92HD87 Datasheet, PDF (16/204 Pages) Integrated Device Technology – SINGLE CHIP PC AUDIO SYSTEM

92HD87
SINGLE CHIP PC AUDIO SYSTEM, CODEC+STEREO SPEAKER AMPLIFIER+CAPLESS HP+LDO
When in 1.5V mode, the codec can correctly decode BITCLK, SYNC, RESET# and SDO as they
operate at 1.5V; additionally it will drive SDI and SDO at 1.5V. None of the GPIOs are affected, as
they always function at their nominal voltage (DVDD or AVDD).
2.11. Multi-channel capture
The capability to assign multiple “ADC Converters” to the same stream is supported to meet the
microphone array requirements of Vista and future operating systems. Single converter streams are
still supported this is done by assigning unique non zero Stream IDs to each converter. All capture
devices (ADCs 0 and 1) may be used to create a multi-channel input stream. There are no restric-
tions regarding digital microphones.
The ADC Converters can be associated with a single stream as long the sample rate and the bits per
sample are the same. The assignment of converter to channel is done using the “CnvtrID” widget
and is restricted to even values. The ADC converters will always put out a stereo sample and there-
fore require 2 channels per converter.
The stream will not be generated unless all entries for the targeted converters are set identically, and
the total number of assigned converter channels matches the value in the NmbrChan field. These
are listed the “Multi-Converter Stream Critical Entries.” table.
An example of a 4 Channel Steam with ADC0 supplying channels 0&1 and ADC1 supplying chan-
nels 2 & 3 is shown below. A 4 Channel stream can be created by assigning the same non-zero
stream id “Strm= N” to both ADC0 and ADC1. The sample rates must be set the same and the num-
ber of channels must be set to 4 channels “NmbrChan = 0011”.
ADC1 CnvtrID
ADC0 CnvtrID
(NID = 0x08)
[3:0]
(NID = 0x07)
[3:0]
Ch = 2
Ch=0
Table 4. Example channel mapping
Figure 1. Multi-channel capture
ADC0.CnvrtID.Channel = 0
ADC1.CnvrtID.Channel = 2
Stream ID
Data
Length
ADC0.CnvrtID.Channel = 2
ADC1.CnvrtID.Channel = 0
Stream ID
Data
Length
ADC0
Left Channel
ADC1
Left Channel
ADC0
Right Channel
ADC1
Right Channel
ADC1
Left Channel
ADC0
Left Channel
ADC1
Right Channel
ADC0
Right Channel
The following figure describes the bus waveform for a 24-bit, 48KHz capture stream with ID set to 1.
IDT CONFIDENTIAL
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V 0.995 01/11
92HD87