MEMS Microphones Library

Diff: BSP/PDM2PCMAudio.h

Revision:

2:9f389fd8fb2e

Child:

6:9b8bc842aeb3

diff -r 245f83276546 -r 9f389fd8fb2e BSP/PDM2PCMAudio.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BSP/PDM2PCMAudio.h	Fri Apr 21 10:33:08 2017 +0200
@@ -0,0 +1,167 @@
+/**
+ ******************************************************************************
+ * @file    PDM2PCMAudio.h
+ * @author  AST / Software Platforms and Cloud
+ * @version V1.0
+ * @date    November 10th, 2016
+ * @brief   Class header file for the PDM2PCMAudio conversion library.
+ ******************************************************************************
+ * @attention
+ *
+ * <h2><center>&copy; COPYRIGHT(c) 2015 STMicroelectronics</center></h2>
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *   1. Redistributions of source code must retain the above copyright notice,
+ *      this list of conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright notice,
+ *      this list of conditions and the following disclaimer in the documentation
+ *      and/or other materials provided with the distribution.
+ *   3. Neither the name of STMicroelectronics nor the names of its contributors
+ *      may be used to endorse or promote products derived from this software
+ *      without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************
+ */
+
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+
+#ifndef __PDM2PCM_AUDIO_CLASS_H
+#define __PDM2PCM_AUDIO_CLASS_H
+
+
+/* Definitions ---------------------------------------------------------------*/
+
+#define USE_OPEN_PDM2PCM_LIBRARY
+#define PDM2PCM_AUDIO_DEBUG
+
+
+/* Includes ------------------------------------------------------------------*/
+
+#include "mbed.h"
+#include "component_def.h"
+#ifdef USE_OPEN_PDM2PCM_LIBRARY
+#include "OpenPDMFilter.h"
+#else
+#include "pdm_filter.h"
+#endif
+
+
+/* Definitions ---------------------------------------------------------------*/
+
+#define DEMUX_FILTER_SIZE         128
+#define DEMUX_FILTER_MASK         0x55
+#define PDM2PCM_FILTER_SIZE       4
+#define PDM2PCM_NOGAIN_VOLUME     4
+#define PDM2PCM_MAX_VOLUME        64
+#define PDM2PCM_DECIMATION_FACTOR 64
+
+
+/* Classes -------------------------------------------------------------------*/
+
+/** PDM2PCMAudio Conversion Library Class.
+ */
+class PDM2PCMAudio
+{
+public:
+
+    /**
+     * @brief Constructor.
+	 * @param  frequency Audio sampling frequency.
+	 * @param  channels  Number of audio channels to be recorded.
+     */
+    PDM2PCMAudio(uint32_t frequency, uint32_t channels) :
+	    _frequency(frequency),
+	    _channels(channels)
+#ifdef PDM2PCM_AUDIO_DEBUG
+	    , _pdm2pcm_audio_signal(D9)
+#endif
+    {
+	    /* Enable CRC peripheral to unlock the PDM2PCMAudio library. */
+	    __CRC_CLK_ENABLE();
+
+	    /* Initializing PDM2PCMAudio Filter. */
+	    for (uint32_t i = 0; i < _channels; i++)
+	    {
+#ifdef USE_OPEN_PDM2PCM_LIBRARY
+	        /* Filter LP and HP Init */
+	        _PDM2PCM_filter[i].LP_HZ = _frequency / 2;
+	        _PDM2PCM_filter[i].HP_HZ = 10;
+	        _PDM2PCM_filter[i].Fs = _frequency;
+	        _PDM2PCM_filter[i].Out_MicChannels = _channels;
+	        _PDM2PCM_filter[i].In_MicChannels = _channels;
+	        _PDM2PCM_filter[i].Decimation = 64;
+			_PDM2PCM_filter[i].SincN = 3;
+	        Open_PDM_Filter_Init((TPDMFilter_InitStruct *) &_PDM2PCM_filter[i]);
+#else
+	        /* Filter LP and HP Init */
+	        _PDM2PCM_filter[i].LP_HZ = _frequency / 2;
+	        _PDM2PCM_filter[i].HP_HZ = 10;
+	        _PDM2PCM_filter[i].Fs = _frequency;
+	        _PDM2PCM_filter[i].Out_MicChannels = _channels;
+	        _PDM2PCM_filter[i].In_MicChannels = _channels;
+	        PDM_Filter_Init((PDMFilter_InitStruct *) &_PDM2PCM_filter[i]);
+#endif
+	    }
+    };
+
+	/**
+	* @brief  Converting audio data from PDM to PCM.
+	* @param  output_buffer     Pointer to output PCM buffer data.
+	* @param  input_buffer      Pointer to input PDM buffer data.
+	* @param  volume            Volume level (it must be in the range [0..64]).
+	* @param  decimation_factor Decimation factor (it must be either 64 or 128).
+	* @retval COMPONENT_OK in case of success, COMPONENT_ERROR otherwise.
+	*/
+	status_t convert(int16_t *output_buffer, uint16_t *input_buffer, uint32_t volume, uint32_t decimation_factor);
+
+	/**
+	 * @brief  Scrambling audio data.
+	 * @param  output_buffer Pointer to output PDM buffer data.
+	 * @param  input_buffer  Pointer to input PDM buffer data.
+	 * @param  size          Size of the buffers (thay has to be equally sized).
+	 * @retval COMPONENT_OK in case of success, COMPONENT_ERROR otherwise.
+	 */
+	status_t scramble(uint16_t *output_buffer, uint16_t *input_buffer, uint32_t size);
+
+	/**
+	 * @brief  Demuxing audio data.
+	 * @param  output_buffer Pointer to output PDM buffer data.
+	 * @param  input_buffer  Pointer to input PDM buffer data.
+	 * @param  size          Size of the buffers (thay has to be equally sized).
+	 * @retval COMPONENT_OK in case of success, COMPONENT_ERROR otherwise.
+	 */
+	status_t demux(uint16_t *output_buffer, uint16_t *input_buffer, uint32_t size);
+
+
+protected:
+
+	uint32_t _frequency;
+	uint32_t _channels;
+#ifdef USE_OPEN_PDM2PCM_LIBRARY
+	TPDMFilter_InitStruct _PDM2PCM_filter[PDM2PCM_FILTER_SIZE];
+#else
+	PDMFilter_InitStruct _PDM2PCM_filter[PDM2PCM_FILTER_SIZE];
+#endif
+	static const uint8_t _demux_filter[DEMUX_FILTER_SIZE];
+
+#ifdef PDM2PCM_AUDIO_DEBUG
+	DigitalOut _pdm2pcm_audio_signal;
+#endif
+};
+
+#endif /* __PDM2PCM_AUDIO_CLASS_H */
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/