1. Troy Davis Caitlin Smart
Step Counter Music DJ
Troy Davis
Caitlin Smart

2. Responsibilities Most of the development will be shared
Troy will responsible for interfacing the SD card as well as MP3 player system integration
Caitlin will be in charge of the accelerometer and updating song selection based on the runner’s pace

3. Motivation and Functionality
Have a song automatically selected for you that matches your jogging pace
Accelerometer to measure steps
MP3s from SD card
Provide all regular MP3 player functionality

4. Design
Decode MP3s from SD card and choose a song with similar BPM as joggers pace
Will have two tasks: one that polls accelerometer and one that plays MP3s
Audio codec & accelerometer interface via I²C

5. Reusable Design Elements
FPGA cores
I²C interface (via opencores.org)
WM8731 controller (via Altera)
C code
Drivers from I²C and WM8731 via their respective sources
Libraries
LIBMAD MPEG audio decoder library

6. Design Challenges
Getting the audio codec to send input from audio source to a speaker output
Decoding MP3s in real time

7. Code
// audio_ctrl.c #include "audio_ctrl.h" #include "io.h" #include <unistd.h> void i2c_write(unsigned char i2c_address, unsigned short data ); int audio_codec_write_ctrl( unsigned char reg_addr, unsigned short data ) { unsigned char first_byte, second_byte; unsigned short i2c_complete_data_word; // First byte contains the reg address and bit 8 of the data // This is a weird requirement of the audio codec chip first_byte = ( reg_addr << 1 ) | (( data >> 8 ) & 0x1 ); // Second byte contains bits 7:0 of the data second_byte = data & 0xFF; i2c_complete_data_// The address of the audio codec is always 0x1A // TODO: Make this a define. word = ( first_byte << 8 | second_byte ); i2c_write( AUDIO_CODEC_I2C_ADDRESS, i2c_complete_data_word ); return( 0 ); }

8. int audio_codec_init_i2c( alt_audio_codec* audio_codec )
{  
disable_audio_codec_controller( audio_codec );
reset_audio_codec_controller( audio_codec );
//  audio_codec_set_headphone_volume( audio_codec, 0 );
// Initialize the audio codec chip.
audio_codec_write_ctrl(AUDIO_CTRL_REG_RESET,0x000);  //RESET
audio_codec_write_ctrl( AUDIO_CTRL_REG_DIG_PATH_CTRL, 0x008 );  // Digital audio path: DAC soft mute on, De-emphasis off
audio_codec_write_ctrl( AUDIO_CTRL_REG_POWER_DOWN, 0x0E7 );  // power down control: CLKOUT-down, OSC-down, Mic-down, adc-down, line-in down
audio_codec_write_ctrl( AUDIO_CTRL_REG_IF_FORMAT, 0x003 );//slave mode and DSP mode
audio_codec_write_ctrl( AUDIO_CTRL_REG_ANG_PATH_CTRL, 0x0cb );  // sound select: sidetone ATT -15dB, sidetone off, DAC off, LineIn to ADC, by-pass on
audio_codec_write_ctrl( AUDIO_CTRL_REG_SAMPLING_CTRL, 0x023 );  // mclk: 44  kHz sampling  
audio_codec_write_ctrl( AUDIO_CTRL_REG_LINE_IN_L, 0x117 );  // L/R input    
audio_codec_write_ctrl( AUDIO_CTRL_REG_ACTIVE_CTRL,   0x001 );  // activate digital interface       
audio_codec_write_ctrl( AUDIO_CTRL_REG_POWER_DOWN, 0x067 );  // turn on power
audio_codec_write_ctrl( AUDIO_CTRL_REG_DIG_PATH_CTRL, 0x000 );  // unmute    
audio_codec_set_headphone_volume( audio_codec, audio_codec->headphone_volume );
enable_audio_codec_controller( audio_codec );
return( 0 ); }

9. int audio_codec_set_headphone_volume( alt_audio_codec
int audio_codec_set_headphone_volume( alt_audio_codec* audio_codec, int volume ) {
//char min = 0x2F;  //  47 unused
//char max = 0x7F;  //  127 unused
// default = 0x79 //
unsigned char r_volume_code, l_volume_code, l_pct, r_pct;
audio_codec->headphone_volume = volume;
// Calculate balance
if( audio_codec->headphone_balance <= 50 ){
l_pct = 100; 
} else {
l_pct = ( 50 - ( audio_codec->headphone_balance - 50 ) * 2); } 
if( audio_codec->headphone_balance >= 50 ){
r_pct = 100;
} else {
r_pct = ( audio_codec->headphone_balance * 2 ); }
l_volume_code = (((((( audio_codec->headphone_volume * l_pct ) / 100 ) * 80 ) / 100 ) + 48 ) - 1 );
r_volume_code = (((((( audio_codec->headphone_volume * r_pct ) / 100 ) * 80 ) / 100 ) + 48 ) - 1 );
audio_codec_write_ctrl( AUDIO_CTRL_REG_HEADPHONE_L, l_volume_code );
audio_codec_write_ctrl( AUDIO_CTRL_REG_HEADPHONE_R, r_volume_code );
return( 0 );

10. Test Plan Test units independently: Get sample BPM from jogging
Audio Codec through speaker output(Done!)
Accelerometer and measuring BPM
SD card
Get sample BPM from jogging
Shake accelerometer to see if music syncs

11. Optional Features Display track information on LCD Volume control
Move onto the small portable Altera board

12. Questions?