LAN9218I-MT-E2 View Datasheet(PDF) - SMSC -> Microchip

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LAN9218I-MT-E2

High-Performance Single Chip 10/100 Ethernet Controller with HP Auto-MDIX & Industrial Temperature Support

SMSC -> Microchip 

3.11

3.11.1

3.11.2

3.11.2.1

High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX & Industrial Temperature Support

Datasheet

Power Management

The LAN9218I supports power-down modes to allow applications to minimize power consumption. The

following sections describe these modes.

System Description

Power is reduced to various modules by disabling the clocks as outlined in Table 3.9, “Power

Management States,” on page 37. All configuration data is saved when in either of the twolow power

states. Register contents are not affected unless specifically indicated in the register description.

Functional Description

There is one normal operating power state, D0 and there are two power saving states: D1, and D2.

Upon entry into either of the two power saving states, only the PMT_CTRL register is accessible for

read operations. In either of the power saving states the READY bit in the PMT_CTRL register will be

cleared. Reads of any other addresses are forbidden until the READY bit is set. All writes, with the

exception of the wakeup write to BYTE_TEST, are also forbidden until the READY bit is set. Only when

in the D0 (Normal) state, when the READY bit is set, can the rest of the device be accessed.

Note 3.3 The LAN9218I must always be read at least once after power-up, reset, or upon return

from a power-saving state, otherwise write operations will not function.

In system configurations where the PME signal is shared amongst multiple devices, the WUPS field

within the PMT_CTRL register can be read to determine which LAN9218I device is driving the PME

signal.

When the LAN9218I is in a power saving state (D1 or D2), a write cycle to the BYTE_TEST register

will return the LAN9218I to the D0 state. Table 7.2, “Power Consumption Device and System

Components,” on page 126 and Table 7.2, “Power Consumption Device and System Components,” on

page 126, shows the power consumption values for each power state.

Note 3.4

When the LAN9218I is in a power saving state, a write of any data to the BYTE_TEST

register will wake-up the device. DO NOT PERFORM WRITES TO OTHER

ADDRRESSES while the READY bit in the PMT_CTRL register is cleared.

D1 Sleep

Power consumption is reduced in this state by disabling clocks to portions of the internal logic as

shown in Table 3.9. In this mode the clock to the internal PHY and portions of the MAC are still

operational. This state is entered when the host writes a '01' to the PM_MODE bits in the Power

Management (PMT_CTRL) register. The READY bit in PMT_CTRL is cleared when entering the D1

state.

Wake-up frame and Magic Packet detection are automatically enabled in the D1 state. If properly

enabled via the WOL_EN and PME_EN bits, the LAN9218I will assert the PME hardware signal upon

the detection of the wake-up frame or magic packet. The LAN9218I can also assert the host interrupt

(IRQ) on detection of a wake-up frame or magic packet. Upon detection, the WUPS field in PMT_CTRL

will be set to a 10b.

Note 3.5 The PME interrupt status bit (PME_INT) in the INT_STS register is set regardless of the

setting of PME_EN.

Note 3.6

Wake-up frame and Magic Packet detection is automatically enabled when entering the D1

state. For wake-up frame detection, the wake-up frame filter must be programmed before

entering the D1 state (see Section 3.5, "Wake-up Frame Detection," on page 25). If used,

the host interrupt and PME signal must be enabled prior to entering the D1 state.

A write to the BYTE_TEST register, regardless of whether a wake-up frame or Magic Packet was

detected, will return LAN9218I to the D0 state and will reset the PM_MODE field to the D0 state. As

Revision 1.5 (07-18-06)

36

DATASHEET

SMSC LAN9218I

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