Specifications

AMD Geode™ GeodeROM Functional Specification 231
System Management Mode Software
32087C
15.12.14 EVENT_TIMER
A VSM may request to be notified every n milliseconds. This event is generated when the requested time interval has
expired. The timer request remains active until the VSM cancels the request via SYS_UNREGISTER_EVENT. Since a
VSM can request more than one timer to run concurrently, a handle may be specified when each timer is registered. When
a timer elapses, the corresponding handle is passed as a parameter to distinguish among multiple timers.
• Parameter1
— Bit 31 = Reserved
— Bits [30:0] = Interval bits
• Parameter2
— Handle
15.12.15 EVENT_VIRTUAL_REGISTER
Access to a virtual register has occurred. A VSM is only sent this message for virtual register accesses for class(es) for
which it registered.
• Parameter1
— Virtual register
– Bits [15:8] = VR class
– Bits [7:0] = Class index
• Parameter2
— 00h = WORD read
— 01h = WORD write
• Parameter3
— Data (valid only if access is a write)
15.12.16 EVENT_A20
A change in the A20 mask has occurred. This may be either by bit 1 of I/O Port 92h or by issuing a keyboard controller com-
mand.
• No Parameters
15.12.17 EVENT_NMI
An NMI has occurred.
• No Parameters
15.12.18 EVENT_GT1
The General Purpose Timer 1 has expired.
• Parameter1
— Timeout in seconds
• Parameter2
— Mask of devices that can reset GT1
– Bits [7:5] = Reserved
– Bit 4 = Secondary hard disk
– Bit 3 = Keyboard/Mouse
– Bit 2 = Parallel/Serial
– Bit 1 = Floppy disk
– Bit 0 = Primary hard disk