W83877ATF Datasheet, PDF (154/191 Pages) Winbond – enhanced version from Winbonds most popular I/O chip W83877F

W83877ATF
8.3 ACPI Registers Features
W83877ATF supports both the ACPI and legacy power managements. The switch logic of the power
managment block generates an SMI interrupt in the legacy mode and an SCI interrupt in the ACPI
mode. For the legacy mode, the SMI_EN bit is used. If it is set, it routes the power management
events from the SMI interrupt logic to the SMI output pin. For the ACPI mode, the SCI_EN bit is used.
If it is set, it routes the power management events to the SCI interrupt logic. The SMI_EN bit is
located in the CR3A register and the SCI_EN bit is located in the PM1 register block. See the
following figure for an illustration.
SMI events
IRQs
PM Timer
IRQs
SMI Logic
0
1
SCI events
SCI_EN
SCI Logic
Device Idle
Timers
Device Trap
Global STBY
Timer
SMI_EN
SMI output
Logic
SCI output
Logic
IRQs
Sleep/Wake
State machine
SMI
SCI
WAK_STS
Clock
Control
The SMI interrupt is routed to pin SMI , which is dedicated for the SMI interrupt output. Another way
to output the SMI interrupt is to route to pin IRQSER, which is the signal pin in the Serial IRQ mode.
The SCI interrupt is routed to pin SCI , which is dedicated for the SCI function. The other way to
output the SCI interrupt is to route to one interrupt request signal pin IRQA~H, which is selected
through CR31 bit[7:4]. Another way is output the SCI interrupt is to route to pin IRQSER.
- 150 -
Publication Release Date: April 1998
Version 0.51