Справочник Пользователя для AMD LX 900@1.5W
AMD Geode™ LX Processors Data Book
37
33234H
3.4.5
PCI Interface Signals
Signal Name
Ball No.
Type
f
V
Description
AD[31:0]
I/O
33-66 Mb/s
3.3
Multiplexed Address and Data. Addresses and
data are multiplexed together on the same pins.
A bus transaction consists of an address phase
in the cycle in which FRAME# is asserted fol-
lowed by one or more data phases. During the
address phase, AD[31:0] contain a physical 32-
bit address. During data phases, AD[7:0] contain
the least significant byte (LSB) and AD[31:24]
contain the most significant byte (MSB). Write
data is stable and valid when IRDY# is asserted
and read data is stable and valid when TRDY# is
asserted. Data is transferred during the SYSREF
when both IRDY# and TRDY# are asserted.
data are multiplexed together on the same pins.
A bus transaction consists of an address phase
in the cycle in which FRAME# is asserted fol-
lowed by one or more data phases. During the
address phase, AD[31:0] contain a physical 32-
bit address. During data phases, AD[7:0] contain
the least significant byte (LSB) and AD[31:24]
contain the most significant byte (MSB). Write
data is stable and valid when IRDY# is asserted
and read data is stable and valid when TRDY# is
asserted. Data is transferred during the SYSREF
when both IRDY# and TRDY# are asserted.
CBE[3:0]#
AH31,
AH27,
AH27,
AL26,
AJ22
I/O
33-66 Mb/s
3.3
Multiplexed Command and Byte Enables. C/
BE# are the bus commands and byte enables.
During the address phase of a transaction when
FRAME# is active, C/BE# define the bus com-
mand. During the data phase C/BE# are used as
byte enables. The byte enables are valid for the
entire data phase and determine which byte
lanes carry meaningful data. C/BE0# applies to
byte 0 (LSB) and C/BE3# applies to byte 3
(MSB). The command encoding and types are
listed below:
BE# are the bus commands and byte enables.
During the address phase of a transaction when
FRAME# is active, C/BE# define the bus com-
mand. During the data phase C/BE# are used as
byte enables. The byte enables are valid for the
entire data phase and determine which byte
lanes carry meaningful data. C/BE0# applies to
byte 0 (LSB) and C/BE3# applies to byte 3
(MSB). The command encoding and types are
listed below:
0000: Interrupt Acknowledge
0001: Special Cycle
0010: I/O Read
0011: I/O Write
0100: Reserved
0101: Reserved
0110: Memory Read
0111: Memory Write
1000: Reserved
1001: Reserved
1010: Configuration Read
1011: Configuration Write
1100: Memory Read Multiple
1101: Dual Address Cycle (RSVD)
1110: Memory Read Line
1111: Memory Write and Invalidate
0001: Special Cycle
0010: I/O Read
0011: I/O Write
0100: Reserved
0101: Reserved
0110: Memory Read
0111: Memory Write
1000: Reserved
1001: Reserved
1010: Configuration Read
1011: Configuration Write
1100: Memory Read Multiple
1101: Dual Address Cycle (RSVD)
1110: Memory Read Line
1111: Memory Write and Invalidate
PAR
AJ27
I/O
33-66 Mb/s
3.3
Parity. PAR is used with AD[31:0] and C/BE# to
generate even parity. Parity generation is
required by all PCI agents: the master drives PAR
for address and write-data phases and the target
drives PAR for read-data phases.
generate even parity. Parity generation is
required by all PCI agents: the master drives PAR
for address and write-data phases and the target
drives PAR for read-data phases.
For address phases, PAR is stable and valid one
SYSREF after the address phase.
SYSREF after the address phase.
For data phases, PAR is stable and valid one
SYSREF after either IRDY# is asserted on a
write transaction or after TRDY# is asserted on a
read transaction. Once PAR is valid, it remains
valid until one SYSREF after the completion of
the data phase.
SYSREF after either IRDY# is asserted on a
write transaction or after TRDY# is asserted on a
read transaction. Once PAR is valid, it remains
valid until one SYSREF after the completion of
the data phase.