ADLINK Technology cPCI-3920 Series, User Manual

Page: 40 / 106

30 Functional Description
A reset will be generated by the following conditions:
X
+5 V supply falls below 4.1 V (typ.)
X
+3.3 V supply falls below 2.93 V (typ.)
X
Pushbutton ´RESET" pressed (only on 8HP)
X
Watchdog overflow
X
CompactPCI backplane PRST# input (CompactPCI con-
nector J2, pin C17)
SMBus Devices
The cPCI-3920 provides a System Management Bus (SMBus)
for access to several system monitoring and configuration
functions. The SMBus consists of a two-wire I2C bus interface.
The following table describes the function and address of every
onboard SMBus device.
Table 3-2: SMBus Devices and Addresses
Thermal Management/ System Monitoring
The IICH can be used to monitor several critical hardware param-
eters of the system, including power supply voltages, fan speeds
and temperatures, all of which are very important for the proper
operation and stability of a high-end computer system. The IICH
provides an LPC bus interface.
The vo12 V, +5 V, +3.3 V, +2.5 V, and Vcore are super-
vised. One fan tachometer output can be measured using the
IICH’s FAN1 input. One pulse width modulation (PWM1) output
can be used for FAN speed control.
The temperature sensors on the IICH monitor the CPU tempera-
ture and the ambient temperature around the IICH to ensure that
the system is operating at a safe temperature level. If the CPU
Device SMBUS Address
Clock Buffer DCh
Clock Generator D2h
SPD A0h
EEPROM (Board VPD) AEh