82551IT Datasheet, PDF (34/102 Pages) Intel Corporation – Fast Ethernet PCI Controller

82551IT — Networking Silicon
If PME# is enabled (in the PCI power management registers), the RST# signal does not affect any
PME# related circuits (in other words, the PCI power management registers, and the wake-up
packet would not be affected).
Note: The PCI Specification, Revision 2.2, states that the PCI RST# signal should be active low in the B3
state. (In PCI Specification, Revision 2.1, the PCI RST# signal is undefined during the B3 state.)
The transition from the B3 bus power state to the B0 bus power state occurs on the trailing edge of
the PCI RST# signal.
The initialization signal is generated internally in the following cases:
• Active RST# signal while the 82551IT is the D0, D1, or D2 power state
• RST# trailing edge while the 82551IT is in the D3 power state
• ISOLATE# trailing edge
The internal initialization signal resets the PCI Configuration Space, MAC configuration, and
memory structure.
The behavior of the RST# and ISOLATE# pins and the internal 82551IT initialization signal are
shown in the following figure.
Figure 9. Initialization upon RST# and ISOLATE#
RST#
Internal hardware
reset
D0 - D2 power state
RST#
Internal hardware
reset
ISOLATE#
Internal hardware
reset
D3 power state
640 ns
Internal reset
due to ISOLATE#
640 ns
28
Datasheet