#device PIC16F688, ADC=8																															// Spectrum Analyzer & Scope	Aug, 2008
#fuses	hs,mclr,put,noprotect,nocpd,nobrownout,nowdt,nofcmen,noieso  									// nothing special needed here
#use	delay(clock=20000000)																														// compilerspecific delays for 8MHz
struct{int1 e:1;int1 rs:1;int x:4;}d;																									// C0=E,C1=RS,C2-C5=D5-D9,4bit,Single Line
#byte d=0x07																																					// span struct over port
const int font[256]={																																	// fonttable, 8 symbols skipped(max array size)
0b00000000,0b00011100,0b00100010,0b01000001,0b00000000,/* ( */ 0b00000000,0b01000001,0b00100010,0b00011100,0b00000000,/* ) */
0b00010100,0b00001000,0b00111110,0b00001000,0b00010100,/* * */ 0b00001000,0b00001000,0b00111110,0b00001000,0b00001000,/* + */
0b00000000,0b00000101,0b00000110,0b00000000,0b00000000,/* , */ 0b00001000,0b00001000,0b00001000,0b00001000,0b00001000,/* - */
0b00000000,0b00000011,0b00000011,0b00000000,0b00000000,/* . */ 0b00000010,0b00000100,0b00001000,0b00010000,0b00100000,/* / */
0b00111110,0b01000101,0b01001001,0b01010001,0b00111110,/* 0 */ 0b00000001,0b00100001,0b01111111,0b00000001,0b00000001,/* 1 */
0b00100001,0b01000011,0b01000101,0b01001001,0b00110001,/* 2 */ 0b01000010,0b01000001,0b01010001,0b01101001,0b01000110,/* 3 */
0b00001100,0b00010100,0b00100100,0b01111111,0b00000100,/* 4 */ 0b01110010,0b01010001,0b01010001,0b01010001,0b01001110,/* 5 */
0b00011110,0b00101001,0b01001001,0b01001001,0b00000110,/* 6 */ 0b01000000,0b01000111,0b01001000,0b01010000,0b01100000,/* 7 */
0b00110110,0b01001001,0b01001001,0b01001001,0b00110110,/* 8 */ 0b00110000,0b01001001,0b01001001,0b01001010,0b00111100,/* 9 */
0b00000000,0b00110110,0b00110110,0b00000000,0b00000000,/* : */ 0b00000000,0b00110101,0b00110110,0b00000000,0b00000000,/* ; */
0b00001000,0b00010100,0b00100010,0b01000001,0b00000000,/* < */ 0b00010100,0b00010100,0b00010100,0b00010100,0b00010100,/* = */
0b00000000,0b01000001,0b00100010,0b00010100,0b00001000,/* > */ 0b00100000,0b01000000,0b01000101,0b01001000,0b00110000,/* ? */
0b00100110,0b01001001,0b01001111,0b01000001,0b00111110,/* @ */ 0b00111111,0b01000100,0b01000100,0b01000100,0b00111111,/* A */
0b01111111,0b01001001,0b01001001,0b01001001,0b00110110,/* B */ 0b00111110,0b01000001,0b01000001,0b01000001,0b00100010,/* C */
0b01111111,0b01000001,0b01000001,0b00100010,0b00011100,/* D */ 0b01111111,0b01001001,0b01001001,0b01001001,0b01000001,/* E */
0b01111111,0b01001000,0b01001000,0b01001000,0b01000000,/* F */ 0b00111110,0b01000001,0b01001001,0b01001001,0b00101111,/* G */
0b01111111,0b00001000,0b00001000,0b00001000,0b01111111,/* H */ 0b01000001,0b01000001,0b01111111,0b01000001,0b01000001,/* I */
0b00000010,0b00000001,0b01000001,0b01111110,0b01000000,/* J */ 0b01111111,0b00001000,0b00010100,0b00100010,0b01000001,/* K */
0b01111111,0b00000001,0b00000001,0b00000001,0b00000001,/* L */ 0b01111111,0b00100000,0b00011000,0b00100000,0b01111111,/* M */
0b01111111,0b00010000,0b00001000,0b00000100,0b01111111,/* N */ 0b00111110,0b01000001,0b01000001,0b01000001,0b00111110,/* O */
0b01111111,0b01001000,0b01001000,0b01001000,0b00110000,/* P */ 0b00111110,0b01000001,0b01000101,0b01000010,0b00111101,/* Q */
0b01111111,0b01001000,0b01001100,0b01001010,0b00110001,/* R */ 0b00110001,0b01001001,0b01001001,0b01001001,0b01000110,/* S */
0b01000000,0b01000000,0b01111111,0b01000000,0b01000000,/* T */ 0b01111110,0b00000001,0b00000001,0b00000001,0b01111110,/* U */
0b01111100,0b00000010,0b00000001,0b00000010,0b01111100,/* V */ 0b01111110,0b00000001,0b00001110,0b00000001,0b01111110,/* W */
0b01100011,0b00010100,0b00001000,0b00010100,0b01100011,/* X */ 0b01110000,0b00001000,0b00000111,0b00001000,0b01110000,/* Y */
0b01000011,0b01000101,0b01001001,0b01010001,0b01100001};/* Z */	
const signed int mul[16][16]={49,42,35,28,21,14,7,0,-7,-14,-21,-28,-35,-42,-49,-56,42,36,30,24,18,12,6,0,-6,-12,-18,-24,-30,
-36,-42,-48,35,30,25,20,15,10,5,0,-5,-10,-15,-20,-25,-30,-35,-40,28,24,20,16,12,8,4,0,-4,-8,-12,-16,-20,-24,-28,-32,21,18,15,
12,9,6,3,0,-3,-6,-9,-12,-15,-18,-21,-24,14,12,10,8,6,4,2,0,-2,-4,-6,-8,-10,-12,-14,-16,7,6,5,4,3,2,1,0,-1,-2,-3,-4,-5,-6,-7,
-8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,-14,-12,-10,-8,-6,-4,-2,0,2,4,6,8,10,12,14,16,-21,
-18,-15,-12,-9,-6,-3,0,3,6,9,12,15,18,21,24,-28,-24,-20,-16,-12,-8,-4,0,4,8,12,16,20,24,28,32,-35,-30,-25,-20,-15,-10,-5,0,5,
10,15,20,25,30,35,40,-42,-36,-30,-24,-18,-12,-6,0,6,12,18,24,30,36,42,48,-49,-42,-35,-28,-21,-14,-7,0,7,14,21,28,35,42,49,56,
-56,-48,-40,-32,-24,-16,-8,0,8,16,24,32,40,48,56,64};
const int sin[64]={8,8,9,10,11,11,12,13,13,14,14,15,15,15,15,15,15,15,15,15,15,15,14,14,13,13,12,11,11,10,9,8,8,7,6,5,4,4,3,
2,2,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1,2,2,3,4,4,5,6,7};
const int cos[64]={15,15,15,15,15,15,14,14,13,13,12,11,11,10,9,8,8,7,6,5,4,4,3,2,2,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1,2,2,3,4,4,5,
6,7,7,8,9,10,11,11,12,13,13,14,14,15,15,15,15,15};
//const int log[16]={1,2,3,4,5,6,7,8,9,10,11,13,15,18,23,32};
const int log[16]={0,1,2,3,4,5,6,7,8,9,10,11,13,16,23,32};
volatile int i,mode,buf[40];	

#int_ra																																								// button press interrupt entry point
void button_isr(){int p;if(mode==3)mode=0; else mode++;for(p=0;p<200;p++)while(!input(41));} // wtf debounce,  toggle modi, 

void dnib(int n){d.x=n;delay_cycles(1);d.e=1;delay_us(6);d.e=0;}											// neat lcd driver
void dbyt(int r,n){d.rs=d.e=0;delay_us(38);d.rs=r;dnib(n>>4);dnib(n&15);}							// min delay may vary with lcd
void dput(int c){dbyt(1,c);}

void graph(int pen){int col,line,block=0,c=0;																					// draw graphic blocks
	for(dbyt(0,64);block<39;block+=5,c+=2,dbyt(1,i)){																		// set LcdCGram-start, cycle trough lcdblocks
		for(line=7;line-->0;dbyt(1,i)){																										// write bytes to dislay
			if(pen==0){for(col=0;col<5;(i<<=1)+=bit_test(buf[col++ +block],line));}					// create patterns by crosscomparing columns with linecounter 			
			if(pen==1){for(col=0;col<5;(i<<=1)+=(line==((buf[col++ +block]))));}						// decimalcompare line+buf &shift hits to CGram
			if(pen==2){col=(line<=buf[c]);(i<<=1)+=col;(i<<=1)+=col;												// create dft bars 
								 col=(line<=buf[c+1]);(i<<=2)+=col;(i<<=1)+=col;}}}}

void gput(int key){int line,col=0;																										// calc marquee
	for(col=0;col<5;graph(0),delay_ms(47),col++){																				// cycle cols per symbol
		for(line=0;line<39;buf[line]=buf[++line]);buf[39]=(key==32?(0):font[(key-40)*5+col]);}}	//rotate, fix space, plot new col

void scope(){i=0;
	while(++i&&(read_adc()<132));while(++i&&(read_adc()>120));													// redneck trigger
		for(read_adc(1),i=0;i<40;buf[i++]=7-((196-read_adc(6))>>4),read_adc(1))delay_us(220);graph(1);}	// fetch& scale AD to 7 pixel						// fill buffer//		for(i=0;i<40;buf[i++]/=37);

void dft(){int off,ch;signed int16 cx[32];																						// discrete fourier transformation
	for(read_adc(1),i=0;i<32;i++){buf[i]=(read_adc(6)>>4);read_adc(1);delay_us(44);cx[i]=0;}// 4 fill buffer, clear complex
	for(i=0;i<32;i++){																																	// cycle samples
		for(ch=0;ch<16;ch++){																															//       channels
			cx[ch]+=mul[buf[i]][sin[off=(i*log[ch])%64]];																		// calc imag&real with log-(co)sine entrypoints
			cx[ch|16]+=mul[buf[i]][cos[off]];}}																							// use table for multiplication
	for(i=0;i<16;i++){buf[i]=(abs(cx[i])+abs(cx[i|16]))>>6;}graph(2);}									// pseudocalc power	and plot

void main(){mode=1;setup_oscillator(0);setup_timer_1(0x85|0x30);
	setup_comparator(0xff07);setup_adc(0x50);setup_adc_ports(4);set_adc_channel(2);			// no comp, setup analog port
	set_tris_a(0b00000110);port_a_pullups(0b00000010);set_tris_c(0);d.rs=d.e=0;					// config pins, pullup for button
	delay_ms(20);for(i=1;i<=3;++i){dnib(3);delay_ms(5);}dnib(2);												// lcd warmup
	dbyt(0,32);dbyt(0,12);dbyt(0,1);dbyt(0,6);delay_ms(32);															// lcd init 32/40 single/multiline
	dbyt(0,128);dbyt(1,91);for(i=0;i<8;i++)dbyt(1,i);dbyt(1,93);												// set graph-position [and brackets]
	enable_interrupts(0x0BC0);enable_interrupts(0x020B08);															// interrupt for button
	for(i=0;i<40;buf[i++]=0);printf(gput,"SPECTRUM ANALYZER         ");									// clear buffer, splash screen
 	while(1){			
		dbyt(0,138);printf(dput,"%c%Lu   ",126,get_timer1());set_timer1(0);								// lcd use example: measure refresh
		if(mode)dft();else scope();}}