Appendices

Appendix A

Audio Code
/**************AUDIO CODE FOR MUSIC SYNTHESIZER *****************/
#include <Mega32.h> //the chip
#include <stdio.h> //for debugging using printf, etc
#include <Math.h> // for sine function

// definitions
#define begin {
#define end }

void initialize(void); //to set up ports
void chordsPlay(void);

//the following must not be registers
#pragma regalloc-
unsigned long increment,increment2 ;
unsigned char r_char; //received char
unsigned int i, j; //index to sineTable and counter for number of iterations in the assembly loop
unsigned char notes; //counter for number of notes played simultaneously
//flags for modulating the wave envelope
unsigned char modulate, brass, count, instrumentcount, instrumentshift;
unsigned char sineTable[256] @0x300; //Table of values; need location to avoid glitch
#pragma regalloc+

//**************************************************
void main(void)
begin
initialize();

//main loop never exits
while(1)
begin
chordsPlay(); //executes the pushbutton detection and music synthesis
end
end
//**********************************************************
void chordsPlay(void) //function that detects pushbuttons and activates the digital music synthesis
begin
if(brass==1){ //if the instrument requires waveform modulation
if(count<instrumentcount) count++; //increment counter when not yet time for modulation
else{
if(modulate>instrumentshift) modulate=modulate>>1; //shift in zeroes from the left
count=0; //reset counter
}
}
else modulate=0xff; //if the instrument does not require waveform modulation

notes=0; //reset counter for notes

if(PINC.7==0){ // 493.883 Hz
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 20715;//frequency*41.94304
}
}
if(PINC.6==0){ // 466.164 Hz---467
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 19552;//frequency*41.94304
}
else if(notes==1){//if one note played
notes=2; //two notes played
increment2 = 19552;//frequency*41.94304
}
}
if(PINC.5==0){ // 440 Hz --441
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 18455;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 18455;//frequency*41.94304
}
}
if(PINC.4==0){ // 415.305 Hz---416
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 17419;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 17419;//frequency*41.94304
}
}
f(PINC.3==0){ // 391.995 Hz ---390
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 16441;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 16441;//frequency*41.94304
}
}
if(PINC.2==0){ // 369.994 Hz ---370
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 15519;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 15519;//frequency*41.94304
}
}
if(PINC.1==0){ //349.228 Hz ---350
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 14648;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 14648;//frequency*41.94304
}
}
if(PINC.0==0){ // 329.628 Hz ---328
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment =13826;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 13826;//frequency*41.94304
}
}
if(PINB.7==0){ // 311.127 Hz --- 310
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 13050;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 13050;//frequency*41.94304
}
}
if(PINB.6==0){ //293.665 Hz --- 294
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 12317;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 12317;//frequency*41.94304
}
}
if(PINB.5==0){ //277.183 Hz --- 277
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 11626;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 11626;//frequency*41.94304
}
}
if(PINB.4==0){ //261.626 Hz --- 262
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 10973;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 10973;//frequency*41.94304
}
}
if(PINB.3==0){ //246.942 Hz --- 247
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 10357;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 10357;//frequency*41.94304
}
}
if(PINB.2==0){ //233.082 Hz --- 233
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 9776;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 9776;//frequency*41.94304
}
}
if(PINB.1==0){ //220 Hz --- 220
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 9227;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 9227;//frequency*41.94304
}
}
if(PINB.0==0){ //207.652 Hz --- 208
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 8710;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 8710;//frequency*41.94304
}
}
if(PIND.7==0){ //195.998 Hz --- 196
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 8221;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 8221;//frequency*41.94304
}
}
if(PIND.6==0){ //184.997 Hz --- 185
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 7759;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 7759;//frequency*41.94304
}
}
if(PIND.5==0){ // 174.614 Hz --- 175
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 7324;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 7324;//frequency*41.94304
}
}
if(PIND.4==0){ // 164.814 Hz --- 165
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 6913;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 6913;//frequency*41.94304
}
}
if(PIND.3==0){ // 146.832Hz --- 147
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 6159;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 6159;//frequency*41.94304
}
}
if(PIND.2==0){ // 130.813 Hz --- 131
if(notes==0){ //if no notes played yet
notes=1; //one note played
increment = 5487;//frequency*41.94304
}
else if(notes==1){ //if one note played
notes=2; //two notes played
increment2 = 5487;//frequency*41.94304
}
}

if(notes==1) increment2=0;
if(notes==0) modulate=0xff;

if(notes>0) //one or more notes played
begin
#asm
;load the increment bytes into registers
lds r9, _increment
lds r10,_increment+1
lds r11, _increment+2


;load the increment bytes into registers
lds r3, _increment2
lds r4,_increment2+1
lds r5, _increment2+2

;code with *** are responsible for modulating the waveform
lds r29, _modulate ;load the modulation flag into register ***

ldi R31, 0x3 ;high byte of Z is always pointing to start of the sineTable
lds r26,_j ;load int j into registers
lds r27,_j+1

Loop:
;40-cycle loop
add r12, r9 ;accumulator = accumulator + increment;
adc r13, r10 ;24-bit accumulator: r14 is highbyte1 (r14, r13, r12)
adc r14, r11 ;increment: r11 is highbyte1 (r11,r10,r9)
mov r30, r14 ;put highbyte1 into address Z
ld r2, Z ;2 cycles (load sineTable[highbyte1] at address Z to register 2)

add r6, r3 ;accumulator = accumulator + increment;
adc r7, r4 ;24-bit accumulator: r8 is highbyte (r8, r7, r6)
adc r8, r5 ;increment: r5 is highbyte2 (r5,r4,r3)
mov r30, r8 ;put highbyte2 into address Z
ld r15, Z ;2 cycles (load sineTable[highbyte2] at address Z to register 15)

add r15, r2 ;add the 2 contents together

sbrs r29, 0 ;skip if bit 0 is 0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 1 ;skip if bit 1 is 0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 2 ;skip if bit 2 is 0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 3 ;skip if bit 3=0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 4 ;skip if bit 4 =0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 5 ;skip if bit5=0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 6 ;skip if bit6=0 ***
lsr r15 ;shift right (/2) ***

sbrs r29, 7 ;skip if bit7=0 ***
lsr r15 ;shift right (/2)***

;PORTA = sineTable[highbyte1] + sineTable[highbyte2]
out 0x1B,r15

ldi r28, 0 ;put constants into registers
ldi r25, 1 ;put constants into registers
add r26, r25 ;j++;
adc r27, r28


cpi r26, low(0x07d0) ;1 cycle
ldi r28, high(0x07d0) ;1 cycle
cpc r27, r28 ;1 cycle
brsh EndLoop ;while(j<2000) ( 1 cycle if false)
rjmp Loop ;2 cycles else, repeat the loop

EndLoop:

#endasm

end


end
//*************************************************************************
interrupt [USART_RXC] void usart_rec(void) //implements the menu commands from the PC
begin
r_char=UDR; // get a char

switch(r_char){ //command depends on the representative char
case 'd': //default
brass=0;
for(i=0;i<256;i++) sineTable[i]=64+(char)(63.5*sin(6.283*((float)i)/256.0));
break;


//WOODWINDS

case 'c': //clarinet sound ....very good (clarinet and bass clarinet) ----------- DEMO
brass=0;
for(i=0;i<256;i++) sineTable[i]=64+(char)((19.01 *sin(6.283*((float)i)/256.0)) + (0.76 *sin(2*6.283*((float)i)/256.0))+ (18.82*sin(3*6.283*((float)i)/256.0)) + (2.28*sin(4*6.283*((float)i)/256.0)) + (10.08*sin(5*6.283*((float)i)/256.0)) + (2.09 *sin(6*6.283*((float)i)/256.0))+ (4.94*sin(7*6.283*((float)i)/256.0)) + (0.95 *sin(8*6.283*((float)i)/256.0))+(4.56*sin(9*6.283*((float)i)/256.0)));
break;

case 'f': //flute sound
brass=0;
for(i=0;i<256;i++) sineTable[i]=64+(char)((29.81 *sin(6.283*((float)i)/256.0)) + (23.95*sin(2*6.283*((float)i)/256.0)) + (5.37*sin(3*6.283*((float)i)/256.0)) + (3.28*sin(4*6.283*((float)i)/256.0)) + (1.49*sin(5*6.283*((float)i)/256.0)) + (0.596*sin(6*6.283*((float)i)/256.0)));
break;

case 'p': //piccolo
brass=0;
for(i=0;i<256;i++) sineTable[i]=64+(char)((29.81 *sin(2*6.283*((float)i)/256.0)) + (23.95*sin(4*6.283*((float)i)/256.0)) + (5.37*sin(6*6.283*((float)i)/256.0)) + (3.28*sin(8*6.283*((float)i)/256.0)) + (1.49*sin(10*6.283*((float)i)/256.0)) + (0.596*sin(12*6.283*((float)i)/256.0)));
break;

case 'o': //oboe sound
for(i=0;i<256;i++) sineTable[i]=64+(char)((3.01*sin(6.283*((float)i)/256.0)) + (11.14*sin(2*6.283*((float)i)/256.0))+ (10.08*sin(3*6.283*((float)i)/256.0)) + (17.33*sin(4*6.283*((float)i)/256.0)) + (9.905*sin(5*6.283*((float)i)/256.0)) + (6.72*sin(6*6.283*((float)i)/256.0))+ (3.36*sin(7*6.283*((float)i)/256.0))+ (0.0884*sin(8*6.283*((float)i)/256.0)) + (0.531*sin(9*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=40;
instrumentshift=0x7f;
break;


//BRASS

case 'h': //horn long sound (good for lower octave)
for(i=0;i<256;i++) sineTable[i]=64+(char)((24.8 *sin(6.283*((float)i)/256.0)) + (22.076*sin(2*6.283*((float)i)/256.0))+ (12.4*sin(3*6.283*((float)i)/256.0)) + (3.72*sin(4*6.283*((float)i)/256.0)) + (0.248*sin(5*6.283*((float)i)/256.0)) + (0.248*sin(8*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=50;
instrumentshift=0x7f;
break;

case 'i': //horn bounce sound (good for lower octave)
for(i=0;i<256;i++) sineTable[i]=64+(char)((24.8 *sin(6.283*((float)i)/256.0)) + (22.076*sin(2*6.283*((float)i)/256.0))+ (12.4*sin(3*6.283*((float)i)/256.0)) + (3.72*sin(4*6.283*((float)i)/256.0)) + (0.248*sin(5*6.283*((float)i)/256.0)) + (0.248*sin(8*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=30;
instrumentshift=0;
break;

case 't': //trombone long sound (good for lower octave) ----------- DEMO
for(i=0;i<256;i++) sineTable[i]=64+(char)((4.12*sin(6.283*((float)i)/256.0)) + (19.42*sin(2*6.283*((float)i)/256.0))+ (37.35*sin(3*6.283*((float)i)/256.0)) + (0.374*sin(4*6.283*((float)i)/256.0)) + (1.494*sin(5*6.283*((float)i)/256.0)) + (0.747*sin(6*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=45;
instrumentshift=0x7f;
break;

case 'u': //trombone bounce sound (good for lower octave) ----------- DEMO
for(i=0;i<256;i++) sineTable[i]=64+(char)((4.12*sin(6.283*((float)i)/256.0)) + (19.42*sin(2*6.283*((float)i)/256.0))+ (37.35*sin(3*6.283*((float)i)/256.0)) + (0.374*sin(4*6.283*((float)i)/256.0)) + (1.494*sin(5*6.283*((float)i)/256.0)) + (0.747*sin(6*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=30;
instrumentshift=0x0;
break;

case 'r': //trumpet long sound
for(i=0;i<256;i++) sineTable[i]=(char)(0.5*i);
brass=1;
instrumentcount=20;
instrumentshift=0x7f;
break;

case 's': //trumpet bouncesound
for(i=0;i<256;i++) sineTable[i]=(char)(0.5*i);
brass=1;
instrumentcount=20;
instrumentshift=0;
break;


//STRINGS

case 'z': //guitar (plucked string) ----------- DEMO
for(i=0;i<256;i++) sineTable[i]=64+(char)((4.12*sin(2*6.283*((float)i)/256.0)) + (20.1*sin(4*6.283*((float)i)/256.0))+ (37.35*sin(6*6.283*((float)i)/256.0)) + (0.374*sin(8*6.283*((float)i)/256.0)) + (1.494*sin(10*6.283*((float)i)/256.0)) );
brass=1;
instrumentcount=15;
instrumentshift=0;
break;

//PERCUSSION

case 'y': //steel drum
for(i=0;i<256;i++) sineTable[i]=64+(char)((sin(6.283*((float)i)/256.0)) + (19.42*sin(2*6.283*((float)i)/256.0))+ (37.35*sin(3*6.283*((float)i)/256.0)));
brass=1;
instrumentcount=8;
instrumentshift=0x0;
break;


}
end
//**********************************************************
//Set it all up
void initialize(void)
begin
UCSRB = 0x98 ;//enable RxC,Rx,Tx
UBRRL = 103 ; //using a 16 MHz crystal (9600)

//set up the ports
DDRD=0x00; // PORT D is an input with pullup
PORTD=0xff;
DDRB=0x00; // PORT B is an input with pullup
PORTB=0xff;
DDRC=0x00; // PORT C is an input with pullup
PORTC=0xff;

DDRA=0xff; // PORT A is an output
PORTA=0;

//make sine table
for(i=0;i<256;i++) sineTable[i]=64+(char)(63.5*sin(6.283*((float)i)/256.0));

//init the flags
increment = 0;
increment2=0;

notes=0;
j=1;
modulate=0xff;
brass=1;
count=0;
instrumentcount=0;
instrumentshift=0xff;

//crank up the ISRs
#asm
sei
clr r14
clr r13
clr r12
clr r6
clr r7