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CHAPTER 2 PIN FUNCTIONS
37
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PCI bus 64-bit expansion interface signals
When a 32-bit PCI bus interface signal is used, leave the AD63-AD32, PCBE7_B-PCBE4_B, and
PAR64 signals open.
Symbol
Pin No.
I/O
I/O level
Function
AD63-AD32
69 - 71, 73 - 75,
79, 80, 82 - 85,
88 - 91, 94 - 97,
100 - 103,
106 - 109,
112 - 115
I/O
3-state
PCI
Address/Data
AD63 to AD32 constitute a 32-bit multiplexed
address/data bus for PCI bus 64-bit expansion. During
address phases, AD63 to AD32 carry the 32 high-order
bits of a 64-bit address. During data phases, when both
REQ64_B and ACK64_B are asserted, AD64 to AD32
carry the data of the 32 high-order bits for 64-bit data
transfer.
PCBE7_B
PCBE6_B
PCBE5_B
PCBE4_B
63
64
65
66
I/O
3-state
PCI
Bus Command/Byte Enable
During address phases, the PCBE7_B to PCBE4_B
signals define a bus command (bus transaction to be
generated). During data phases, these signals indicate
whether their corresponding byte lanes hold valid data.
The PCBE7_B pin corresponds to AD63 to AD56; the
PCBE4_B pin to AD39 to AD32.
PAR64
116
I/O
3-state
PCI
Parity 64
The PAR64 signal indicates the even parity across
AD63 to AD32 and PCBE7_B to PCBE4_B including
the PAR64 signal. When the
μ
PD98405 is operating as
the master, the PAR signal is activated during the
address and write data phases. When the
μ
PD98405
operates as the target, the signal is activated during
read data phases.
REQ64_B
60
I/O
3-state
PCI
Request 64
The REQ64_B signal indicates the start and period of a
64-bit bus transaction. When the
μ
PD98405 operates
as the master, it activates REQ64_B to request 64-bit
data transfer. The timing of REQ64_B is the same as
that of FRAME_B.
ACK64_B
59
I/O
Sustained
3-state
PCI
Acknowledge 64
When the
μ
PD98405 operates as the target and
recognizes an address after the REQ64_B signal has
been activated, it drives the ACK64_B signal low.
When the
μ
PD98405 operates as the master, it samples
the ACK64_B signal to check that the target device
responds to the 64-bit transfer request. The timing of
ACK64_B is the same as that of DEVSEL_B.