Revision 0:dcefe9e5ec82, committed 2016-07-15

Comitter:

Mawrk

Date:

Fri Jul 15 14:11:14 2016 +0000

Commit message:

works

Changed in this revision

diff -r 000000000000 -r dcefe9e5ec82 BSP_DISCO_L476VG.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BSP_DISCO_L476VG.lib	Fri Jul 15 14:11:14 2016 +0000
@@ -0,0 +1,1 @@
+https://developer.mbed.org/teams/ST/code/BSP_DISCO_L476VG/#792b4cbebcb6

diff -r 000000000000 -r dcefe9e5ec82 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Jul 15 14:11:14 2016 +0000
@@ -0,0 +1,162 @@
+/*
+MICROPHONE RECORDER for the DISCOVERY STM32L476 dev board
+
+Records audio and sends it via UART as text-encoded samples
+sample rate: 25600 Hz
+sample format: 8bit signed (0-255)
+
+can record up to 31744 samples
+press the UP and DOWN keys to set the recording size
+press RIGHT to perform recording. The result is sent via UART after it is recorded
+
+
+you can deode the recording into a .wav file in matlab, by doing this:
+
+wavedata = wavedata - 128;
+wavedata = wavedata / 256;
+audiowrite('wave.wav', wavedata, 25600);
+
+
+*/
+
+
+#include "mbed.h"
+
+DigitalOut led_red(LED2);
+DigitalOut mic_clk(PE_9);
+DigitalIn mic_data(PE_7);
+
+InterruptIn right(JOYSTICK_RIGHT);
+InterruptIn up(JOYSTICK_UP);
+InterruptIn down(JOYSTICK_DOWN);
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+int recsize = 16384;
+
+void record() {
+    
+    unsigned int i;
+    uint8_t j;
+    uint8_t k;
+    
+    uint8_t *readouts;
+    volatile uint8_t sum;
+    volatile int readout;
+    uint16_t properSample;
+    
+    uint8_t integratingBuffer[7];
+    uint8_t bufferPointer = 6;
+    
+    readouts = (uint8_t*)malloc(recsize);
+    if (readouts == NULL){
+        pc.printf("FAILED TO ALLOCATE MEMORY!\n\r");
+        return;
+    }
+    
+    pc.printf("RECORDING!\n\r");
+             
+    //Step 1: pre-heat the microphone with 10ms+ of stable clocks
+    //otherwise the microphone returns GARBAGE (see datasheet)
+    for(i=0; i<80000; i++){
+        mic_clk = 0;
+        readout = mic_data; //fake smapling to keep the clock rythm
+        mic_clk = 1;
+    } 
+    
+    //Step 2: pre-fill the cyclyc integrating buffer
+    for(i=0; i<7; i++){
+        sum = 0;
+        for(j=0; j<32; j++){
+            mic_clk = 1;
+            readout = mic_data;
+            mic_clk = 0;
+            sum += readout;
+        }
+        bufferPointer = (bufferPointer+1)%7;
+        integratingBuffer[bufferPointer] = sum;
+    }
+   
+    //step 3: Actual sampling
+    led_red = 1;
+    for(i=0; i<recsize; i++){
+        //collect a 64x downsampled sample by summing the 1-bit input
+        sum = 0;
+        for(j=0; j<64; j++){
+            mic_clk = 1;
+            readout = mic_data;
+            mic_clk = 0;
+            sum += readout;
+        } 
+        
+        //push it into the cyclic integrating buffer
+        bufferPointer = (bufferPointer+1)%7;
+        integratingBuffer[bufferPointer] = sum;
+        
+        //sum the current content of the buffer to create one proper sample
+        properSample = 0;
+        for(k=0; k<7; k++){
+            properSample += integratingBuffer[k];
+        }
+        
+        //the sample taken 3 samples ago is counted TWICE, as the middle key sample
+        if(bufferPointer>=3){
+             properSample+=integratingBuffer[bufferPointer-3];
+        }else{
+             properSample+=integratingBuffer[bufferPointer+4];
+        }
+        
+        //proper sample is now a sum of 8 numbers from the range 0-64
+        //this can be up to 512, so we need to devide this by 2 to fit into 0-255
+        readouts[i] = (uint8_t)(properSample>>1);
+    }
+    led_red = 0;
+    mic_clk=1;
+    
+    //step 4: serial print
+     for(i=0; i<recsize; i++){
+       pc.printf("%u\n\r", readouts[i]);
+     }
+     
+    //step 5: clean
+    free(readouts);
+    pc.printf("DONE!\n\r");
+}
+
+void up_released() {
+    recsize+=1024;
+    pc.printf("recording size: %d\n\r", recsize);
+}
+
+
+void down_released() {
+     if(recsize>1024){
+        recsize-=1024;
+    }
+    pc.printf("recording size: %d\n\r", recsize);
+}
+
+void right_released() {
+    record();
+}
+
+int main()
+{
+    right.fall(&right_released);
+    up.fall(&up_released);
+    down.fall(&down_released);
+
+    right.mode(PullDown);
+    up.mode(PullDown);
+    down.mode(PullDown);
+
+
+    pc.baud(115200);    
+    pc.printf("booting\n\r");
+
+    
+    while(1){
+        ;
+    }   
+  
+}

diff -r 000000000000 -r dcefe9e5ec82 mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Fri Jul 15 14:11:14 2016 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/082adc85693f
\ No newline at end of file