STEVAL-PCC010V1 STMicroelectronics, STEVAL-PCC010V1 Datasheet - Page 38

• Manufacturer Part Number: STEVAL-PCC010V1
• Description: BOARD EVAL FOR ST802RT1
• Manufacturer: STMicroelectronics

Specifications of STEVAL-PCC010V1

• Main Purpose: Interface, Ethernet Controller (PHY and MAC)
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ST802RT1
• Primary Attributes: 1 Port, 100BASE-TX/10BASE-T
• Secondary Attributes: MII, RMII
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-10360

Device operation
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Device operation
The ST802RT1x includes a 10/100 Base-T Ethernet transceiver with MII, RMII interfaces for
data and control from/to the station management entity (STE). The ST802RT1x integrates
the IEEE802.3u compliant functions of PCS (physical coding sub-layer), PMA (physical
medium attachment), and PMD (physical medium dependent) for 100Base-TX, and the
IEEE802.3 compliant functions of manchester encoding/decoding and transceiver for
10Base-T. IEEE standard auto-negotiation functions are also supported. Media independent
interface (MII) is a 4-bit interface transferring 10 Mbit data using a 2.5 MHz clock and 100
Mbit data using a 25 MHz clock. RMII (reduced media independent interface) is a low pin
count alternative capable of transferring 10 and 100 Mbit dibits data using a 50 MHz
reference clock. All the functions and operation schemes are described in the sections that
follow.
100Base-TX transmit operation
In 100Base-TX transmission, the device provides the transmission functions of PCS, PMA,
and PMD for encoding of MII data nibbles to five-bit code-groups (4B/5B), scrambling,
serialization of scrambled code-groups, converting the serial NRZ code into NRZI code,
converting the NRZI code into MLT3 code, and then driving the MLT3 code into the category
5 unshielded twisted pair cable through an isolation transformer with a turn ratio of 1.414:1.
Data code-groups encoder: In normal MII mode application, the device receives nibble type
4B data via the TxD0~3 inputs of the MII. These inputs are sampled by the device on the
rising edge of Tx-clk and passed to the 4B/5B encoder to generate the 5B code-group used
by 100Base-TX.
Idle code-groups: In order to establish and maintain the clock synchronization, the device
needs to keep transmitting signals to the medium. The device generates idle code-groups
for transmission when there is no data sent by the MAC.
Start-of-stream delimiter-SSD (/J/K/): In a transmission stream, the first 16 nibbles are SFD
(1 byte) and MAC preamble (7 byte). In order to let partner delineate the boundary of a data
transmission sequence and to authenticate carrier events, the device replaces the first 2
nibbles of the MAC preamble with /J/K/ code-groups.
End-of-stream delimiter-ESD (/T/R/): In order to indicate the termination of the normal data
transmissions, the device inserts 2 nibbles of /T/R/ code-group after the last nibble of FCS.
Scrambling: all the encoded data (including the idle, SSD, and ESD code-groups) is passed
to the data scrambler to reduce the EMI and spread the power spectrum using a 10-bit
scrambler seed loaded at the beginning.
Parallel-to-serial data conversion, NRZ to NRZI, NRZI to MLT3: after being scrambled, the
transmission data with 5B type at 25 MHz is converted to serial bit stream at 125 MHz by the
parallel-to-serial function. After being serialized, the transmission serial bit stream is further
converted from NRZ to NRZI format. This NRZI conversion function can be bypassed if bit 7
of the RN13 register is cleared as 0. After being NRZI converted, the NRZI bit stream is
passed through the MLT3 encoder to generate the TP-PMD specified MLT3 code. The MLT3
code lowers the frequency and reduces the energy of the transmission signal in the UTP
cable and also allows the system to meet the FCC specification for EMI.
Doc ID 17049 Rev 1
ST802RT1A, ST802RT1B