Compaq Deskpro EP 6233 - 82371 South Bridge Gpio Configuration

Technical Reference Guide
Compaq Deskpro EP Series of Personal Computers
First Edition–- April 1998
4-47
4.7.2 82371 SOUTH BRIDGE GPIO CONFIGURATION
The 82371 South Bridge component includes a number of single and dual purpose pins available
as general purpose input/output (GPIO) ports. The GPIO ports are configured during POST by
BIOS through the PCI configuration registers B0-B3h (82371, function 0). Tables 4-20 and 4-21
list the utilization of the GPIO ports in this system.
Table 4–20.
82371 South Bridge General Purpose Input Port Utilization
Table 4-20.
82371 South Bridge General Purpose Input Port Utilization
GP Input Port Function
GPI #0 IOCHK- function for ISA bus.
GPI #1 Wake up event. If ACPI events are enabled high-to-low transition of this input will wake up
system. WU EVENT- is caused by ring or magic packet event.
GPI #2 Magic packet. Will be high if magic packet event occurred from optional NIC through wake-
on-LAN (WOL) header P9. Cleared by GPO #9.
GPI #3 Ring status. Will be high if ring event occurred from COM1 serial port. Cleared by GPO #10.
GPI #4 Not used.
GPI #5 VBAT OK. Will be high if CMOS is valid and low battery condition has not occurred. Cleared
if low battery condition occurs.
GPI #6 AC On (SW1-1) Status: 0 = SW1-1 is On, 1 = SW1-1 is Off.
GPI #7 Not used.
GPI #8 Therm/MPKt. Controlled by BIOS as follows: Set for THERM unless system was resumed
from Soft Off by WOL (MPKT) event, in which BIOS will disable SMIs from MPKT and
resume events. BIOS will set THERM, disable THERM_EN, and change GPI8 to THERM.
THERM status will be cleared and THERM_EN will be enabled to produce SMIs. Once
MPKT is deasserted BIOS will get an SMI from THERM when the NIC driver loads. BIOS
will change THERM back to GPI8 and enable MPKT to resume the system in the SMI
handler.
GPI #9 Not used.
GPI #10 WU IRQ1. Will, in S1 state, be high if an IRQ1 (keyboard interrupt) occurred.
GPI #11 VSBLANK. If high results in an SMI- being generated.
GPI #12 WU IRQ12. Will, in S1 state, be high if an IRQ12 (mouse interrupt) occurred.
GPI #13-15 Not used.
GPI #16 Password disable status: 0 = disabled, 1 = enabled.
GPI #17 Primary IDE cable type: 0 = 80-pin cable attached, 1 = 40-pin cable attached.
GPI #18 Secondary IDE cable type: 0 = 80-pin cable attached, 1 = 40-pin cable attached.
GPI #19 Chassis fan status (valid if GPO #30 = 1): 0 = fan not connected, 1 = fan connected.
GPI #20, 21 Not used.