LAN9730 Datasheet, PDF (110/222 Pages) SMSC Corporation – High-Speed Inter-Chip (HSIC) USB 2.0

LAN9730/LAN9730i
4.12.2.2 Enabling WOL Wake Events
The host system must perform the following steps to enable the device to assert a remote_wake event on detection of
a Wake on LAN event.
1. All transmit and receive operations must be halted:
a) All pending Ethernet TX and RX operations must be completed.
b) The MAC must be halted.
2. The MAC must be configured to detect the desired wake event. This process is explained in Section 4.5.5,
"Wakeup Frame Detection" for Wakeup Frames and in Section 4.5.6, "Magic Packet Detection" for Magic Pack-
ets.
Configuring Perfect DA and Broadcast Frame wakeup detection is analogous and requires the Perfect DA
Wakeup Enable (PFDA_EN) or Broadcast Wakeup Enable (BCAST_EN) bit to be set in the Wakeup Control and
Status Register (WUCSR).
3. Bit 1 of the Wakeup Status (WUPS[1]) in the Power Management Control Register (PMT_CTL) must be cleared
since a set bit will cause the immediate assertion of wake event when the Wake On LAN Enable (WOL_EN) bit
is set. The WUPS[1] bit will not clear if the internal MAC wakeup event is asserted.
4. Set the Wake On LAN Enable (WOL_EN) bit in the Power Management Control Register (PMT_CTL).
5. The host places the device in the SUSPEND0 state by setting the Suspend Mode (SUSPEND_MODE) field in
the Power Management Control Register (PMT_CTL) to 00b, to indicate the desired SUSPEND state, then sends
suspend signaling.
On detection of an enabled event, the device will transition back to the NORMAL state and signal a remote_wake event.
The software will then examine the Suspend Mode (SUSPEND_MODE) field of the Power Management Control Reg-
ister (PMT_CTL). Upon discovering wakeup occurred from SUSPEND0 state, the status bits of the WUCSR register
may be examined to determine the particular event that caused the wakeup.
4.12.2.3 Enabling Link Status Change (Energy Detect) Wake Events
The host system must perform the following steps to enable the device to assert a remote_wake event on detection of
an Ethernet link status change.
1. All transmit and receive operations must be halted:
a) All pending Ethernet TX and RX operations must be completed.
b) The MAC must be halted.
2. The PHY must be enabled for the Energy Detect Power-Down mode This is done by clearing the EDPWRDOWN
bit in the PHY’s Mode Control/Status Register. Enabling the Energy Detect Power-Down mode places the PHY
in a reduced power state. In this mode of operation the PHY is not capable of receiving or transmitting Ethernet
data. In this state, the PHY will assert its internal interrupt if it detects Ethernet activity. Refer to Section 4.6.8.2,
"Energy Detect Power-Down (EDPD)" for more information.
3. Bit 0 of the Wakeup Status (WUPS[0]) in the Power Management Control Register (PMT_CTL) must be cleared,
since a set bit will cause the immediate assertion of wake event when Energy-Detect Enable (ED_EN) is set. The
WUPS[0] bit will not clear if the internal PHY interrupt is asserted.
4. Set the Energy-Detect Enable (ED_EN) bit in the Power Management Control Register (PMT_CTL).
5. The host places the device in the SUSPEND1 state by setting the Suspend Mode (SUSPEND_MODE) field in
the Power Management Control Register (PMT_CTL) to 01b, to indicate the desired SUSPEND state, then sends
suspend signaling.
On detection of Ethernet activity (energy), the device will transition back to the NORMAL state and signal a
remote_wake event.
DS00001946A-page 110
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