82371AB Datasheet, PDF (213/284 Pages) Intel Corporation – PCI-TO-ISA / IDE XCELERATOR PIIX4

E
82371AB (PIIX4)
1. If there is a need to monitor accesses to the IDE controller to keep the global standby timer from expiring,
then the IRQs should be enabled (GRLD_EN_IRQ) as a reload event for the global standby timer.
2. If there is a need to monitor an external IDE controller for idleness, use the following algorithm
a. Disable the external IDE controller. Set the PIIX4 to trap on the IDE access and enable the internal IDE
controller.
b. When the SMI is generated, the idle timer can be started, the internal IDE controller disabled, and the
instruction redone to the external IDE controller. The IDE device is then assumed to be active during idle
timer count down.
c. When the idle timer times out, an SMI is generated and the PIIX4 should again be set to trap, the
external IDE device disabled, and the idle timer started.
d. If the idle timer times out before the trap occurs, then the external IDE controller is idle and can be put
into a lower power mode. The PIIX4 is then set up to trap as in number 3, below.
e. If the trap occurs first, the IDE device is not idle. The BIOS then returns to step b, above.
3. If there is a need to perform I/O trapping on an external IDE controller, set the PIIX4 to trap on the IDE
access and enable the PIIX4 internal IDE controller. When the SMI is generated, the internal IDE controller
can be disabled, the external controller enabled, and the I/O cycle restarted.
Table 33. Peripheral Device Overview
Device Access
Reload
Peripheral Device
Access Address
DACK#
GPI Idle Timer Global Fast Slow
Count Standby Burst Burst
0. Primary IDE
Drive 0
1F0h–1F7h
3F6h
IDE
PDDACK#
CNT-A
x
x
1. Primary IDE
Drive 1
1F0h–1F7h
3F6h
IDE
PDDACK#
GPI5 CNT-A
x
x
x
2. Secondary IDE 170h–177h
Drive 0
376h
IDE
SDDACK#
GPI6 CNT-A
x
x
x
3. Secondary IDE 170h–177h
Drive 1
376h
(Software SMI
Timer)
IDE
SDDACK#
GPI0 SWCNT
x
x
x
4. Audio
300h–303h MIDI
310h–313h MIDI
320h–323h MIDI
330h–333h MIDI
200h–207h GAME
388h–38Bh ADLIB
220h–233h SB-8/16
240h–253h SB-8/16
260h–273h SB-8/16
280h–293h SB-8/16
530h–537h MSS
604h–60Bh MSS
E80h–E87h MSS
F40h–F47h MSS
any/all:
DACK[x]#
0,1,3,5,6,7
GPI13 CNT-B
x
x
5. FDD
3F0h–3F5h, 3F7h
370h–375h, 3F7h
DACK2#
GPI14 CNT-B
x
x
x
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