/** Version 2.00  -  76% program mem used **/

#define sleep()  __asm__ __volatile__ ("sleep") 
#define wdr()  __asm__ __volatile__ ("wdr") 
#define sei()  __asm__ __volatile__ ("sei" ::) 
#define cli()  __asm__ __volatile__ ("cli" ::)
#define nop()  __asm__ __volatile__ ("nop" ::)
#define UART_CPU               3579545      /* 3.579545Mhz */ 
#define UART_BAUD_RATE         9600         /* baud rate*/ 
#define UART_BAUD_SELECT       (UART_CPU/(UART_BAUD_RATE*16l)-1) 
#define PRINT(string) (UART_PrintfProgStr(PSTR(string)))
#define lcdata(data) lcdwrt(1, data) 
#define lcdcmd(cmd) lcdwrt(0, cmd) 

#include <avr/io.h> 
#include <avr/signal.h> 
#include <avr/pgmspace.h>

extern void UART_PrintfProgStr  (unsigned char* pBuf); 
void TXbyte( char data ); 			//Transmits 1 byte out the UART
void ewrite (char address, char data); 	//Writes char to EEPROM address
unsigned char eread (char address);	//Reads char from EEPROM address
void store(unsigned char edata);		//Compresses and appends digit to the end of eeprom
void trnsfr(char line, char eol);		//Moves digits from eeprom to LCD line
void updtlcd(unsigned char ldata);		//Handles writing new dtmf digit to LCD
void line19(void);					//restores Ln 19 before the scroll
unsigned char fltr(char fdata);		//Filters digits for 10,#,* and 0x0F
void lcdwrt(char dt, char data);		//Writes Byte to LCD dt=0 Control dt=1 data

unsigned char lcdtemp[13];				//holds bottom LCD line
unsigned char eepos;					//eeprom address of marker byte
unsigned char lcdpos;					//position of cursor on LCD
unsigned char lcdln;					//line number on LCD
unsigned char eref;						//eeprom address of last digit on Ln 18
unsigned char esrl;						//eeprom address of last digit on current lcd Ln
unsigned char redraw;					//flag to re-draw Ln 18,19 on incomming digit
unsigned char a;						//temporatry variable
unsigned char uptimeH;					//up botton release filter timer
unsigned char uptimeL;					//up botton pressed filter timer
unsigned char dntimeH;					//down botton release filter timer
unsigned char dntimeL;					//down botton pressed filter timer
volatile unsigned char up;				//up flag
volatile unsigned char dn;				//down flag
 
int main (void) 
{ 
 cli(); 
  //Setup Ports 
 DDRB = 0x00;							//Set PORTB as input
 DDRD = 0x70;							//Set PORTD output pins
 cbi(PORTB,4);							//HiZ - Disable decoder chip's output
   //Setup UATRT 
 UBRR = (char)UART_BAUD_SELECT;	 
 UCR = 0x08;	 						//enable Tx 
  //Setup TimerCounter0
 TCCR0 = 0x03;							//Set TC0 to ck/64 4.5mS IRQs
 TIMSK = 0x02;							//Enable OV0 INT
  //Setup MCU 
 GIMSK = 0x80;							//Enable INT1
 MCUCR = 0x2C;							//Setup Sleep mode & INT1 rising
 GIFR = 0xC0;							//Clear INT1 Flag
 
 for(eepos=0;eepos<255;eepos++) {			//scan eeprom for marker byte
 	if(eread(eepos)==0x0F) break;
 }							
 
 eref = eepos;							//set end of line 18 at end of eeprom
 lcdln = 19;
 redraw = 1;							//Redraw incoming screen on first digit recieved
   
 lcdcmd (0x01);						//Clear LCD, move home
 lcdcmd (0x02);						//Home Cursor
 lcdcmd (0x38);						//Set 8-bit interface
 lcdcmd (0x0C);						//No cursor, display visable
 lcdcmd (0x06);						//Incement display address
 
 TXbyte ('\r');
 TXbyte ('\n');
 PRINT ("DTMF Decoder by www.infidigm.net");	//build message on lcd and out uart
 TXbyte ('\r');
 TXbyte ('\n');
 
 for (a=0;a<255;a++) {
  	TXbyte(fltr(eread(a + eepos+1)));		//Send entire eeprom out the UART
 }
 TXbyte ('\r');
 TXbyte ('\n');
 
 sei();
 for(;;) sleep();						//idle until Interrupt
} 
 

 
SIGNAL(SIG_INTERRUPT1)				//Exturnal IRQ from DTMF decoder handler
{ 
 unsigned char digit;
 cli();
 DDRB = 0x00;							//Set PORTB = input
 sbi(PORTD,4);							//Enable decoder chip's output
 nop();
 digit = PINB;							//read dtmf digit
 cbi(PORTD,4);							//HiZ - Disable decoder chip's output
 digit=digit&0x0F;						//Stip off top 4 bits
 updtlcd(fltr(digit));					//send digit to LCD
 store(digit);							//write digit to eeprom
 TXbyte(fltr(digit));					//send digit out the UART
 sei();
} 

SIGNAL(SIG_OVERFLOW0)				//TC0 overflow IRQ handle - every 4.5mS 
{
 if((PIND >> PD0) & 1) {					//test if up button is released
 	uptimeL=22;						//reset up depressed timer
 	if(uptimeH<22)uptimeH++;				//increment up released timer
 	else up=0;						//indicate up filtered release
 }
 else {
 	uptimeH=0;				 		//reset up release timer
 	if(uptimeL>0)uptimeL--;				//increment up depressed timer
 	else {
 		if(up==0 && lcdln<19) {			//scroll up if not at end (Line 19)
 	 		redraw = 1;				//set flag to redraw incomming screen
 	 		lcdln++;					//increment line number
 			lcdcmd (0x01);				//Clear LCD, move home//clear lcd
 			trnsfr (lcdln-1, esrl-13);			//draw top line
 			lcdcmd (0xC0);						//set cursor at bottom line
 			if(lcdln!=19) trnsfr (lcdln, esrl-26);	//draw bottom line
 			esrl=esrl-13;						//adjust eeprom scroll offset
 			if(lcdln==19) {
 				line19();				//re-draw line 19
 				redraw = 0;
 			}
 			up = 1;
 		}
 	}
 }
 if((PIND >> PD2) & 1) {					//test if down button is released
 	dntimeL=22;						//reset down depressed timer
 	if(dntimeH<22)dntimeH++;				//increment down released timer
 	else dn=0;						//indicate down filtered release
 }
 else {
 	dntimeH=0;						//reset down release timer
 	if(dntimeL>0)dntimeL--;				//increment down depressed timer
 	else {							
 		if(dn==0 && lcdln>2) {			//scroll down if not at end (Line 1)
 			redraw = 1;				//set flag to redraw incomming screen
 			lcdln--;
 			lcdcmd (0x01);				//Clear LCD, move home//clear lcd
 			trnsfr (lcdln-1, esrl+13);	//draw top line
 			lcdcmd (0xC0);				//set cursor at of bottom line
 			trnsfr (lcdln, esrl);		//draw bottom line
 			esrl=esrl+13;				//adjust eeprom scroll offset
 			dn = 1;
		} 	
 	}
 }
}

void UART_PrintfProgStr(unsigned char* pBuf) 
{ 
 unsigned char pos;
 pos = 0;
 lcdcmd (0x80);						//LCD Start Position on 1st Row
 while (PRG_RDB(pBuf)!=0) { 				//Go through string until end(null)
	UDR = PRG_RDB(pBuf);				//Send string byte out UART
    	if (pos == 0x10) lcdcmd (0xC0);		//If end of 1st goto 2nd Row
	lcdata (PRG_RDB(pBuf));				//Send string byte to LCD
  	pBuf++;							//Point to next byte in string
  	pos++;							//point to next LCD position
    	while ( !(USR & (1<<UDRE)) ); 		//Wait for UART to finish TXing
 }     	
} 

void TXbyte ( char data ) 			//Transmits 1 byte out the UART
{ 
 while ( !(USR & (1<<UDRE)) );   			//wait for empty transmit buffer 
 UDR = data; 	 	   					//start transmittion 
} 


void ewrite (char address, char data)	//Writes char to EEPROM address 
{ 
 cli(); 
 while ((EECR >> EEWE) & 1); 
 EEARL = address>>1; 
 EEDR = data; 
 sbi (EECR,2); 
 sbi (EECR,1); 
 sei(); 
} 
  
unsigned char eread (char address)		//Reads char from EEPROM address 
{ 
 EEARL = address>>1; 
 sbi (EECR,0); 
 if(address&1) return (EEDR & 0x0F);		//Read LSN on odd address
 else return (EEDR >> 4);				//Read MSN on even address
} 


void store(unsigned char edata)		//Compresses and appends digit to the end of eeprom
{
 unsigned char old;
 if (eepos&1) {						//test if Marker is in MSN or LSN
 	old = eread(eepos-1);				//read byte that will be overwritten
 	old = old<<4;
 	old|= edata;						//place new in LSN
 	ewrite(eepos,old);					//write new byte
 	eepos++;							//increment eeprom address
 	old = eread(eepos+1);					//read byte that will be overwritten
 	old|= 0xF0;						//put Marker in MSN, keep data in LSN
 	ewrite(eepos,old);					//write new marker byte
 }
 else {
 	edata = (edata << 4);				//Move data in LSN to MSN
 	edata|= 0x0F;						//put Marker in LSN
 	ewrite(eepos,edata);				//write new marker and data byte
 	eepos++;
 }
}


void trnsfr(char line, char eol)		//Moves digits from eeprom to LCD line
{
 unsigned char hold,pop;
 if(line<10) {							//test if line is less than 10
 	lcdata (' ');						//write space on LCD
 	lcdata ((line|0x30));				//write 'ones' line number on LCD
 }
 else {								//if line greater than 9....
 	lcdata ('1');						//write 1 on LCD
 	lcdata (((line-10)|0x30));			//write 'ones' line number on LCD
 }
 lcdata ('-');							//write "-" after line number
 for(pop=1;pop<=13;pop++) {				//Read nibbles
 	hold = eread(pop+eref-eol-14);		//Get byte from eeprom
 	lcdata (fltr(hold));				//Send to LCD
 }
}

void updtlcd(unsigned char ldata)		//Handles writing new dtmf digit to LCD
{
 if (redraw==1 && lcdpos<13) {			// Redraw LCD if up/dn stuff is on it
 	redraw = 0;
 	esrl = 0;
 	lcdln = 19;						//reset line numbner
 	lcdcmd (0x01);						//Clear LCD, move home//clear lcd
 	trnsfr (18, 0);					//draw line 18
 	lcdcmd (0xC0);						//set cursor at begining of bottom line
 	line19();							//re-draw line 19
 }
 if (lcdpos>=13) {
 	lcdcmd (0x01);						//Clear LCD, move home//clear lcd
 	lcdata ('1');						//write "18-"
 	lcdata ('8');
 	lcdata ('-');
 	for (lcdpos=0;lcdpos<=13;lcdpos++) {	//Move bottom line to top
 		lcdata (lcdtemp[lcdpos]);
 	}
 	lcdcmd (0xC0);						//set cursor at begining of bottom line
 	lcdata ('1');						//write "19-"
 	lcdata ('9');
 	lcdata ('-');
 	lcdpos = 0;						//Reset line position
 	
 	eref = eepos;						//set end of line 18 at end of eeprom
 	esrl = 0;
 	lcdln = 19;						//reset line numbner
 }
 lcdata (ldata);						//Write digit to LCD
 lcdtemp[lcdpos] = ldata;				//Store digit in ram
 lcdpos++;
}

void line19(void)					//restores Ln 19 before the scroll
{
 lcdata ('1');							//Write "19-
 lcdata ('9');
 lcdata ('-');
 for (a=0;a<lcdpos;a++) {				//loop until all digits have been restored
 	lcdata (lcdtemp[a]);				//restore LCD Line 19 from ram
 }
}

unsigned char fltr(char fdata)		//Filters digits for 10,#, and *
{
 if(fdata==0x0F) return (0x20);			//correct for blank cell
 if(fdata==0x0A) return (0x30);			//correct for Zero from decoder
 if(fdata==0x0B) return (0x2A);			//correct for * from decoder
 if(fdata==0x0C) return (0x23);			//correct for # from decoder
 else return (fdata|0x30);
}

void lcdwrt (char dt, char data)		// Writes Byte to LCD dt=0 Control dt=1 data
{
 volatile unsigned int x;
 DDRB = 0xFF;							//Set PORTB as Output
 if (dt == 1) sbi(PORTD,5);  				//Data PD5=1 or Control PD5=0
 else cbi(PORTD,5);						
 PORTB = data;							//Send data byte (PORTB)
 for (x=0;x < 50;x++);					//Delay 250uS
  sbi(PORTD,6);	   					//Set Strobe 
 for (x=0;x < 50;x++);					//Delay 250uS
 cbi(PORTD,6);	   						//Clear Strobe 
 for (x=0;x < 200;x++);					//Delay 1000uS
 DDRB = 0x00;							//Set PORTB as Input
}