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Programmer’s Reference Manual 113
Intel® High Definition Audio BIOS Considerations
A codec verb is a 32-bit DWord command sent to a codec by software that contains the following
information:
• Codec address and Node ID of the target node in the codec
• Command to be performed by the target node
• Data payload (if any)
Below is the format of a Verb dword.
There are two ways for software to send verbs to and receive response data from codecs over the
Intel® HD Audio codec link: Using CORB/RIRB (Command Output Ring Buffer / Response Input
Ring Buffer), or using Immediate Command/Immediate Response register pair. See the Intel® HD
Audio Specification for details of register description and programming interface.
4.1.2.2 Codec Verb Table
For each codec present on the Intel® HD Audio codec link, a corresponding pre-defined “Codec
Verb Table” must be available to BIOS. The Codec Verb Tables are based on codec specific
information (coded datasheet) and platform design specific information (schematics) and are built
by BIOS writers and platform designers. The table contains a list of 32-bit “Verb”s (command and
data payload) to be sent to the corresponding codec over the Intel® HD Audio codec link.
Figure 4-2. Intel
®
High Definition Audio Codec Node Structure and Addressing
NID= 3
Strt= 9
Root Node NID=0 Strt=3
NID = 4
Strt = 12
Azalia Codec
NID = 5
Strt = 68
NID=12
NID=10
NID=11 NID=68
NID=13
NID=9
NID=69
NID=70
Root Node
Function Group Nodes
(e.g., Audio, Modem)
Widget Nodes
(e.g., Pin, DAC)