Sun Microsystems Netra T4 AC100 Service And System Reference Manual page 175

Motherboard
SEEPROM
BBC
AT24C64
0
I2C
DIMM0 DIMM1
Ctl
SEEPROM SEEPROM
#0
AT24C64 AT24C64
1
2
3
4
I2C
SEEPROM
Ctl
AT24C64
#1
Temperature
Sensor
Max1617
Master/Slave
5
87LPC762
FIGURE 10-12
In addition, located on the motherboard is a soldered I2C SEEPROM containing the
FRU ID structure.
POST and OBP also access the SEEPROMs in each of the DIMMs, which indicate
their density and type. This data can be used to configure the active memory
controller. The Ethernet address and host ID can be transferred to another system (in
case of motherboard failure) by using the system configuration card and reader to
overwrite the EEPROM contents with the original motherboard's identification
parameters.
The I2C bus is also used to monitor CPU die temperatures through sensors in each
CPU chip and on the processor board. The I2C bus monitors the fan speed, using
LM80s on the PDB, and power supply status.
DIMM2 DIMM3
SEEPROM SEEPROM
AT24C64 AT24C64
Spare
Spare
Spare
CPU0
SEEPROM
AT24C64
Temperature
Max1617
I2C Bus
DIMM4 DIMM5
SEEPROM SEEPROM
AT24C64 AT24C64
CPU1
Sensor
Chapter 10 Functional Description
DIMM6 DIMM7
SEEPROM SEEPROM
AT24C64 AT24C64
LOMlite
10-21