82371AB (PIIX4)
E
30
4/9/97 2:23 PM PIIX4aDS
INTEL CONFIDENTIAL
(until publication date)
PRELIMINARY
Name
Type
Description
PDIOR#
O
PRIMARY DISK IO READ.
In normal IDE this is the command to the IDE device that it
may drive data onto the PDD[15:0] lines. Data is latched by PIIX4 on the negation edge
of PDIOR#. The IDE device is selected either by the ATA register file chip selects
(PDCS1#, PDCS3#) and the PDA[2:0] lines, or the IDE DMA slave arbitration signals
(PDDACK#).
In an Ultra DMA/33 read cycle, this signal is used as DMARDY# which is negated by the
PIIX4 to pause Ultra DMA/33 transfers. In an Ultra DMA/33 write cycle, this signal is
used as the STROBE signal, with the drive latching data on rising and falling edges of
STROBE.
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.
During Reset:
High
After Reset:
High
During POS:
High
PDIOW#
O
PRIMARY DISK IO WRITE.
In normal IDE mode, this is the command to the IDE device
that it may latch data from the PDD[15:0] lines. Data is latched by the IDE device on the
negation edge of PDIOW#. The IDE device is selected either by the ATA register file
chip selects (PDCS1#, PDCS3#) and the PDA[2:0] lines, or the IDE DMA slave
arbitration signals (PDDACK#).
For Ultra DMA/33 mode, this signal is used as the STOP signal, which is used to
terminate an Ultra DMA/33 transaction. 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.
During Reset:
High
After Reset:
High
During POS:
High-Z
PIORDY
I
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.