the Secondary IDE connector.
If the IDE signals are configured for Primary Master and Primary Slave, these signals are used
for the Primary Slave connector.
This is a Schmitt triggered input.
PDDREQ Primary Disk DMA Request. This input signal is directly driven from the IDE device DMARQ
signal. It is asserted by the IDE device to request a data transfer, and used in conjunction with
the PCI bus master IDE function. It is not associated with any AT compatible DMA channel.
If the IDE signals are configured for Primary and Secondary, this signal is connected to the
corresponding signal on the Primary IDE connector.
If the IDE signals are configured for Primary Master and Primary Slave, this signal is used for
the Primary Master connector.
SDDREQ Secondary Disk DMA Request. This input signal is directly driven from the IDE device
DMARQ signal. It is asserted by the IDE device to request a data transfer, and used in
conjunction with the PCI bus master IDE function. It is not associated with any AT compatible
DMA channel.
If the IDE signals are configured for Primary and Secondary, this signal is connected to the
corresponding signal on the Secondary IDE connector.
If the IDE signals are configured for Primary Master and Primary Slave, these signals are used
for the Primary Slave connector.
PDDACK# Primary DMA Acknowledge. This signal directly drives the IDE device DMACK# signal. It is
asserted by PIIX4 to indicate to IDE DMA slave devices that a given data transfer cycle
(assertion of PDIOR# or PDIOW#) is a DMA data transfer cycle. This signal is used in
conjunction with the PCI bus master IDE function. It is not associated with any AT compatible
DMA channel. If the IDE signals are configured for Primary and Secondary, this signal is
connected to the corresponding signal on the Primary IDE connector. If the IDE signals are
configured for Primary Master and Primary Slave, this signal is used for the Primary Master
connector.