W83877ATG Nuvoton Technology Corporation of America, W83877ATG Datasheet - Page 157

• Manufacturer Part Number: W83877ATG
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83877ATG

• Lead Free Status / RoHS Status: Supplier Unconfirmed

11.3 ACPI Registers Features
W83877ATF/ATG 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
0
1
SMI Logic
IRQs
SCI Logic
- 150 -
IRQs
W83877ATF/W83877ATG
SMI_EN
State machine
Sleep/Wake
SMI output
SCI output
Logic
Logic
SMI
SCI
Clock
Control
WAK_STS