DS4201

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102099

MIXER UNIT

The ADC Mixer Unit (MU) definition provides the mixer with capability to mix all input channels into all

output channels. In addition, mixing controls can be programmable or fixed. The MU descriptor reports

channel mixing, control capability, and input signal source information to the host. As with all ADC

audio units, the input pins and output pin of the MU connect to audio signal clusters; the clusters are

made up of logical channels which enter or exit the MU.

The DS4201 MU, MU:UID8, has 3 input clusters, each of which has 2 logical channels, and 1 output

cluster with 2 logical channels. Thus there are 6 logical inputs and 2 logical outputs. For this arrangement,

the ADC MU defines a mixing capability that consists of 12 controls (6 input channels x 2 output

channels). The MU descriptor field, bmControls, is used to indicate available programmable mixing

controls. The value for the bmControls field is built from a two dimensional array which contains a row

for each logical input channel and a column for each logical output channel. For a given array element,

bmControl[u,v], if [u,v] is set a programmable mixing control exists for input u to output v, if [u,v] is

clear the connection is non–programmable and its fixed value can be retrieved through a MU request.

The array corresponding to the DS4201 mixing capability is shown in Table 2.

For the DS4201, the array indicates the programmable mixing capability of left input channels with the

left out-put channel and likewise for right channels. The value for the bmControl field is built from the

values in Table 2 according to the method outlined in the ADC specification. For the DS4201 the field is

comprised of two bytes with values of: 0x99, 0x90.

bmCONTROL ARRAY FOR MU:UID8 Table 2

OUTPUT CHANNEL

INPUT CHANNEL

1

(OUT-L)

2

(OUT-R)

1 (DAC-L)

1

0

2 (DAC-R)

0

1

3 (AUX-L)

1

0

4 (AUX-R)

0

1

5 (MIC-L)

1

0

6 (MIC-R)

0

1

For programmable mixer controls, the ADC provides request commands to obtain the maximum and

minimum settings available for each control as well as control setting resolution. Programmable control

ranges and resolutions are shown in Table 3. MU commands are documented in APPENDIX A.