Functional Description
CP605
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© 2004 Kontron Modular Computers GmbH
ID 25095, Rev. 07
2509
5.07.UG.VC.041005/14151
8
2.4.2
Watchdog Timer
The CP605 employs a watchdog timer, which forces either an IRQ5, NMI, or Reset condition
(configurable in the watchdog register). The watchdog time can be programmed in 12 steps
ranging from 125 msec up to 256 seconds. If the watchdog timer is enabled, it cannot be
stopped.
2.4.3
Battery
The CP605 utilizes a 3.0V “coin cell” lithium battery for the RTC.
2.4.4
Reset
The CP605 is automatically cold reset by a precision voltage monitoring circuit that detects a
drop in voltage below the acceptable operating limit of 4.725 V for the 5 V line and below 3.0 V
for the 3.3 V line, or in the event of a power failure of the DC/DC converter. Other reset sources
include the watchdog timer and the local push-button switch. The CP605 responds to any of
these sources by initializing local peripherals.
A reset will be generated by the following conditions:
• +5 V supply falls below +4.75 V
• +3.3 V supply falls below +3.0 V
• Power failure of the DC/DC converter for the processor
• Push button "RESET" pressed
• Watchdog timeout
• CompactPCI backplane PRST input
2.4.5
Local SMBus Devices
The CP605 provides a System Management Bus (SMBus) for access to several system
monitoring and configuration functions. The SMBus consists of a two-wire I
²
C-bus interface and
several serial devices. The following table describes the function and address of every onboard
SMBus device.
2.4.6
Thermal Management / System Monitoring
The LM81 can be used to monitor several critical hardware parameters 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 LM81 provides an I
²
C serial
bus interface.
The voltages of the onboard power supply, which are: +12 V, -12 V, +5 V, +3.3 V, VCore, and
the battery voltage are supervised. Two fan tachometer outputs can be measured using the
LM81’s FAN1 and FAN2 inputs.
Table 2-3: SMBus Device Addresses
DEVICE
SMBUS ADDRESS
Temperature Sensor MAX1617
0011000Xb
Hardware Monitor LM81
0101100Xb
EEPROM
1010XXXXb
