ST / X_NUCLEO_CCA02M1

Library to handle the X-NUCLEO-CCA02M1 MEMS Microphones Expansion Board.

Dependencies:   ST_I2S ST_FREQUENCY_DIVIDER USBDEVICE

Dependents:   HelloWorld_CCA02M1 HelloWorld_CCA02M1_mbedOS HelloWorld_CCA02M1 Karaoke_CCA01M1_CCA02M1_mbedOS

Fork of X_NUCLEO_CCA02M1 by ST Expansion SW Team

MEMS Microphones Library

Library to handle the X-NUCLEO-CCA02M1 MEMS Microphones Expansion Board. A single board allows to record a standard 2-channel stereo signal as an array of PCM samples (16 bit/sample); in principle, it could make use of six additional MEMS microphones to realize a 8-channel audio system.


Microphones configuration

Currently the configurations supported are the following:

  • Stereo@48KHz
  • Stereo@44.1KHz (CD audio quality)
  • Stereo@32KHz
  • Stereo@16KHz
  • Stereo@8KHz
  • Mono@48KHz
  • Mono@44.1KHz
  • Mono@32KHz
  • Mono@16KHz
  • Mono@8KHz

Mono configurations need a Jumper connecting PB_5 and PB_13 on the Morpho connector to properly work.


Platform compatibility

  • This board can be currently used with the Nucleo F4 Family only, please see the ST_I2S library compatibility for further information.
  • The library is compatible both with mbed OS 5.x and mbed classic 2.x (to work with mbed classic, the main application has to import the "events" library, which is not included into the "mbed" library).


I2S Peripheral Usage

By default this board makes use of the I2S peripheral available on Nucleo boards.


Acquiring through the USB

In order to acquire the recorded PCM audio channel with an audio SW on a PC, please connect the expansion board to a USB port of the PC, and the Nucleo board to a USB power supply.

Diff: Middlewares/OpenPDM2PCM/OpenPDMFilter.h

Revision:
20:9952bef19da1
Parent:
16:4ab2eac7be21
Child:
25:f2c04f757003
--- a/Middlewares/OpenPDM2PCM/OpenPDMFilter.h	Thu May 04 10:39:39 2017 +0000
+++ b/Middlewares/OpenPDM2PCM/OpenPDMFilter.h	Fri May 05 11:34:10 2017 +0000
@@ -44,28 +44,36 @@
 
 /* Definitions ---------------------------------------------------------------*/
 
-#define HTONS(A) ((((uint16_t)(A) & 0xff00) >> 8) | \
-                 (((uint16_t)(A) & 0x00ff) << 8))
-
-
 /*
  * Enable to use a Look-Up Table to improve performances while using more FLASH
  * and RAM memory.
+ * Note: Without Look-Up Table up to stereo@16KHz configuration is supported.
  */
 #define USE_LUT
 
+#define SINCN            3
+#define DECIMATION_MAX 128
+#define FILTER_GAIN     16
+
+#define HTONS(A) ((((uint16_t)(A) & 0xff00) >> 8) | \
+                 (((uint16_t)(A) & 0x00ff) << 8))
+#define RoundDiv(a, b)    (((a)>0)?(((a)+(b)/2)/(b)):(((a)-(b)/2)/(b)))
+#define SaturaLH(N, L, H) (((N)<(L))?(L):(((N)>(H))?(H):(N)))
+
 
 /* Types ---------------------------------------------------------------------*/
 
 typedef struct {
   /* Public */
-  uint16_t Fs;
   float LP_HZ;
   float HP_HZ;
-  uint16_t In_MicChannels;
-  uint16_t Out_MicChannels;
+  uint16_t Fs;
+  uint8_t In_MicChannels;
+  uint8_t Out_MicChannels;
+  uint8_t Decimation;
+  uint8_t MaxVolume;
   /* Private */
-  uint32_t Coef[5];
+  uint32_t Coef[SINCN];
   uint16_t FilterLen;
   int64_t OldOut, OldIn, OldZ;
   uint16_t LP_ALFA;
@@ -78,7 +86,8 @@
 /* Exported functions ------------------------------------------------------- */
 
 void Open_PDM_Filter_Init(TPDMFilter_InitStruct *init_struct);
-void Open_PDM_Filter(uint8_t* data, uint16_t* data_out, uint16_t mic_gain, TPDMFilter_InitStruct *init_struct);
+void Open_PDM_Filter_64(uint8_t* data, uint16_t* data_out, uint16_t mic_gain, TPDMFilter_InitStruct *init_struct);
+void Open_PDM_Filter_128(uint8_t* data, uint16_t* data_out, uint16_t mic_gain, TPDMFilter_InitStruct *init_struct);
 
 #ifdef __cplusplus
 }