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Nm9715
PCI Dual 1284 Printer Ports
Rev. 1.2
Pin Name
128
Type
Description
nRESET
121
I
PCI system reset (active low). Resets all internal register, sequencers, and
signals to a consistent state. During reset condition, AD31-0 and nSER are
three-stated.
AD31-29 126-128
I/O
Multiplexed PCI address/data bus. A bus transaction consists of an address
phase followed by one or more data phases. During the address phase AD31-
0 contain a physical address. Write data is stable and valid when nIRDY and
nTRDY are asserted (active).
AD28-24
2-6
I/O
See AD31-29 description.
AD23-16
11-18
I/O
See AD31-29 description.
AD15-11
34-38
I/O
See AD31-29 description.
AD10-8
40-42
I/O
See AD31-29 description.
AD7-0
46-53
I/O
See AD31-29 description.
nFRAME
23
I
Frame is driven by the current master to indicate the beginning and duration
of an access. nFRAME is asserted to indicate a bus transaction is beginning.
While nFRAME is active, data transfer continues.
nIRDY
24
I
Initiator Ready. During a write, nIRDY asserted indicates that the initiator is
driving valid data onto the data bus. During a read, nIRDY asserted indicates
that the initiator is ready to accept data from the Nm9715.
nTRDY
25
O
Target Ready (three-state). It is asserted when Nm9715 is ready to complete
the current data phase.
nSTOP
27
O
Nm9715 asserts nSTOP to indicate that it wishes the initiator to stop the
transaction in process on the current data phase.
nLOCK
28
I
Lock indicates an atomic operation that may require multiple transactions to
complete.
IDSEL
9
I
Initialization Device Select. It is used as a chip select during configuration
read and write transactions.
nDEVSEL
26
O
Device Select (three-state). Nm9715 asserts nDEVSEL when the Nm9715
has decoded its address.
nPERR
29
O
Parity Error (three-state). Is used to report parity errors during all PCI trans-
actions except a special cycle. The minimum duration of nPERR is one clock
cycle.