Pre-Production
WM8850
DAC2 and DAC3 are a high performance stereo DACs that supports all common sample rates from
8kHz to 192kHz and data widths of 16, 20, 24 and 32-bit (Float-32).
The sample rate and word length of the data played back by the DAC2 or DAC3 nodes is set using
the Stream Format Verb. Table 24 below shows the required settings for Base, Mult and Div as part
of the Stream Format Verb to obtain the required sample rate.
SAMPLE RATE
8kHz
BASE
0h
MULT
0h
DIV
5h
3h
2h
1h
1h
2h
0h
0h
0h
0h
0h
0h
11.025kHz
16kHz
1h
0h
0h
0h
22.05kHz
24kHz
1h
0h
0h
0h
32kHz
0h
1h
44.1kHz
48kHz
1h
0h
0h
0h
88.2kHz
96kHz
1h
1h
0h
1h
176.4kHz
192kHz
1h
3h
0h
3h
Table 24 DAC2 and DAC3 Supported Sample Rate Settings
Note: Other settings of Base, Mult and Div are reserved and should not be set.
DAC2 and DAC3 provide digital gain, allowing the signal level to be adjusted between 0dB and
−63.5dB in 0.5dB steps. Gain can be applied to left and right channels independently if required.
Additionally, a digital softmute function is available – again this can be applied to separate channels
as required. The gain of each DAC is controlled using the Amplifier Gain/Mute Verb in the required
node.
Under default conditions, the DAC2 and DAC3 nodes will process data received from the HDA
interface. It is also possible to select S/PDIF Rx as the data source, using the vendor-specific Internal
Path Verb.
Note that, when the S/PDIF Rx node is selected as the input to any of DAC1, DAC2 or DAC3, the
Internal Path Verbs in all the other DAC nodes are updated to use the S/PDIF Rx node also. It is not
possible to route the HDA Link to any DAC at the same time as routing the S/PDIF Rx node to
another DAC.
When the S/PDIF Rx node is selected as the input to the DAC nodes, the Stream Format Verb for
each DAC node becomes read-only and is set according to the settings in the S/PDIF Rx node.
SET VERB
BIT
BITFIELD
NAME
DEFAULT
DESCRIPTION
773h
7:0
Path Sel
00h
Selects source of DAC2 or DAC3 node:
00h = DAC takes data from HDA Link
05h = DAC takes data from S/PDIF Rx
All other values of Path Sel are reserved.
Note: When using the Internal Path Verb to use S/PDIF Rx as the data source of DAC2 or DAC3 it is
recommended that the S/PDIF Rx node (NID=05h) is enabled after setting Path Sel=05h. Failure to
do so may result in a one sample delay between left and right channels.
PP, April 2011, Rev 3.2
55
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
