w83877atd Winbond Electronics Corp America, w83877atd Datasheet - Page 154

• Manufacturer Part Number: w83877atd
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

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.
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.
Global STBY
Device Trap
Device Idle
PM Timer
Timers
Timer
IRQs
SMI events
SCI events
SCI_EN
1
0
SMI Logic
IRQs
SCI Logic
- 150 -
IRQs
SMI_EN
State machine
Sleep/Wake
Publication Release Date: April 1998
SMI output
SCI output
Logic
Logic
W83877ATF
SMI
SCI
Clock
Control
WAK_STS
Version 0.51