Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
The following ASL code illustrates how a device supporting the Read/Write Quick protocol should
be accessed:
OperationRegion(TOP1, GenericSerialBus, 0x00, 0x100) // GenericSerialBus device at command value
offset 0
Field(TOP1, BufferAcc, NoLock, Preserve)
{
Connection(I2CSerialBus(0x5a,,100000,,"\_SB.I2C",,,,RawDataBuffer(){1,6}))
AccessAs(BufferAcc, AttribQuick) // Use the GenericSerialBus Read/Write Quick protocol
FLD0, 8 // Virtual register at command value 0.
}
/* Create the GenericSerialBus data buffer */
Name(BUFF, Buffer(2){})
CreateByteField(BUFF, 0x00, STAT)
/* Signal device (e.g. OFF) */
Store(FLD0, BUFF)
If(LEqual(STAT, 0x00)) {…}
// Create GenericSerialBus data buffer as BUFF
// STAT = Status (Byte)
// Invoke Read Quick transaction
// Successful?
/* Signal device (e.g. ON) */
Store(BUFF, FLD0)
// Invoke Write Quick transaction
In this example, a single field element (FLD0) at offset 0 is defined to represent the protocol’s read/
write bit. Access to FLD0 will cause a GenericSerialBus transaction to occur to the device. Reading
the field results in a Read Quick, and writing to the field results in a Write Quick. In either case data
is not transferred—access to the register is simply used as a mechanism to invoke the transaction.
5.5.2.4.5.3.2 Send/Receive Byte (AttribSendReceive)
The GenericSerialBus Send/Receive Byte protocol (AttribSendReceive) transfers a single byte of
data. Like Read/Write Quick, command values are not used by this protocol and thus only a single
element (at offset 0) can be specified in the field definition.
The following ASL code illustrates how a device supporting the Send/Receive Byte protocol should
be accessed:
OperationRegion(TOP1, GenericSerialBus, 0x00, 0x100) // GenericSerialBus device at command value
offset 0
Field(TOP1, BufferAcc, NoLock, Preserve)
{
Connection(I2CSerialBus(0x5a,,100000,,"\_SB.I2C",,,,RawDataBuffer(){1,6}))
AccessAs(BufferAcc, AttribSendReceive) // Use the GenericSerialBus Send/Receive Byte protocol
FLD0, 8 // Virtual register at command value 0.
}
// Create the GenericSerialBus data buffer
Name(BUFF, Buffer(3){})
// Create GenericSerialBus data buffer as BUFF
CreateByteField(BUFF, 0x00, STAT) // STAT = Status (Byte)
CreateByteField(BUFF, 0x02, DATA) // DATA = Data (Byte)
// Receive a byte of data from the device
Store(FLD0, BUFF)
// Invoke a Receive Byte transaction
If(LEqual(STAT, 0x00))
// Successful?
{
// DATA = Received byte…
}
234 April, 2015 Version 6.0