Shadowtrance
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <stdint.h>
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#include <stdbool.h>
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#include <tactility/error.h>
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#include <tactility/drivers/audio_codec.h>
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struct Device;
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief PDM MEMS microphone configuration.
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*
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* Covers any PDM mic with no I2C/register interface -- just I2S PDM RX -- e.g. SPM1423.
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* There is no I2C parent; the device sits standalone in the devicetree and only
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* references the I2S controller by name. PDM RX is hardware-restricted to I2S
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* controller 0 on ESP32 targets, so i2s_device must resolve to that controller.
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*/
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struct PdmMicConfig {
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/** I2S controller device that carries audio data */
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struct Device* i2s_device;
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/** Number of PDM mics wired (1 = mono, 2 = stereo) */
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uint8_t channels;
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/**
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* Fixed digital gain multiplier applied to this mic's samples by audio_stream, as an
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* integer percentage (100 = 1.0x / no boost, 400 = 4.0x). PDM mics have no hardware
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* gain control, so this is the only way to compensate for a capsule that's quiet at
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* the ADC's full-scale output. devicetree has no float property type, hence the
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* percent-scaled integer encoding. M5Stack's own SPM1423 reference firmware uses a
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* software multiplier of 4 (i.e. 400 here).
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*/
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uint16_t input_gain_percent;
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};
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#ifdef __cplusplus
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}
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#endif
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