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3.
Signal Descriptions
3.1
Signal Type Definitions
Type
IN
OUT
T/S
S/T/S
O/D
A/I
A/O
B
3.2
PCI Bus Interface Signals
3.2.1
Address and Data Signals
Symbol
AD[31:0]
C/BE[3:0]#
PAR
Datasheet
Name
Input
The input pin is a standard input only signal.
The output pin is a Totem Pole Output pin and is a standard
Output
active driver.
Tri-State
The tri-state pin is a bidirectional, input/output pin.
The sustained tri-state pin is an active low tri-state signal owned
and driven by one agent at a time. The agent asserting the S/T/
S pin low must drive it high at least one clock cycle before
Sustained Tri-State
floating the pin. A new agent can only assert an S/T/S signal low
one clock cycle after it has been tri-stated by the previous
owner.
The open drain pin allows multiple devices to share this signal
Open Drain
as a wired-OR.
Analog Input
The analog input pin is used for analog input signals.
Analog Output
The analog output pin is used for analog output signals.
Bias
The bias pin is an input bias.
Type
Address and Data. The address and data lines are multiplexed on
the same PCI pins. A bus transaction consists of an address phase
followed by one or more data phases. During the address phase, the
address and data lines contain the 32-bit physical address. For I/O,
T/S
this is a byte address; for configuration and memory, it is a Dword
address. The 82559ER uses little-endian byte ordering (in other
words, AD[31:24] contain the most significant byte and AD[7:0]
contain the least significant byte). During the data phases, the address
and data lines contain data.
Command and Byte Enable. The bus command and byte enable
signals are multiplexed on the same PCI pins. During the address
phase, the C/BE# lines define the bus command. During the data
T/S
phase, the C/BE# lines are used as Byte Enables. The Byte Enables
are valid for the entire data phase and determine which byte lanes
carry meaningful data.
Parity. Parity is even across AD[31:0] and C/BE[3:0]# lines. It is stable
and valid one clock after the address phase. For data phases, PAR is
stable and valid one clock after either IRDY# is asserted on a write
T/S
transaction or TRDY# is asserted on a read transaction.Once PAR is
valid, it remains valid until one clock after the completion of the current
data phase. The master drives PAR for address and write data
phases; and the target, for read data phases.
Networking Silicon —GD82559ER
Description
Name and Function
7
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