WM8850
Pre-Production
Figure 6 Single Ended (Left) and Differential (Right) External Connections
Port-E supports presence detect. This can be read directly from the Pin Sense Verb.
If nothing is plugged into Port-E it is possible to use an automute function which will automatically
replace the samples in the stream with zeros, thus avoiding any noise being transmitted when there is
no input. This function can be enabled using the vendor-specific Auto-Mute Control Verb.
SET VERB
BIT
BITFIELD
NAME
DEFAULT
DESCRIPTION
7B0h
0
PD_
AUTOMUTE
0h
Auto-Mute Control:
0 = Automute disabled
1 = Automute enabled
Note: When PD_AUTOMUTE=1 and
Presence Detect (bit 31 in verb F09h)=1 the
WM8850 will replace the samples in the
stream with zeros
PGA1 (NID = 0Ah)
Table 7 gives a summary of the PGA1 node:
NODE SUMMARY INFORMATION
0Ch
NID
Widget Type
Audio Selector
Supported Get Verbs
Supported Set Verbs
Unsolicited Responses
Vendor-Specific Verbs
Bh, F00h, F02h, FB2h
3h, 7B2h, 7B3h
None
FB2h, 7B2h, 7B3h : PGA Control
Table 7 PGA1 Node Summary Information
PGA1 provides analogue gain for the inputs to Port-E, allowing the signal level to be adjusted by up to
+/-12dB in 0.5dB steps. Gain can be applied to left and right channels independently if required.
Additionally, a mute function is available – again this can be applied to separate channels as required.
The gain of PGA1 is controlled using the Amplifier Gain/Mute Verb.
Note: When Port-E is configured in single-ended mode the actual gain settings applied to the signal
will be adjusted by a further −3.0dB. This changes the effective gain range to −15dB to +9dB.
PP, April 2011, Rev 3.2
40
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
