Gpio Functions - HP Compaq dc7900 USDT Technical Reference Manual

System Support

4.6.2 GPIO Functions

ICH10 Functions
The ICH10 provides various functions through the use of programmable general purpose
input/output (GPIO) ports. These systems use GPIO ports and associate registers of the ICH10
for the following functions:
■
PCI interupt request control
■
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
■
REQn#/GNTn# sigal control
■
Password enable
■
Boot block enable
SIO Controller Functions
In addition to the serial and parallel port functions, the SIO 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.
4-16 www.hp.com Technical Reference Guide