RTL8208

2001/01/07

28

Rev.1.923

7.7 Power Saving and Power Down Mode

7.7.1 Power Saving Mode

The RTL8208 implements a power saving mode on a per port basis. One port automatically enters power saving mode 10

seconds after the cable is disconnected from it, regardless of whether the RTL8208’s operation mode is Nway or Force mode.

Once one port enters power saving mode, it transmits normal link pulses only on its TXOP/TXON pins and keeps monitoring

RXIP/RXIN to try to detect any incoming signals , which might be 100Base-TX MLT-3 idle pattern, 10Base-T link pulses or

Nway’s FLP (fast link pulses). After it detects any incoming signals, it wakes up from the power saving mode and operates in the

normal mode according to the result of the connection.

Power saving mode is not supported when in 100FX operation.

7.7.2 Power Down Mode

Setting Register 0.11through the SMI interface forces the corresponding port of the RTL8208 to enter power down mode, which

disables all transmit/receive functions and RMII functions on that port, except SMI (MDC/MDIO management interface).

7.8 LED Configuration

The RTL8208 supports serial LED status streams for LED display. The forms of LED status streams, as shown below, are

controlled by LEDMODE[1:0] pins, which are latched upon reset. All LED statuses are represented as active-low, except

Link/Act in Bi-color LED mode, whose polarity depends on Spd status.

LEDMODE[1:0]

Mode

Output sequences

00

3-bit serial stream

Col/Fulldup, Link/Act, Spd

01

2-bit serial stream

Spd,

Link/Act

10

3-bit for Bi-color LED Col/Fulldup, Link/Act, Spd

LED Statuses

Description

Col/Fulldup

Col, Full duplex Indicator. Blinking every 43ms when collision

happens. Low for full duplex, and high for half duplex mode.

Link/Act

Link, Activity Indicator. For 3-bit serial stream mode, low for link

established. For 3-bit Bi-color LED mode, Link/Act is high for link

established when speed is low (100Mb/s); Link/Act is low for link

established when speed is high (10Mb/s). Link/Act Blinks every

43ms when the corresponding port is transmitting or receiving.

Spd

Speed Indicator. Low for 100Mb/s, and high for 10Mb/s.

7.8.1 LED Blinking Time

LED blinking time can be set to 120ms by setting LED_BLNK_TIME=0. The LED statuses supporting 43/120ms blinking time

are Col/Fulldup, Link/Act. For status Link/Act/Spd, the LED blinking time is not affected by LED_BLNK_TIME.