RTL8306SD/RTL8306SDM
Datasheet
7.2.
Physical Layer Functional Overview
7.2.1.
Auto-Negotiation for UTP
The RTL8306SD/RTL8306SDM obtains the states of duplex, speed, and flow control ability for each port
in UTP mode through the auto-negotiation mechanism defined in the IEEE 802.3u specifications. During
auto-negotiation, each port advertises its ability to its link partner and compares its ability with
advertisements received from its link partner. By default, the RTL8306SD/RTL8306SDM advertises full
capabilities (100Full, 100Half, 10Full, 10Half) together with flow control ability.
7.2.2.
10Base-T Transmit Function
The output 10Base-T waveform is Manchester-encoded before it is driven onto the network media. The
internal filter shapes the driven signals to reduce EMI emissions, eliminating the need for an external
filter.
7.2.3.
10Base-T Receive Function
The Manchester decoder converts the incoming serial stream to NRZ data when the squelch circuit
detects the signal level is above squelch level.
7.2.4.
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.
7.2.5.
100Base-TX Transmit Function
The 100Base-TX transmit function performs parallel to serial conversion, 4B/5B coding, scrambling,
NRZ/NRZI conversion, and MLT-3 encoding. The 5-bit serial data stream after 4B/5B coding is then
scrambled as defined by the TP-PMD Stream Cipher function to flatten the power spectrum energy such
that EMI effects are significantly reduced.
The scrambled seed is based on PHY addresses and is unique for each port. After scrambling, the bit
stream is driven into the network media in the form of MLT-3 signaling. The MLT-3 multi-level
signaling technology moves the power spectrum energy from high frequency to low frequency, which
further reduces EMI emissions.
6-Port 10/100Mbps Single-Chip Dual MII/RMII Switch Controller
39
Track ID: JATR-1076-21 Rev. 1.1
REALTEK [ Realtek Semiconductor Corp. ]
