HP Compaq dc7800 Series Technical Reference Manual page 54

System Support
■
Chassis and board ID
■
Hood (cover) sensor and lock detect
■
Media card reader detect
■
S4 state indicator
■
USB port over-current detect
■
Flash security override
■
Serial port detect
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REQn#/GNTn# sigal control
■
Password enable
■
Boot block enable
I/O Controller Functions
In addition to the serial and parallel port functions, the SCH5327 I/O controller provides the
following specialized functions through GPIO ports:
■
Power/Hard drive LED control for indicating system events (refer to Table 4-8)
■
Hood lock/unlock controls the lock bar mechanism
■
Thermal shutdown control turns off the CPU when temperature reaches certain level
■
Processor present/speed detection detects if the processor has been removed. The occurrence
of this event will, during the next boot sequence, initiate the speed selection routine for the
processor.
■
Legacy/ACPI power button mode control uses the pulse signal from the system's power
button and produces the PS On signal according to the mode (legacy or ACPI) selected.
Refer to chapter 7 for more information regarding power management.
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