File content as of revision 21:4dbfda694c0d:

/**
  ******************************************************************************
  * @file    main.c
  * @author  Brian Mazzeo
  * @brief   This file provides a set of code for signal processing in 487.
  *          Parts are taken from example code from STMIcroelectronics
  ******************************************************************************
  * @attention
  *          This code was specifically developed for BYU ECEn 487 course 
  *          Introduction to Digital Signal Processing.
  *
  *
  ******************************************************************************
  */ 


#include "mbed.h"
#include "stm32746g_discovery_audio.h"
#include "stm32746g_discovery_sdram.h"
#include "stm32746g_discovery_lcd.h"

typedef enum {
    BUFFER_OFFSET_NONE = 0,
    BUFFER_OFFSET_HALF = 1,
    BUFFER_OFFSET_FULL = 2,
} BUFFER_StateTypeDef;

#define AUDIO_BLOCK_SAMPLES             ((uint32_t)128)         // Number of samples (L and R) in audio block (each samples is 16 bits)
#define AUDIO_BLOCK_SIZE                ((uint32_t)512)         // Number of bytes in audio block (4 * AUDIO_BLOCK_SAMPLES)

#define SDRAM_DEVICE_ADDR_AUDIO_MEM     ((uint32_t)0xC0400000)
#define AUDIO_BUFFER_IN                 SDRAM_DEVICE_ADDR_AUDIO_MEM
#define AUDIO_BUFFER_OUT                (AUDIO_BUFFER_IN + (AUDIO_BLOCK_SIZE * 2))

#define OSC_START_X_POS     20
#define OSC_LINE_SIZE       256
#define OSC_Y_POS           110
#define AUDIO_DRAW_LIMIT    30

Timer timer;

volatile uint32_t  audio_rec_buffer_state = BUFFER_OFFSET_NONE;
static void Erase_Trace(uint16_t Xpos, uint16_t Ypos, uint16_t Length);
static void Draw_Trace(uint16_t Xpos, uint16_t Ypos, uint16_t* Mem_start, uint16_t Length);
static void Audio_to_Float(uint16_t* buffer_in, float* L_out, float* R_out, uint16_t Length);
static void Float_to_Audio(float* L_in, float* R_in, uint16_t* buffer_out, uint16_t Length);

/* To do conversion to float */
float       L_channel_float[AUDIO_BLOCK_SAMPLES];
float       R_channel_float[AUDIO_BLOCK_SAMPLES];
float       *L_channel_float_p = &L_channel_float[0];
float       *R_channel_float_p = &R_channel_float[0];

/* Back conversion to integer */
uint16_t    Processed_audio[AUDIO_BLOCK_SAMPLES * 2];
uint16_t    *Processed_audio_p = &Processed_audio[0];

/* Useful variables during looping */
uint32_t counter = 0;
char buf[40];
int first_half_time = 0;
int second_half_time = 0;
int total_time = 0;

int main()
{
    /* Initialize the LCD Screen and display information */    
    BSP_LCD_Init();
    BSP_LCD_LayerDefaultInit(LTDC_ACTIVE_LAYER, LCD_FB_START_ADDRESS);
    BSP_LCD_SelectLayer(LTDC_ACTIVE_LAYER);

    BSP_LCD_Clear(LCD_COLOR_BLACK);
    BSP_LCD_SetFont(&LCD_DEFAULT_FONT);
        
    BSP_LCD_SetBackColor(LCD_COLOR_BLACK);
    BSP_LCD_SetTextColor(LCD_COLOR_ORANGE);
    BSP_LCD_DisplayStringAt(0, 0, (uint8_t *)"487 Mic Audio Test Code", LEFT_MODE);
    BSP_LCD_SetTextColor(LCD_COLOR_BLUE);
    BSP_LCD_DisplayStringAt(0, OSC_Y_POS - 20, (uint8_t *)"L", LEFT_MODE);
    BSP_LCD_SetTextColor(LCD_COLOR_GREEN);
    BSP_LCD_DisplayStringAt(0, OSC_Y_POS, (uint8_t *)"R", LEFT_MODE);


    /* Initialize the Audio Interface */
    BSP_AUDIO_IN_OUT_Init(INPUT_DEVICE_DIGITAL_MICROPHONE_2, OUTPUT_DEVICE_HEADPHONE, DEFAULT_AUDIO_IN_FREQ, DEFAULT_AUDIO_IN_BIT_RESOLUTION, DEFAULT_AUDIO_IN_CHANNEL_NBR);

    /* Initialize SDRAM buffers */
    BSP_SDRAM_Init();
    memset((uint16_t *)AUDIO_BUFFER_IN, 0, AUDIO_BLOCK_SIZE * 2);
    memset((uint16_t *)AUDIO_BUFFER_OUT, 0, AUDIO_BLOCK_SIZE * 2);


    /* Start Recording */
    if (BSP_AUDIO_IN_Record((uint16_t *)AUDIO_BUFFER_IN, AUDIO_BLOCK_SIZE) != AUDIO_OK) { printf("BSP_AUDIO_IN_Record error\n"); }

    /* Start Playback */
    BSP_AUDIO_OUT_SetAudioFrameSlot(CODEC_AUDIOFRAME_SLOT_02);
    if (BSP_AUDIO_OUT_Play((uint16_t *)AUDIO_BUFFER_OUT, AUDIO_BLOCK_SIZE * 2) != AUDIO_OK) { printf("BSP_AUDIO_OUT_Play error\n"); }


    timer.start();
    while (1) {
    /* First Half */
        /* Wait end of half block recording before going on in the first half cycle*/
        while (audio_rec_buffer_state != BUFFER_OFFSET_HALF) {}

        /* This captures the time of an entire cycle */
        total_time = timer.read_us();
        
        /* Reset the timer counter to zero */
        timer.reset();

        /* Plot traces of first half block recording */   
        Erase_Trace(OSC_START_X_POS, OSC_Y_POS, AUDIO_BLOCK_SAMPLES);
        Draw_Trace(OSC_START_X_POS, OSC_Y_POS, (uint16_t *) AUDIO_BUFFER_IN, AUDIO_BLOCK_SAMPLES);
        
        /* Convert data to floating point representation for processing */
        Audio_to_Float((uint16_t *) AUDIO_BUFFER_IN, L_channel_float_p, R_channel_float_p, AUDIO_BLOCK_SAMPLES);
        
        sprintf(buf, "Lf[0]:%8.1f Ai[0]:%6d ", L_channel_float[0], ((int16_t) *((uint16_t *) AUDIO_BUFFER_IN)));
        BSP_LCD_DisplayStringAt(0, 150, (uint8_t *) buf, LEFT_MODE);
                
        Float_to_Audio(L_channel_float_p, R_channel_float_p, (uint16_t *) Processed_audio, AUDIO_BLOCK_SAMPLES);

        /* Copy recorded 1st half block into the audio buffer that goes out */
        //memcpy((uint16_t *)(AUDIO_BUFFER_OUT), (uint16_t *)(AUDIO_BUFFER_IN), AUDIO_BLOCK_SIZE);
        memcpy((uint16_t *)(AUDIO_BUFFER_OUT), (uint16_t *)(Processed_audio), AUDIO_BLOCK_SIZE);

        /* Capture the timing of the first half processing */
        first_half_time = timer.read_us();
    /* End First Half */

    /* Second Half */
        /* Wait end of one block recording */
        while (audio_rec_buffer_state != BUFFER_OFFSET_FULL) {}
        
        /* Plot traces of second half block recording */
        Erase_Trace(OSC_START_X_POS+AUDIO_BLOCK_SAMPLES, OSC_Y_POS, AUDIO_BLOCK_SAMPLES);
        Draw_Trace( OSC_START_X_POS+AUDIO_BLOCK_SAMPLES, OSC_Y_POS, (uint16_t *) (AUDIO_BUFFER_IN + (AUDIO_BLOCK_SIZE)), AUDIO_BLOCK_SAMPLES);
                
        /* Compute important cycle information and display it*/
        counter++;
        sprintf(buf, "Cycles: %9d", counter);
        BSP_LCD_SetTextColor(LCD_COLOR_RED);
        BSP_LCD_DisplayStringAt(0, 46, (uint8_t *) buf, LEFT_MODE);                
        sprintf(buf, "1:%6d 2:%6d T:%6d", first_half_time, second_half_time, total_time);
        BSP_LCD_DisplayStringAt(0, 20, (uint8_t *) buf, LEFT_MODE);

        /* Copy recorded 2nd half block into audio output buffer */
        memcpy((uint16_t *)(AUDIO_BUFFER_OUT + (AUDIO_BLOCK_SIZE)), (uint16_t *)(AUDIO_BUFFER_IN + (AUDIO_BLOCK_SIZE)), AUDIO_BLOCK_SIZE);
            
        /* Change the recording buffer state to reflect the status of the buffer */   
        audio_rec_buffer_state = BUFFER_OFFSET_NONE;
        
        /* Measures the amount of time to process the second half */    
        second_half_time = timer.read_us();
        
    /* End Second Half */
    }
}

/**
  * @brief  Draws a trace of the data line.
  * @param  Xpos: X position
  * @param  L_Ypos: Left channel Y position
  * @param  R_Ypos: Right channel Y position
  * @param  Mem_start: Start of memory location
  * @param  Length: length of trace
  * @retval None
  */
void Erase_Trace(uint16_t Xpos, uint16_t Ypos, uint16_t Length)
{
    BSP_LCD_SetTextColor(LCD_COLOR_BROWN);
    BSP_LCD_FillRect(Xpos, Ypos - AUDIO_DRAW_LIMIT, Length, AUDIO_DRAW_LIMIT);
    BSP_LCD_FillRect(Xpos, Ypos+1, Length, AUDIO_DRAW_LIMIT);
    
    BSP_LCD_SetTextColor(LCD_COLOR_WHITE);
    BSP_LCD_DrawHLine(Xpos, Ypos, Length);

}


/**
  * @brief  Draws a trace of the data line.
  * @param  Xpos: X position
  * @param  L_Ypos: Left channel Y position
  * @param  R_Ypos: Right channel Y position
  * @param  Mem_start: Start of memory location
  * @param  Length: length of trace
  * @retval None
  */
void Draw_Trace(uint16_t Xpos, uint16_t Ypos, uint16_t* Mem_start, uint16_t Length)
{
    uint16_t i;
    uint16_t* mem_address;
    char buf[10];
    int16_t L_audio_value;
    int16_t R_audio_value;
       
    mem_address = Mem_start;
      
    for (i=0; i<Length; i++)
   {       
        L_audio_value = (int16_t) *mem_address;
        mem_address++;
        R_audio_value = (int16_t) *mem_address;
        mem_address++;
        
        L_audio_value = L_audio_value / 100;
        R_audio_value = R_audio_value / 100;
        
        if (L_audio_value > AUDIO_DRAW_LIMIT) {L_audio_value = AUDIO_DRAW_LIMIT;}
        else if (L_audio_value < -AUDIO_DRAW_LIMIT) {L_audio_value = -AUDIO_DRAW_LIMIT;}

        if (R_audio_value > AUDIO_DRAW_LIMIT) {R_audio_value = AUDIO_DRAW_LIMIT;}
        else if (R_audio_value < -AUDIO_DRAW_LIMIT) {R_audio_value = -AUDIO_DRAW_LIMIT;}
        
        BSP_LCD_DrawPixel(Xpos + i, (uint16_t) ((int16_t) Ypos + L_audio_value), LCD_COLOR_BLUE);
        BSP_LCD_DrawPixel(Xpos + i, (uint16_t) ((int16_t) Ypos + R_audio_value), LCD_COLOR_GREEN);
   }
   
}

/**
  * @brief  Converts audio data in buffer to floating point representation.
  * @param  buffer_in: Pointer to Audio buffer start location
  * @param  L_out: Pointer to Left channel out data (float)
  * @param  R_out: Pointer to Right channel out data (float)
  * @param  Length: length of data to convert
  * @retval None
  */
void Audio_to_Float(uint16_t* buffer_in, float* L_out, float* R_out, uint16_t Length)
{
    uint16_t i;
    uint16_t* audio_mem_address;
    float* L_chan_mem_address;
    float* R_chan_mem_address;
    float L_audio_value;
    float R_audio_value;

    audio_mem_address = buffer_in;
    L_chan_mem_address = L_out;
    R_chan_mem_address = R_out;
    
    for (i=0; i<Length; i++)
   {
        L_audio_value = (float) ((int16_t) *audio_mem_address);
        audio_mem_address++;
        R_audio_value = (float) ((int16_t) *audio_mem_address);
        audio_mem_address++;
                
        *L_chan_mem_address = L_audio_value;
        L_chan_mem_address++;
        
        *R_chan_mem_address = R_audio_value;
        R_chan_mem_address++;
   }
}

/**
  * @brief  Converts audio data in buffer to floating point representation.
  * @param  L_out: Pointer to Left channel in data (float)
  * @param  R_out: Pointer to Right channel in data (float)
  * @param  buffer_out: Pointer to combined 32 bit (two 16-bit int samples)
  * @param  Length: length of data to convert
  * @retval None
  */
void Float_to_Audio(float* L_in, float* R_in, uint16_t* buffer_out, uint16_t Length)
{
    uint16_t i;
    uint16_t* audio_mem_address;
    float* L_chan_mem_address;
    float* R_chan_mem_address;
    int16_t L_audio_value;
    int16_t R_audio_value;
        
    audio_mem_address = buffer_out;
    L_chan_mem_address = L_in;
    R_chan_mem_address = R_in;
    
    for (i=0; i<Length; i++)
   {
        L_audio_value = (int16_t) ((float) *L_chan_mem_address);
        L_chan_mem_address++;
        
        R_audio_value = (int16_t) ((float) *R_chan_mem_address);
        R_chan_mem_address++;
        
        *audio_mem_address = (uint16_t) L_audio_value;
        audio_mem_address++;
        *audio_mem_address = (uint16_t) R_audio_value;
        audio_mem_address++;
   }
}





/*-------------------------------------------------------------------------------------
       Callbacks implementation:
           the callbacks API are defined __weak in the stm32746g_discovery_audio.c file
           and their implementation should be done in the user code if they are needed.
           Below some examples of callback implementations.
  -------------------------------------------------------------------------------------*/
/**
  * @brief Manages the DMA Transfer complete interrupt.
  * @param None
  * @retval None
  */
void BSP_AUDIO_IN_TransferComplete_CallBack(void)
{
    audio_rec_buffer_state = BUFFER_OFFSET_FULL;
}

/**
  * @brief  Manages the DMA Half Transfer complete interrupt.
  * @param  None
  * @retval None
  */
void BSP_AUDIO_IN_HalfTransfer_CallBack(void)
{
    audio_rec_buffer_state = BUFFER_OFFSET_HALF;
}

/**
  * @brief  Audio IN Error callback function.
  * @param  None
  * @retval None
  */
void BSP_AUDIO_IN_Error_CallBack(void)
{
    printf("BSP_AUDIO_IN_Error_CallBack\n");
}