GE CM6, Hardware Reference Manual

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• MV88E1118 Giga Phy B
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Temperature
One National Semiconductor LM86 temperature sensor is implemented on the
CM6 board. The sensor is located close to the CPU and shows the die-
temperature of the CPU and the local onboard temperature. The sensor has two
programmable over-temperature outputs integrated, which is used to protect the
CPU for overheating.
The first stage is not used in the current CM6 implementation, the second stage
is programmed to 110°C die temperature or 95°C board temperature if this
temperature is reached the core voltage is switched off. The limit may be
reprogrammed to user defined values.
If the CPU core power is switched-off by the temperature limit the board can
only be re-powered with a reset switch actuation or a power-off/on cycle.
SMBus devices
The CM6 uses the two serial two-wire I
2
C busses controlled by MPC8641 to
communicate with several onboard devices:
I2C Bus #1
Device Designator SMBus address
Non-volatile digital switch U1106 1010 111Xb
I2C Bus #2:
Table 21: SMBus devices
Device Designator SMBus address
Clock synthesizer * U1000 1101 001Xb
SPD EEprom * U1981 1010 000Xb
Factory EEprom * U1981 1010 001Xb
User EEprom U1983 1010 01nXb
Temperature sensor LM86 U1982 1001 100Xb
Devices marked by * are handled by the boot loader. It is strongly
recommended not to access these devices under user software.
An 'X' at bit 0 represents the R/#W bit and 'n' a random address bit.
Serial EEPROMs
For storage of SPD and factory user data a serial EEPROM is implemented on
the CM6 board. It is a standard 24C04 type EEPROM with 512 bytes. The user
EEPROM is a 24C1024 type with 128 kByte.
GE Intelligent Platforms – CM6 Hardware Reference Manual, Fourth Edition Page 61