LU82551QM Intel, LU82551QM Datasheet - Page 41

• Manufacturer Part Number: LU82551QM
• Manufacturer: Intel

Specifications of LU82551QM

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 196
• Lead Free Status / RoHS Status: Compliant

5.8
5.8.1
Datasheet
Table 14. EEPROM Address Map (Continued)
Note: Refer to the 82551QM/ER/IT EEPROM Map and Programming Information for more details.
10/100 Mbps CSMA/CD Unit
The 82551QM CSMA/CD unit implements both the IEEE 802.3 Ethernet 10 Mbps and IEEE
802.3u Fast Ethernet 100 Mbps standards. It performs all the CSMA/CD protocol functions such as
transmission, reception, collision handling, etc. The 82551QM CSMA/CD unit communicates with
the internal PHY unit through a standard Media Independent Interface (MII), as specified by IEEE
802.3, Chapter 22. This is a 10/100 Mbps mode in which the data stream is nibble-wide and the
serial clocks run at either 25 or 2.5 MHz.
Full Duplex
When operating in full duplex mode the 82551QM can transmit and receive frames simultaneously.
Transmission starts regardless of the state of the internal receive path. Reception starts when the
internal PHY detects a valid frame on the receive differential pair of the PHY.
The 82551QM operates in either half duplex mode or full duplex mode. For proper operation, both
the 82551QM CSMA/CD module and the PHY unit must be set to the same duplex mode. The
CSMA duplex mode is set by the 82551QM Configure command or forced by the settings in the
PHY unit’s registers.
The PHY duplex mode is set either by Auto-Negotiation or, if Auto-Negotiation is disabled, by
setting the full duplex bit in the Management Data Interface (MDI) Register 0, bit 8. By default, the
internal PHY unit advertises full duplex ability in the Auto-Negotiation process regardless of the
duplex setting of the CSMA unit. The CSMA configuration should match the result of the Auto-
Negotiation.
The selection of duplex operation (full or half) and flow control is done in two levels: MAC and
PHY. The MAC duplex selection is done only through the CSMA configuration mechanism (in
other words, the Configure command in software).
32h – 3Eh
F8h:FEh
40h:F7h
Word
3Fh
FFh
256-word EEPROM Checksum, high byte
64-word EEPROM Checksum (high byte)
High Byte (Bits 15 – 8)
Controlled by the ASF Agent
Reserved for Software
Reserved
256-word EEPROM Checksum, low byte
64-word EEPROM Checksum (low byte)
Networking Silicon — 82551QM
Low Byte (Bits 7 – 0)
35