Advanced Configuration and Power Interface Specification

Power Source and Power Meter Devices
slave address 1 (0x09) is placed in the embedded controller’s Alarm Address Register and the EC’s
Status Register’s Alarm bit is set. The embedded controller then asserts an SCI.
10.1.1.2 Smart Battery Charger with optional System Manager or Selector
A Smart Battery Charger that contains the optional System Manager or Selector function (as
indicated by the ChargerSpecInfo() command register, 0x11, bit 4) is required to generate an SMBus
Alarm Notify on a battery or AC status change. The content of the Smart Battery Charger with an
optional System Manager, the BatterySystemState() command register (0x21) (or in the case of an
optional Selector, the SelectorState() (0x01) ), is placed in the EC’s Alarm Data Registers, the Smart
Battery Charger’s slave address (0x09) is placed in the embedded controller’s Alarm Address
Register, and the embedded controller’s Status Register’s Alarm bit is set. The embedded controller
then asserts an SCI.
10.1.1.3 Smart Battery System Manager
The Smart Battery System Manager is required to generate an SMBus Alarm Notify on a battery or
AC status change. The content of the Smart Battery System Manager’s BatterySystemState()
command register (0x01) is placed in the EC’s Alarm Data Registers, the Smart Battery System
Manager’s slave address (0x0A) is placed in the EC’s Alarm Address Register, and the embedded
controller’s Status Register’s Alarm bit is set. The embedded controller then asserts an SCI.
10.1.1.4 Smart Battery Selector
The requirements for the Smart Battery Selector are the same as the requirements for the Smart
Battery System Manager, with the exception that the contents of the SelectorState() command
register (0x01) are used instead of BatterySystemState(). The Smart Battery Selector is a subset of
the Smart Battery System Manager and does not have the added support for simultaneous charge/
discharge of multiple batteries. The System Manager is the preferred implementation.
10.1.2 Smart Battery Objects
The Smart Battery subsystem requires a number of objects to define its interface. These are
summarized below:
Table 10-271 Smart Battery Objects
Object
_HID
_SBS
Description
This is the hardware ID named object that contains a string. For Smart Battery subsystems, this
object returns the value of “ACPI0002.” This identifies the Smart Battery subsystem to the Smart
Battery driver.
This is the Smart Battery named object that contains a DWORD. This named object returns the
configuration of the Smart Battery.
1. Notice that the 1.0 SMBus protocol specification is ambiguous about the definition of the “slave address”
written into the command field of the host controller. In this case, the slave address is actually the combination of the
7-bit slave address and the Write protocol bit. Therefore, bit 0 of the initiating device’s slave address is aligned to bit
1 of the host controller’s slave command register, bit 1 of the slave address is aligned to bit 2 of the controller’s slave
command register, and so on.
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