Advanced Configuration and Power Interface Specification

ACPI Software Programming Model
Field
Byte
Length
Byte
Offset
Description
EC_CONTROL 12 36 Contains the processor relative address, represented in Generic
Address Structure format, of the Embedded Controller Command/
Status register.
Note: Only System I/O space and System Memory space are
valid for values for Address_Space_ID.
EC_DATA 12 48 Contains the processor-relative address, represented in Generic
Address Structure format, of the Embedded Controller Data
register.
Note: Only System I/O space and System Memory space are
valid for values for Address_Space_ID.
UID 4 60 Unique ID–Same as the value returned by the _UID under the
device in the namespace that represents this embedded
controller.
GPE_BIT 1 64 The bit assignment of the SCI interrupt within the GPEx_STS
register of a GPE block described in the FADT that the embedded
controller triggers.
EC_ID Variable 65 ASCII, null terminated, string that contains a fully qualified
reference to the namespace object that is this embedded
controller device (for example, “\\_SB.PCI0.ISA.EC”). Quotes are
omitted in the data field.
ACPI OSPM implementations supporting Embedded Controller devices must also support the
ECDT. ACPI 1.0 OSPM implementation will not recognize or make use of the ECDT. The
following example code shows how to detect whether the Embedded Controller operation regions
are available in a manner that is backward compatible with prior versions of ACPI/OSPM.
Version 6.0 157