Wake on LAN Mode/Low-Power
BCM5718 Programmer’s Guide
Broadcom
®
January 29, 2016 • 5718-PG108-R
Page 213
Functional Overview
The Ethernet controller is capable of WOL in 10/100 Mbps for copper-based controllers.
The Ethernet controller uses the TX FIFO to store pattern data (see
). During WOL operation, the
transmit engine is disabled and its FIFO is free for use. The TDE fetches data from the memory arbiter starting
at a location specified in the WOL_Pattern_Pointer register. The WOL pattern checker pulls data off the TX FIFO
for packet comparisons. The RX MAC will move incoming frame(s) to the pattern checker, and the remaining
RX data path is not utilized. A state machine controls the Magic Packet comparisons. The WOL state machine
will move out of an Idle state, when ACPI power management is enabled. The WOL state machine will clear the
TX FIFO and Match register. The Match register indicates a positive Magic Packet comparison(s) on a stream.
In 10/100 Mbit mode, data is received once every four clock cycles. The pattern checker compares the first three
patterns in the first cycle, the second three patterns in the second cycle, and the third three patterns in the last
cycle. It is idle during the fourth cycle. In Gigabit mode, the pattern checker gets three pattern words from the
FIFO at one time.
Figure 46: WOL Functional Block Diagram
Note:
When configured for WOL in 1000 Mbps mode, the Ethernet controller draws more than the 375
mA allowed by the PCI specification.
Rx MAC
Pattern
Checker
Tx FIFO
TDE
Memory
Arbiter
Internal
Memory
Pattern
Data
RX
PCS
RX
RMII
RX
GMII
RX
IO
Power
Managment