Good morning everyone,
so here is my issue:
This image is showing the data saved on my micro sd card. As you all can see, 2 points are recorded correctly, 2 are incorrect and this pattern repeats itself throughout the file.
I thought maybe recording the I2S data into the buffer could be the issue.
Nope, everything looks good here.
So the source of my problem seems to be recording data from my buffer into the microSD card. How can I fix this?
The microSD card is in SPI (cannot change this, my PCB is designed this way). The I2S is setup in PCM, 24bit, 44100Hz, 1 channel.
Here is the code:
#include "Arduino.h"
#include "FS.h"
#include "Wav.h"
#include "I2S.h"
#include "SD.h"
#include "SPI.h"
//comment the first line and uncomment the second if you use ADC
#define I2S_MODE I2S_MODE_RX
//#define I2S_MODE I2S_MODE_ADC_BUILT_IN
const int record_time = 3; // second
const char filename[] = "/sound.wav"; //name of file created
const int headerSize = 44; //WAV header size
const int waveDataSize = record_time * 132000; //rough calculation seconds * Byte rate
const int numCommunicationData = 4096; //number of byte in buffer
const int numPartWavData = numCommunicationData/4; //number of int32 in buffer
byte header[headerSize]; //contains wav header
int communicationData[numPartWavData]; //was char before, now stores the values received by the ADC
//char partWavData[numPartWavData]; //relic of old code
size_t bytesRead; //number of bytes read
File file; //create file variable to write to
void setup() {
Serial.begin(115200); //initialize serial communication
if (!SD.begin()) Serial.println("SD begin failed"); //test if micro sd card is present and functionnal
//wait for sd card to connect
while(!SD.begin()){
Serial.print(".");
delay(500);
}
CreateWavHeader(header, waveDataSize); //create wav header in sd card
SD.remove(filename);
file = SD.open(filename, FILE_WRITE); //create file and set it up for write
if (!file) return;
file.write(header, headerSize); //write the wav header
I2S_Init(I2S_MODE, I2S_BITS_PER_SAMPLE_32BIT); //initialize the I2S
Serial.println("start recording");
//for loop ends once ther is enough data recorded to fit the amount of time desired
for (int j = 0; j < waveDataSize/numPartWavData; ++j) {
i2s_read(I2S_NUM_0, (char *)communicationData, numCommunicationData ,&bytesRead, portMAX_DELAY); //read ADC and put values in buffer
//ADC sends back signed 24bit value, need to bit shift since the wav file expects a signed int 32 bit
for (int i = 0; i < numPartWavData; i++)
{
communicationData[i] <<= 8;
}
//display buffer part of the buffer to verify the values
printf("[0]%d [1]%d [2]%d [3]%d \n", communicationData[0], communicationData[1], communicationData[2], communicationData[3]);
//both of these work but give out the same error
//Only half of the values are written properly.
//file.write((const byte*)communicationData, numCommunicationData);
file.print((char *)communicationData);
}
file.close();
Serial.println("finish");
}
void loop() {
}
