# SNDEXIirFilterTarget

## Definition

  `#include <twl/snd.h>`

      typedef enum _SNDEXIirFilterTarget
      {
          SNDEX_IIR_FILTER_ADC_1 = 0,
          SNDEX_IIR_FILTER_ADC_2,
          SNDEX_IIR_FILTER_ADC_3,
          SNDEX_IIR_FILTER_ADC_4,
          SNDEX_IIR_FILTER_ADC_5,
          SNDEX_IIR_FILTER_DAC_LEFT_1,
          SNDEX_IIR_FILTER_DAC_LEFT_2,
          SNDEX_IIR_FILTER_DAC_LEFT_3,
          SNDEX_IIR_FILTER_DAC_LEFT_4,
          SNDEX_IIR_FILTER_DAC_LEFT_5,
          SNDEX_IIR_FILTER_DAC_RIGHT_1,
          SNDEX_IIR_FILTER_DAC_RIGHT_2,
          SNDEX_IIR_FILTER_DAC_RIGHT_3,
          SNDEX_IIR_FILTER_DAC_RIGHT_4,
          SNDEX_IIR_FILTER_DAC_RIGHT_5,
          SNDEX_IIR_FILTER_DAC_BOTH_1,
          SNDEX_IIR_FILTER_DAC_BOTH_2,
          SNDEX_IIR_FILTER_DAC_BOTH_3,
          SNDEX_IIR_FILTER_DAC_BOTH_4,
          SNDEX_IIR_FILTER_DAC_BOTH_5,
          SNDEX_IIR_FILTER_TARGET_MAX
      } SNDEXIirFilterTarget;

## Elements

SNDEX_IIR_FILTER_ADC_1 ... 5 | IIR filter for microphone input data (stage 1 - stage 5).
SNDEX_IIR_FILTER_DAC_LEFT_1 ... 5 | IIR filter for left speaker output data (stage 1 – stage 5).
SNDEX_IIR_FILTER_DAC_RIGHT_1 ... 5 | IIR filter for right speaker output data (stage 1 – stage 5).
SNDEX_IIR_FILTER_DAC_BOTH_1 ... 5 | IIR filter for both left and right speaker output data (stage 1 – stage 5).

## Description

This is an enumerated type that indicates the target to which IIR filters will be applied.

Filters are applied in ascending numerical order, as follows.

- (Microphone) -> A/D converter -> ADC1 -> ADC2 -> ADC3 -> ADC4 -> ADC5 -> Microphone input data
- Sound source -> DAC1 -> DAC2 -> DAC3 -> DAC4 -> DAC5 -> D/A converter -> (Speakers)

## See Also

`SNDEX_SetIirFilter, SNDEX_SetIirFilterAsync, SNDEXIirFilterParam`

## Revision History

2008/07/08 Initial version.

CONFIDENTIAL