RTL8208B-LF/RTL8208BF-LF
Datasheet
7.2. Initialization and Setup
7.2.1. Reset
The RTL8208B(F)-LF is initialized while in the reset state. During reset, each transceiver is reset
simultaneously. There are three ways to reset the RTL8208B(F)-LF: Power-on auto reset; hardware pin
reset; and software reset. The internal power-on auto-reset circuit can reset the chip while the reset pin is
floating. The hardware reset signal must be asserted low for at least 10ms on the RESET# pin. A software
reset is implemented by writing Register 0.15=1, which is self-clearing.
7.2.2. Setup and Configuration
The operational modes of the RTL8208B(F)-LF can be configured either by hardware pin (pulled high or
low) upon reset, or by software programming via accessing the RTL8208B(F)-LF registers through the
SMI (see section 5 Pin Descriptions, page 6 for details).
7.3. 10Base-T
7.3.1. Transmit Function
When TX_EN is active, TXD from RMII/SMII/SS-SMII is serialized, Manchester-encoded, and driven
onto the network medium as a packet stream. An on-chip filtering and wave shaping circuit eliminates the
need for external filtering. The transmit function is disabled when the link has failed or when the auto-
negotiation process is in progress.
7.3.2. Receive Function
The Manchester decoder converts the incoming serial stream when the circuit detects the signal, and the
digital serial stream is then converted to 2-bit (RMII) or 1-bit (SMII/SS-SMII) data format. The preamble
of the incoming stream is stripped off and regenerated. SFD is generated into RXD once the incoming
SFD is detected and data bits entering the elastic buffer are over threshold.
7.3.3. Link Monitor
The 10Base-T link pulse detection circuit continually monitors the RXIP/RXIN pins for the presence of
valid link pulses. Auto-polarity is implemented to correct the detected reverse polarity of RXIP/RXIN
signal pairs.
The 10Base-T link pulse detection circuit constantly monitors the RXIP/RXIN pins for the presence of
valid link pulses. Auto-polarity is implemented for correcting the detected reverse polarity of the
RXIP/RXIN signal pairs.
Single-Chip Octal 10/100-TX/FX PHY Transceiver
28
Track ID: JATR-1076-21 Rev. 1.3
REALTEK [ Realtek Semiconductor Corp. ]
