Compaq Deskpro EP 6233 - Page 98

Chapter 4 System Support
Compaq Deskpro EP Series of Personal Computers
First Edition - April 1998
4-48
Table 4–21. 82371 South Bridge General Purpose Output Port Utilization
Table 4-21.
82371 South Bridge General Purpose Output Port Utilization
GP Output Port Function
GPO #0 PCI reset. When low will generate a PCI RST- to PCI slots.
GPO #1-7 ISA bus address signals LA17-23.
GPO #8 Power button mode: When cleared puts button in ACPI mode. When set puts button in
legacy mode.
GPO #9 Clear magic packet status: When cleared (0) clears GPI #2.
GPO #10 Clear ring status: When cleared (0), clears GPI #3
GPO #11 CMOS battery set: When set and then cleared (1,0) sets GPI #5 after CMOS initialization
after low battery condition.
GPO #12 Diskette drive write protect: When cleared, prevents all writes to diskette, is set (1) for
normal (diskette determines) protection.
GPO #13 BIOS ROM write-protect: When cleared disables write protection (allow ROM flashing),
write 1 to write-protect ROM.
GPO #14 Wake up function clock. Write 0, 1, then 0 successively to load the values of power
management event (GPO #26), ring (GPO #27), and magic packet (GPO #28) into a control
latch.
GPO #15 Not used.
GPO #16 Power management suspend control signal.
GPO #17 CPU clock stop. When cleared inhibits the clock generator from producing CPU clock.
GPO #18 PCI clock stop. When cleared inhibits the clock generator from producing PCI clock.
GPO #19 Sleep LED control. When set results in power LED to blink at 1 Hz. When cleared, power
LED is continuously on.
GPO #20 Power management suspension control signal.
GPO #21 Not used.
GPO #22, 23 X-bus control signals.
GPO #24 Not used.
GPO #25 SMI generation control signal.
GPO #26 Power management event control: When set (1), inhibits PME- generation. When cleared
(0) enables PME- generation.
GPO #27 Ring event enable/disable: When cleared, inhibits RING- generation. When set enables
RING- generation.
GPO #28 Magic packet enable/disable: When set, inhibits MPKT- generation. When cleared, enables
MPKT- generation.
GPO #29 Power state restore after power outage: When cleared, will cause system to power up “off”
following power restoration (unless AC-On DIP switch is set to “On”). When set, system
will revert to power state prior to outage. Diagnostic and ROMPAQ software clears this bit.
GPO #30 Fan control. When cleared, chassis and power supply fans are disabled. When set, chassis
and power supply fans are enabled. On-board circuitry does
not
override this function.