LU82551QM Intel, LU82551QM Datasheet - Page 53

• 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

8.4
8.5
8.6
8.7
8.8
Datasheet
Watchdog
A watchdog packet is sent when the watchdog timer expires. Software can use these registers to
indicate the state of the system. For example, the watchdog timer can be set and enabled upon
initial power up. If the system hangs before reaching this point, the watchdog timer expires and the
82551QM notifies the management console. When the watchdog timer expires, 82551QM enters
Force TCO mode, enables reception of management packets, and sends a watchdog SOS packet if
LINK is valid. Because a hard power loss can happen without software knowledge, it is important
to disable watchdog events during low power modes. If a hard power loss occurs, an EEPROM
load will reload the watchdog timer and possibly set it to be enabled. At the point that
PWR_GOOD transitions high, the watchdog timer will become enabled (if configured enabled)
and start counting from its initial loaded value, essentially restarting the boot-up time-out timer.
Advanced Power Management Modes
Upon receiving certain packets, 82551QM can perform Advanced Power Management (APM)
transitions such as reset, power-up, and power-down.
Polling
82551QM acts as a master on the SMB to poll slaves for status, or set APM bits remotely. Target
addresses to be polled are stored in the 82551QM’s configuration EEPROM.
Link Loss
If 82551QM detects a link loss for more than 5 seconds, it transmits an alert packet when the link is
recovered.
Acknowledge
Management packets transmitted by 82551QM can be classified in three categories: SOS packets
(event notifications), one-shot packets (receive acknowledgments, heartbeats and pongs), and ARP
replies. 82551QM can be configured to retransmit each SOS packet a pre-defined number of times
at a predefined interval until the SOS packet has been acknowledged. This capability adds
reliability to ASF data transfer.
Networking Silicon — 82551QM
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