I am using the STEVAL-STWINKT1B evaluation board to gather microphone data with a 192kHz sampling rate. The data is saved in a .dat file which i want to read and process. However, when reading the IMP23ABSU_MIC.dat file i get completely different results.
Using a freeware hex editor i opened the .dat file and this is how it looks:
As the samples are saved in a 16-bit integer (according to the mic's datasheet), which corresponds to 2 bytes, im expecting to read 0x31FF. This is valid since the HSDatalog software also presents the same value in int16 (e.g. -207). This is what i have tried so far in STM32CubeIDE:
DIR dir;
FILINFO fno;
FATFS uSDFatFs;
FIL MyFile;
UINT br;
FRESULT res;
char uSDPath[3] = "/";
static int16_t data_storage[48000] = { };
/* Working with ...\raw_data\192kHz\1bar (for evaluation)\phi_1_l_20*/
if (BSP_SD_Init() == MSD_OK) {
if (f_mount(&uSDFatFs, (TCHAR const*) uSDPath, 0) == FR_OK) {
res = f_opendir(&dir, uSDPath);
if (res == FR_OK) {
for (;;) {
res = f_readdir(&dir, &fno); /* Read a directory item */
if (res != FR_OK || fno.fname[0] == 0)
break; /* Error or end of dir */
if (fno.fattrib & AM_DIR) { /* Directory */
printf(" <DIR> %s\n", fno.fname);
} else { /* File */
printf("%10u %s\n", fno.fsize, fno.fname);
}
}
res = f_open(&MyFile, "STWIN_00001/IMP23ABSU_MIC.DAT", FA_READ);
if (res == FR_OK) {
res = f_read(&MyFile, data_storage, sizeof(data_storage),
&br);
static int16_t read_buff[100];
// f_gets(&read_buff, 100, &MyFile);
// unsigned char c = fgetc(&MyFile);
// int16_t c = fgetc(&MyFile);
char_t c = fgetc(&MyFile);
if (res == FR_OK) {
// Successfully read into data_storage
printf("Read %u bytes from the file.\n", br);
} else {
// Handle read error
}
f_close(&MyFile);
}
}
}
}
Both methods (using fgetc or f_read) for reading the file content provide different and wrong results
as
How can i read the content of the .dat file using Little Endian on this evaluation board with C?
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