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.

Middlewares/OpenPDM2PCM/OpenPDMFilter.c@11:b2f7f79026e4, 2017-04-28 (annotated)

Committer:
davide.aliprandi@st.com
Date:
Fri Apr 28 17:22:13 2017 +0200
Revision:
11:b2f7f79026e4
Parent:
6:9b8bc842aeb3
Child:
13:90465220b75f
OpenPDM2PCM library improved.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
davide.aliprandi@st.com 2:9f389fd8fb2e 1 /**
davide.aliprandi@st.com 2:9f389fd8fb2e 2 ******************************************************************************
davide.aliprandi@st.com 2:9f389fd8fb2e 3 * @file OpenPDMFilter.h
davide.aliprandi@st.com 2:9f389fd8fb2e 4 * @author CL
davide.aliprandi@st.com 2:9f389fd8fb2e 5 * @version V1.0.0
davide.aliprandi@st.com 2:9f389fd8fb2e 6 * @date 9-September-2015
davide.aliprandi@st.com 2:9f389fd8fb2e 7 * @brief Open PDM audio software decoding Library.
davide.aliprandi@st.com 2:9f389fd8fb2e 8 * This Library is used to decode and reconstruct the audio signal
davide.aliprandi@st.com 2:9f389fd8fb2e 9 * produced by ST MEMS microphone (MP45Dxxx, MP34Dxxx).
davide.aliprandi@st.com 2:9f389fd8fb2e 10 ******************************************************************************
davide.aliprandi@st.com 2:9f389fd8fb2e 11 * @attention
davide.aliprandi@st.com 2:9f389fd8fb2e 12 *
davide.aliprandi@st.com 2:9f389fd8fb2e 13 * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
davide.aliprandi@st.com 2:9f389fd8fb2e 14 *
davide.aliprandi@st.com 2:9f389fd8fb2e 15 * Licensed under MCD-ST Image SW License Agreement V2, (the "License");
davide.aliprandi@st.com 2:9f389fd8fb2e 16 * You may not use this file except in compliance with the License.
davide.aliprandi@st.com 2:9f389fd8fb2e 17 * You may obtain a copy of the License at:
davide.aliprandi@st.com 2:9f389fd8fb2e 18 *
davide.aliprandi@st.com 2:9f389fd8fb2e 19 * http://www.st.com/software_license_agreement_image_v2
davide.aliprandi@st.com 2:9f389fd8fb2e 20 *
davide.aliprandi@st.com 2:9f389fd8fb2e 21 * Unless required by applicable law or agreed to in writing, software
davide.aliprandi@st.com 2:9f389fd8fb2e 22 * distributed under the License is distributed on an "AS IS" BASIS,
davide.aliprandi@st.com 2:9f389fd8fb2e 23 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
davide.aliprandi@st.com 2:9f389fd8fb2e 24 * See the License for the specific language governing permissions and
davide.aliprandi@st.com 2:9f389fd8fb2e 25 * limitations under the License.
davide.aliprandi@st.com 2:9f389fd8fb2e 26 *
davide.aliprandi@st.com 2:9f389fd8fb2e 27 ******************************************************************************
davide.aliprandi@st.com 2:9f389fd8fb2e 28 */
davide.aliprandi@st.com 2:9f389fd8fb2e 29
davide.aliprandi@st.com 2:9f389fd8fb2e 30
davide.aliprandi@st.com 2:9f389fd8fb2e 31 /* Includes ------------------------------------------------------------------*/
davide.aliprandi@st.com 2:9f389fd8fb2e 32
davide.aliprandi@st.com 2:9f389fd8fb2e 33 #include "OpenPDMFilter.h"
davide.aliprandi@st.com 2:9f389fd8fb2e 34
davide.aliprandi@st.com 2:9f389fd8fb2e 35
davide.aliprandi@st.com 2:9f389fd8fb2e 36 /* Definitions ---------------------------------------------------------------*/
davide.aliprandi@st.com 2:9f389fd8fb2e 37
davide.aliprandi@st.com 2:9f389fd8fb2e 38 #define maxDecFactor 128
davide.aliprandi@st.com 2:9f389fd8fb2e 39 #define maxVol 64
davide.aliprandi@st.com 2:9f389fd8fb2e 40 #define FilterGain 16;
davide.aliprandi@st.com 2:9f389fd8fb2e 41 #define RoundDiv(a, b) (((a)>0)?(((a)+(b)/2)/(b)):(((a)-(b)/2)/(b)))
davide.aliprandi@st.com 2:9f389fd8fb2e 42 #define SaturaLH(N, L, H) (((N)<(L))?(L):(((N)>(H))?(H):(N)))
davide.aliprandi@st.com 2:9f389fd8fb2e 43
davide.aliprandi@st.com 2:9f389fd8fb2e 44
davide.aliprandi@st.com 2:9f389fd8fb2e 45 /* Variables -----------------------------------------------------------------*/
davide.aliprandi@st.com 2:9f389fd8fb2e 46
davide.aliprandi@st.com 2:9f389fd8fb2e 47 uint32_t coef[5][maxDecFactor]; // Max sinc 5 with decimation 128
davide.aliprandi@st.com 2:9f389fd8fb2e 48 uint32_t DivideConst = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 49 int64_t SubConst = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 50 uint32_t sinc1[maxDecFactor];
davide.aliprandi@st.com 2:9f389fd8fb2e 51 uint32_t sinc2[maxDecFactor*2];
davide.aliprandi@st.com 2:9f389fd8fb2e 52 uint32_t sinc3[maxDecFactor*3];
davide.aliprandi@st.com 2:9f389fd8fb2e 53 uint32_t sinc4[maxDecFactor*4];
davide.aliprandi@st.com 2:9f389fd8fb2e 54 uint32_t sinc[maxDecFactor*5];
davide.aliprandi@st.com 2:9f389fd8fb2e 55 int64_t Z = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 56 uint16_t app;
davide.aliprandi@st.com 2:9f389fd8fb2e 57
davide.aliprandi@st.com 2:9f389fd8fb2e 58
davide.aliprandi@st.com 2:9f389fd8fb2e 59 /* Functions -----------------------------------------------------------------*/
davide.aliprandi@st.com 2:9f389fd8fb2e 60
davide.aliprandi@st.com 11:b2f7f79026e4 61 int64_t filterTable(uint8_t *data, uint8_t table, uint8_t decimation, uint8_t channels);
davide.aliprandi@st.com 2:9f389fd8fb2e 62
davide.aliprandi@st.com 2:9f389fd8fb2e 63 void convolve(uint32_t Signal[/* SignalLen */], unsigned short SignalLen,
davide.aliprandi@st.com 2:9f389fd8fb2e 64 uint32_t Kernel[/* KernelLen */], unsigned short KernelLen,
davide.aliprandi@st.com 2:9f389fd8fb2e 65 uint32_t Result[/* SignalLen + KernelLen - 1 */]);
davide.aliprandi@st.com 2:9f389fd8fb2e 66
davide.aliprandi@st.com 11:b2f7f79026e4 67 inline int64_t filterTable(uint8_t *data, uint8_t table, uint8_t decimation, uint8_t channels)
davide.aliprandi@st.com 2:9f389fd8fb2e 68 {
davide.aliprandi@st.com 11:b2f7f79026e4 69 uint8_t c, i, j;
davide.aliprandi@st.com 11:b2f7f79026e4 70 uint16_t data_index = 0;
davide.aliprandi@st.com 11:b2f7f79026e4 71 uint32_t *coef_p = &coef[table][0];
davide.aliprandi@st.com 2:9f389fd8fb2e 72 int64_t F = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 73
davide.aliprandi@st.com 11:b2f7f79026e4 74 for (i = 0; i < decimation; i += 8)
davide.aliprandi@st.com 2:9f389fd8fb2e 75 {
davide.aliprandi@st.com 11:b2f7f79026e4 76 c = data[data_index];
davide.aliprandi@st.com 11:b2f7f79026e4 77 F += ((c >> 7) ) * coef_p[i ] +
davide.aliprandi@st.com 11:b2f7f79026e4 78 ((c >> 6) & 0x01) * coef_p[i + 1] +
davide.aliprandi@st.com 11:b2f7f79026e4 79 ((c >> 5) & 0x01) * coef_p[i + 2] +
davide.aliprandi@st.com 11:b2f7f79026e4 80 ((c >> 4) & 0x01) * coef_p[i + 3] +
davide.aliprandi@st.com 11:b2f7f79026e4 81 ((c >> 3) & 0x01) * coef_p[i + 4] +
davide.aliprandi@st.com 11:b2f7f79026e4 82 ((c >> 2) & 0x01) * coef_p[i + 5] +
davide.aliprandi@st.com 11:b2f7f79026e4 83 ((c >> 1) & 0x01) * coef_p[i + 6] +
davide.aliprandi@st.com 11:b2f7f79026e4 84 ((c ) & 0x01) * coef_p[i + 7];
davide.aliprandi@st.com 11:b2f7f79026e4 85 data_index += channels;
davide.aliprandi@st.com 2:9f389fd8fb2e 86 }
davide.aliprandi@st.com 2:9f389fd8fb2e 87 return F;
davide.aliprandi@st.com 2:9f389fd8fb2e 88 }
davide.aliprandi@st.com 2:9f389fd8fb2e 89
davide.aliprandi@st.com 2:9f389fd8fb2e 90 void Open_PDM_Filter_Init(TPDMFilter_InitStruct *Param)
davide.aliprandi@st.com 2:9f389fd8fb2e 91 {
davide.aliprandi@st.com 2:9f389fd8fb2e 92 uint16_t i,j;
davide.aliprandi@st.com 2:9f389fd8fb2e 93 int64_t sum = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 94 Param->Coef[0] = Param->Coef[1] = Param->Coef[2] = Param->Coef[3] = Param->Coef[4] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 95 for(i=0;i<5;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 96 {
davide.aliprandi@st.com 2:9f389fd8fb2e 97 Param->bit[i]=0;
davide.aliprandi@st.com 2:9f389fd8fb2e 98 }
davide.aliprandi@st.com 2:9f389fd8fb2e 99
davide.aliprandi@st.com 2:9f389fd8fb2e 100 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 101 {
davide.aliprandi@st.com 2:9f389fd8fb2e 102 sinc1[i]=1;
davide.aliprandi@st.com 2:9f389fd8fb2e 103 }
davide.aliprandi@st.com 2:9f389fd8fb2e 104 Param->OldOut = Param->OldIn = Param->OldZ = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 105 if(Param->LP_HZ!=0)
davide.aliprandi@st.com 2:9f389fd8fb2e 106 {
davide.aliprandi@st.com 2:9f389fd8fb2e 107 Param->LP_ALFA = (uint16_t)(Param->LP_HZ*256 / (Param->LP_HZ + Param->Fs/(2*3.14)));
davide.aliprandi@st.com 2:9f389fd8fb2e 108 }else
davide.aliprandi@st.com 2:9f389fd8fb2e 109 {
davide.aliprandi@st.com 2:9f389fd8fb2e 110 Param->LP_ALFA = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 111 }
davide.aliprandi@st.com 2:9f389fd8fb2e 112
davide.aliprandi@st.com 2:9f389fd8fb2e 113 if(Param->HP_HZ!=0)
davide.aliprandi@st.com 2:9f389fd8fb2e 114 {
davide.aliprandi@st.com 2:9f389fd8fb2e 115 Param->HP_ALFA = (uint16_t)(Param->Fs*256 / (2*3.14*Param->HP_HZ + Param->Fs));
davide.aliprandi@st.com 2:9f389fd8fb2e 116 }else
davide.aliprandi@st.com 2:9f389fd8fb2e 117 {
davide.aliprandi@st.com 2:9f389fd8fb2e 118 Param->HP_ALFA = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 119 }
davide.aliprandi@st.com 2:9f389fd8fb2e 120
davide.aliprandi@st.com 2:9f389fd8fb2e 121 switch(Param->SincN)
davide.aliprandi@st.com 2:9f389fd8fb2e 122 {
davide.aliprandi@st.com 2:9f389fd8fb2e 123 case 1:
davide.aliprandi@st.com 2:9f389fd8fb2e 124 Param->FilterLen = Param->Decimation;
davide.aliprandi@st.com 2:9f389fd8fb2e 125
davide.aliprandi@st.com 2:9f389fd8fb2e 126 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 127 {
davide.aliprandi@st.com 2:9f389fd8fb2e 128 coef[0][i]=1;
davide.aliprandi@st.com 2:9f389fd8fb2e 129 sum+= 1;
davide.aliprandi@st.com 2:9f389fd8fb2e 130 }
davide.aliprandi@st.com 2:9f389fd8fb2e 131 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 132 case 2:
davide.aliprandi@st.com 2:9f389fd8fb2e 133 Param->FilterLen = Param->Decimation * 2;
davide.aliprandi@st.com 2:9f389fd8fb2e 134
davide.aliprandi@st.com 2:9f389fd8fb2e 135 sinc[0] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 136
davide.aliprandi@st.com 2:9f389fd8fb2e 137 convolve(sinc1, Param->Decimation,sinc1,Param->Decimation,&sinc[1]);
davide.aliprandi@st.com 2:9f389fd8fb2e 138
davide.aliprandi@st.com 2:9f389fd8fb2e 139 for(j=0;j<2;j++)
davide.aliprandi@st.com 2:9f389fd8fb2e 140 {
davide.aliprandi@st.com 2:9f389fd8fb2e 141 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 142 {
davide.aliprandi@st.com 2:9f389fd8fb2e 143 coef[j][i] = sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 144 sum+= sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 145 }
davide.aliprandi@st.com 2:9f389fd8fb2e 146 }
davide.aliprandi@st.com 2:9f389fd8fb2e 147
davide.aliprandi@st.com 2:9f389fd8fb2e 148 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 149 case 3:
davide.aliprandi@st.com 2:9f389fd8fb2e 150 Param->FilterLen = Param->Decimation * 3;
davide.aliprandi@st.com 2:9f389fd8fb2e 151 sinc[0] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 152 sinc[Param->Decimation*3-1] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 153 convolve(sinc1, Param->Decimation,sinc1,Param->Decimation,sinc2);
davide.aliprandi@st.com 2:9f389fd8fb2e 154 convolve(sinc2, Param->Decimation*2-1,sinc1,Param->Decimation,&sinc[1]);
davide.aliprandi@st.com 2:9f389fd8fb2e 155 for(j=0;j<3;j++)
davide.aliprandi@st.com 2:9f389fd8fb2e 156 {
davide.aliprandi@st.com 2:9f389fd8fb2e 157 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 158 {
davide.aliprandi@st.com 2:9f389fd8fb2e 159 coef[j][i] = sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 160 sum+= sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 161 }
davide.aliprandi@st.com 2:9f389fd8fb2e 162 }
davide.aliprandi@st.com 2:9f389fd8fb2e 163 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 164 case 4:
davide.aliprandi@st.com 2:9f389fd8fb2e 165 Param->FilterLen = Param->Decimation * 4;
davide.aliprandi@st.com 2:9f389fd8fb2e 166 sinc[0] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 167 sinc[1] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 168 sinc[Param->Decimation*4-1] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 169 convolve(sinc1, Param->Decimation,sinc1,Param->Decimation,sinc2);
davide.aliprandi@st.com 2:9f389fd8fb2e 170 convolve(sinc2, Param->Decimation*2-1,sinc1,Param->Decimation,sinc3);
davide.aliprandi@st.com 2:9f389fd8fb2e 171 convolve(sinc3, Param->Decimation*3-2,sinc1,Param->Decimation,&sinc[2]);
davide.aliprandi@st.com 2:9f389fd8fb2e 172 for(j=0;j<4;j++)
davide.aliprandi@st.com 2:9f389fd8fb2e 173 {
davide.aliprandi@st.com 2:9f389fd8fb2e 174 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 175 {
davide.aliprandi@st.com 2:9f389fd8fb2e 176 coef[j][i] = sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 177 sum+= sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 178 }
davide.aliprandi@st.com 2:9f389fd8fb2e 179 }
davide.aliprandi@st.com 2:9f389fd8fb2e 180
davide.aliprandi@st.com 2:9f389fd8fb2e 181 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 182 case 5:
davide.aliprandi@st.com 2:9f389fd8fb2e 183 Param->FilterLen = Param->Decimation*5; // Dec * 5 - 2
davide.aliprandi@st.com 2:9f389fd8fb2e 184 sinc[0] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 185 sinc[1] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 186 sinc[Param->Decimation*5-2] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 187 sinc[Param->Decimation*5-1] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 188
davide.aliprandi@st.com 2:9f389fd8fb2e 189 convolve(sinc1, Param->Decimation,sinc1,Param->Decimation,sinc2);
davide.aliprandi@st.com 2:9f389fd8fb2e 190 convolve(sinc2, Param->Decimation*2-1,sinc1,Param->Decimation,sinc3);
davide.aliprandi@st.com 2:9f389fd8fb2e 191 convolve(sinc3, Param->Decimation*3-2,sinc1,Param->Decimation,sinc4);
davide.aliprandi@st.com 2:9f389fd8fb2e 192 convolve(sinc4, Param->Decimation*4-3,sinc1,Param->Decimation,&sinc[2]);
davide.aliprandi@st.com 2:9f389fd8fb2e 193
davide.aliprandi@st.com 2:9f389fd8fb2e 194 for(j=0;j<5;j++)
davide.aliprandi@st.com 2:9f389fd8fb2e 195 {
davide.aliprandi@st.com 2:9f389fd8fb2e 196 for(i=0;i<Param->Decimation;i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 197 {
davide.aliprandi@st.com 2:9f389fd8fb2e 198 coef[j][i] = sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 199 sum+= sinc[j*Param->Decimation+i];
davide.aliprandi@st.com 2:9f389fd8fb2e 200 }
davide.aliprandi@st.com 2:9f389fd8fb2e 201 }
davide.aliprandi@st.com 2:9f389fd8fb2e 202 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 203 }
davide.aliprandi@st.com 2:9f389fd8fb2e 204 SubConst = sum / 2;
davide.aliprandi@st.com 2:9f389fd8fb2e 205 DivideConst = SubConst*maxVol/32768/FilterGain;
davide.aliprandi@st.com 2:9f389fd8fb2e 206 if(DivideConst == 0 ) DivideConst = 1;
davide.aliprandi@st.com 2:9f389fd8fb2e 207 }
davide.aliprandi@st.com 2:9f389fd8fb2e 208
davide.aliprandi@st.com 2:9f389fd8fb2e 209 void convolve(uint32_t Signal[/* SignalLen */], unsigned short SignalLen,
davide.aliprandi@st.com 2:9f389fd8fb2e 210 uint32_t Kernel[/* KernelLen */], unsigned short KernelLen,
davide.aliprandi@st.com 2:9f389fd8fb2e 211 uint32_t Result[/* SignalLen + KernelLen - 1 */])
davide.aliprandi@st.com 2:9f389fd8fb2e 212 {
davide.aliprandi@st.com 2:9f389fd8fb2e 213 uint16_t n;
davide.aliprandi@st.com 2:9f389fd8fb2e 214 for (n = 0; n < SignalLen + KernelLen - 1; n++)
davide.aliprandi@st.com 2:9f389fd8fb2e 215 {
davide.aliprandi@st.com 2:9f389fd8fb2e 216 unsigned short kmin, kmax, k;
davide.aliprandi@st.com 2:9f389fd8fb2e 217
davide.aliprandi@st.com 2:9f389fd8fb2e 218 Result[n] = 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 219
davide.aliprandi@st.com 2:9f389fd8fb2e 220 kmin = (n >= KernelLen - 1) ? n - (KernelLen - 1) : 0;
davide.aliprandi@st.com 2:9f389fd8fb2e 221 kmax = (n < SignalLen - 1) ? n : SignalLen - 1;
davide.aliprandi@st.com 2:9f389fd8fb2e 222
davide.aliprandi@st.com 2:9f389fd8fb2e 223 for (k = kmin; k <= kmax; k++)
davide.aliprandi@st.com 2:9f389fd8fb2e 224 {
davide.aliprandi@st.com 2:9f389fd8fb2e 225 Result[n] += Signal[k] * Kernel[n - k];
davide.aliprandi@st.com 2:9f389fd8fb2e 226 }
davide.aliprandi@st.com 2:9f389fd8fb2e 227 }
davide.aliprandi@st.com 2:9f389fd8fb2e 228 }
davide.aliprandi@st.com 2:9f389fd8fb2e 229
davide.aliprandi@st.com 2:9f389fd8fb2e 230 void Open_PDM_Filter(uint8_t* data, uint16_t* dataOut, uint16_t MicGain, TPDMFilter_InitStruct *Param)
davide.aliprandi@st.com 2:9f389fd8fb2e 231 {
davide.aliprandi@st.com 2:9f389fd8fb2e 232 uint32_t i;
davide.aliprandi@st.com 2:9f389fd8fb2e 233 int64_t OldOut, OldIn, OldZ;
davide.aliprandi@st.com 2:9f389fd8fb2e 234 OldOut=Param->OldOut;
davide.aliprandi@st.com 2:9f389fd8fb2e 235 OldIn=Param->OldIn;
davide.aliprandi@st.com 2:9f389fd8fb2e 236 OldZ=Param->OldZ;
davide.aliprandi@st.com 2:9f389fd8fb2e 237
davide.aliprandi@st.com 2:9f389fd8fb2e 238 for (i = 0; i < Param->Fs/1000; i++)
davide.aliprandi@st.com 2:9f389fd8fb2e 239 {
davide.aliprandi@st.com 2:9f389fd8fb2e 240 switch(Param->SincN)
davide.aliprandi@st.com 2:9f389fd8fb2e 241 {
davide.aliprandi@st.com 2:9f389fd8fb2e 242 case 1:
davide.aliprandi@st.com 11:b2f7f79026e4 243 Z = filterTable(data, 0, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 244 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 245 case 2:
davide.aliprandi@st.com 11:b2f7f79026e4 246 Z = Param->Coef[0] + filterTable(data, 1, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 247 Param->Coef[0] = filterTable(data, 0, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 248 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 249 case 3:
davide.aliprandi@st.com 11:b2f7f79026e4 250 Z = Param->Coef[1] + filterTable(data, 2, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 251 Param->Coef[1] = Param->Coef[0] + filterTable(data, 1, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 252 Param->Coef[0] = filterTable(data, 0, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 253 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 254 case 4:
davide.aliprandi@st.com 11:b2f7f79026e4 255 Z = Param->Coef[2] + filterTable(data, 3, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 256 Param->Coef[2] = Param->Coef[1] + filterTable(data, 2, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 257 Param->Coef[1] = Param->Coef[0] + filterTable(data, 1, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 258 Param->Coef[0] = filterTable(data, 0, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 259 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 260 case 5:
davide.aliprandi@st.com 11:b2f7f79026e4 261 Z = Param->Coef[3] + filterTable(data, 4, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 262 Param->Coef[3] = Param->Coef[2] + filterTable(data, 3, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 263 Param->Coef[2] = Param->Coef[1] + filterTable(data, 2, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 264 Param->Coef[1] = Param->Coef[0] + filterTable(data, 1, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 11:b2f7f79026e4 265 Param->Coef[0] = filterTable(data, 0, Param->Decimation, Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 266 break;
davide.aliprandi@st.com 2:9f389fd8fb2e 267 }
davide.aliprandi@st.com 2:9f389fd8fb2e 268
davide.aliprandi@st.com 11:b2f7f79026e4 269 Z -= SubConst;
davide.aliprandi@st.com 2:9f389fd8fb2e 270
davide.aliprandi@st.com 11:b2f7f79026e4 271 if (Param->HP_ALFA!= 0)
davide.aliprandi@st.com 2:9f389fd8fb2e 272 {
davide.aliprandi@st.com 2:9f389fd8fb2e 273 OldOut = (Param->HP_ALFA * (OldOut + Z - OldIn))/256;
davide.aliprandi@st.com 11:b2f7f79026e4 274 OldIn = Z;
davide.aliprandi@st.com 11:b2f7f79026e4 275 Z = OldOut;
davide.aliprandi@st.com 2:9f389fd8fb2e 276 }
davide.aliprandi@st.com 2:9f389fd8fb2e 277
davide.aliprandi@st.com 11:b2f7f79026e4 278 if (Param->LP_ALFA != 0)
davide.aliprandi@st.com 2:9f389fd8fb2e 279 {
davide.aliprandi@st.com 2:9f389fd8fb2e 280 OldZ = ((256-Param->LP_ALFA)*OldZ+Param->LP_ALFA*Z)/256;
davide.aliprandi@st.com 2:9f389fd8fb2e 281 Z = OldZ;
davide.aliprandi@st.com 2:9f389fd8fb2e 282 }
davide.aliprandi@st.com 2:9f389fd8fb2e 283
davide.aliprandi@st.com 2:9f389fd8fb2e 284 // if(Param->SincN>=3){
davide.aliprandi@st.com 2:9f389fd8fb2e 285 // Z = RoundDiv(Z, DivideConst);
davide.aliprandi@st.com 2:9f389fd8fb2e 286 // Z *= MicGain;
davide.aliprandi@st.com 2:9f389fd8fb2e 287 // }else{
davide.aliprandi@st.com 2:9f389fd8fb2e 288 Z *= MicGain;
davide.aliprandi@st.com 2:9f389fd8fb2e 289 Z = RoundDiv(Z, DivideConst);
davide.aliprandi@st.com 2:9f389fd8fb2e 290 // }
davide.aliprandi@st.com 2:9f389fd8fb2e 291 Z = SaturaLH(Z, -32700, 32700); // saturation
davide.aliprandi@st.com 2:9f389fd8fb2e 292 dataOut[i*Param->Out_MicChannels] = Z ;
davide.aliprandi@st.com 11:b2f7f79026e4 293 data += ((Param->Decimation / 8) * Param->In_MicChannels);
davide.aliprandi@st.com 2:9f389fd8fb2e 294 }
davide.aliprandi@st.com 2:9f389fd8fb2e 295 Param->OldOut=OldOut;
davide.aliprandi@st.com 2:9f389fd8fb2e 296 Param->OldIn=OldIn;
davide.aliprandi@st.com 2:9f389fd8fb2e 297 Param->OldZ=OldZ;
davide.aliprandi@st.com 2:9f389fd8fb2e 298 }