11. Signals and Pinout
199
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
11.1.4
PCI-2 Signals
This section describes PowerSpan II signals used to interface to PCI-2. Signals in this group are
compatible with both 3V and 5V signaling environments
—
as defined by the
PCI 2.2 Specification
.
below summarizes the signals in this grouping. Signals with electrical characteristics different
from the remainder of the group are placed at the end of the table.
Ti
p
These signals are not implemented in the Single PCI PowerSpan II.
Table 57: PCI-2 Signals
a
Pin Name
Pin Type
Description
P2_AD[31:0]
Tristate bidirectional
PCI-2 Address/Data Bus:
Address and data are multiplexed over these pins
providing a 32-bit address/data bus.
P2_CBE[3:0]# Tristate
bidirectional
PCI-2 Bus Command and Byte Enable Lines:
Command and byte enable
information is multiplexed over all four CBE lines.
P2_DEVSEL#
Tristate bidirectional
PCI-2 Device Select:
An active low indication from an agent that is the target of
the current transaction. Driven by the target; sampled by the master. Rescinded
by the target at the end of the transaction.
P2_FRAME#
Tristate bidirectional
PCI-2 Cycle Frame for PCI Bus:
An active low indication from the current bus
master of the beginning and end of a transaction. Driven by the bus master,
sampled by the selected target. Rescinded by the bus master at the end of the
transaction.
P2_GNT[1]# Tristate
bidirectional
PCI-2 Grant:
This is an input when an external arbiter is used and an output
when the PCI-2 internal arbiter is used. As input it is used by the external arbiter
to grant the bus to PowerSpan II. As output it is used by the PCI-2 internal arbiter
to grant the bus to an external master.
This pin must be weakly pulled high in a system.
P2_GNT [4:2]#
Tristate output
PCI-2 Grant:
These are outputs only. They are used by the PCI-2 internal arbiter
to grant the bus to external masters.
These pins must be weakly pulled high in a system.
P2_IDSEL
Input
PCI-2 Initialization Device Select:
Used as a chip select during
Configuration
read and write transactions
P2_INTA#
Bidirectional open
drain
PCI -2 Interrupt A:
An active low level sensitive indication of an interrupt.
Asynchronous to P2_CLK
P2_IRDY#
Tristate bidirectional
PCI-2 Initiator Ready:
An active low indication of the current bus master’s ability
to complete the current dataphase. Driven by the master; sampled by the
selected target.
P2_PAR
Tristate bidirectional
PCI-2 Parity:
Carries even parity across P2_AD[31:0] and P2_C/BE[3:0]. Driven
by the master for the address and write dataphases. Driven by the target for read
dataphases.