#define F_SAMPLE 48000.0f #define F_OUT 4000.0f #define PI 3.14159f   for(uint16_t i = 0; i < sample_N; i++) { sin = sinf(i * 2 * PI * sample_dt); dataI2S[i*2] = sin * 5000; dataI2S[i*2 + 1] =sin * 5000;   } HAL_I2S_Transmit_DMA(&hi...