WM8850 datasheet(33/223 Pages) WOLFSON

33 / 223 page

Pre-Production

WM8850

PP, April 2011, Rev 3.2

Mono Streams

All converters are stereo. Where an input converter (ADC, S/PDIF Rx) is associated with a mono

stream, only the left channel (channel 0) will be sent on the HDA Link.

In mono mode, right channel modules in the ADC will be disabled to save power.

Where an output converter (DAC, S/PDIF Tx) is associated with a mono stream, both left and right

channels render the same samples. If both left and right DAC outputs are not desired, the unwanted

channel can be muted.

A stream is assumed to be mono when its Chan control in the Stream Format Verb is set to 0. The

Channel control in the Converter Stream, Channel Verb should be set to 0, although any setting of

this register gives the same behaviour in mono mode.

ILLEGAL REGISTER VALUES

Should the user set verb registers to illegal, unsupported or reserved values, WM8850 behaviour is

undefined.

Writing to Reserved registers has no effect.

RESPONSE FIELD

Valid Bit

Bit [35] of the Response Field is defined as the Valid Bit. Section 7.3.1 of the HDA specification

states: “A 1 in the Valid bit position indicates the Response Filed contains a valid response, which the

controller will place in the RIRB; a 0 indicates there is no response.”

The WM8850 will set the Valid Bit for all responses, except null responses.

We define a null response as a response to a command that contains an invalid verb (a command

where NID=0h, and Verb=0h), or a response to a command with a CODEC address (CAd) that does

not match the WM8850 CAd. Either of these commands can be considered as a null command.

We define a non-defined command as a command that has no meaning (i.e. a NID that is not within

the WM8850, or a Verb ID that is not supported for the given node). The WM8850 will set the Valid

Bit for non-defined commands.

WM8850 Datasheet(PDF) 33 Page - Wolfson Microelectronics plc