main_VU_11-14-08.c

/*
    graphic LCD backpack test code
        
        set up for the big LCD, 160x128
        
        10/16/08, everything works. Pixel, line, circle, set x, set y, print_char, clear_screen. All good.
        
        11/12/08 code jacked for VU meter
*/


#include <avr/io.h>
#include "rprintf.h"
#include <math.h>
#include <avr/interrupt.h>

#define FOSC 16000000// Clock Speed
#define BAUD 57600
#define MYUBRR FOSC/16/BAUD-1

#define WR 0        //PC0
#define RD 1        //PC1
#define CE 2        //PC2
#define CD 3        //PC3
#define HALT 4        //PC4
#define RST 5        //PC5

#define PEAK 1

#define BL_EN 2        //PB2

#define X_ENDPOINT 159
#define Y_ENDPOINT 127

//#define        CS20 0
//#define        CS21 1
//#define        CS22 2


//Define functions
//======================
void ioinit(void);      //Initializes IO
void delay_ms(uint16_t x); //General purpose delay
void delay(void);
void delay_us(uint8_t x);
void USART_Init( unsigned int ubrr);
void put_char(char byte);
void print_num(short num);
int rnd(float number);

void set_data(char data);
char read(char D_S);//reads data (D_S = 1) or status (D_S = anything else)
void write(char D_C, char byte);//writes data or command
void display_init(void);


void clear_screen(void);

void print_char(char S_R, char txt);
void del_char(char endpoint);
void pixel(char S_R, char x, char y);
void line(char S_R, char x1, char y1, char x2, char y2);
void circle(char S_R, int x, int y, int r);
void demo(void);

void erase_block(char x1, char y1, char x2, char y2);
void box(char x1, char y1, char x2, char y2);

int get_adc(void);

//======================
char x_offset = 0;
char y_offset = 127;

unsigned char RX_array[256];
volatile unsigned short RX_in = 0;
unsigned short RX_read = 0;

static char logo[30] = {0x01,0xC0,0x03,0x80,0x03,0x80,0x01,0xD0,
                                                0x01,0xF8,0x0C,0xF8,0x18,0xF8,0x1F,0xF8,
                                                0x1F,0xF8,0x1F,0xF0,0x1F,0xE0,0x1F,0xC0,
                                                0x1C,0x00,0x18,0x00,0x10,0x00};

//Jacked from Sinister 7 code
static char text_array[130] = {0x00,0x00,0x00,0x00,0x00,/*space*/
                              0x00,0xF6,0xF6,0x00,0x00,/*!*/
                              0x00,0xE0,0x00,0xE0,0x00,/*"*/
                              0x28,0xFE,0x28,0xFE,0x28,/*#*/
                              0x00,0x64,0xD6,0x54,0x08,/*$*/
                              0xC2,0xCC,0x10,0x26,0xC6,/*%*/
                              0x4C,0xB2,0x92,0x6C,0x0A,/*&*/
                              0x00,0x00,0xE0,0x00,0x00,/*'*/
                              0x00,0x38,0x44,0x82,0x00,/*(*/
                              0x00,0x82,0x44,0x38,0x00,/*)*/
                              0x88,0x50,0xF8,0x50,0x88,/***/
                              0x08,0x08,0x3E,0x08,0x08,/*+*/
                              0x00,0x00,0x05,0x06,0x00,/*,*/
                              0x08,0x08,0x08,0x08,0x08,/*-*/
                              0x00,0x00,0x06,0x06,0x00,/*.*/
                              0x02,0x0C,0x10,0x60,0x80,/*/*/
                              0x7C,0x8A,0x92,0xA2,0x7C,/*0*/
                              0x00,0x42,0xFE,0x02,0x00,/*1*/
                              0x42,0x86,0x8A,0x92,0x62,/*2*/
                              0x44,0x82,0x92,0x92,0x6C,/*3*/
                              0x10,0x30,0x50,0xFE,0x10,/*4*/
                              0xE4,0xA2,0xA2,0xA2,0x9C,/*5*/
                              0x3C,0x52,0x92,0x92,0x0C,/*6*/
                              0x80,0x86,0x98,0xE0,0x80,/*7*/
                              0x6C,0x92,0x92,0x92,0x6C,/*8*/
                              0x60,0x92,0x92,0x94,0x78};/*9*/
                                                          
                                                          
static char line_array[284] = {10,80,40,37,
                                                                12,81,41,38,
                                                                14,82,42,38,
                                                                16,83,43,39,
                                                                18,84,45,40,
                                                                20,85,46,40,
                                                                22,86,47,41,
                                                                24,87,48,41,
                                                                26,88,49,42,
                                                                28,89,50,42,
                                                                30,90,51,42,
                                                                32,91,53,43,
                                                                34,92,54,44,
                                                                36,92,55,44,
                                                                38,93,56,44,
                                                                40,94,57,45,
                                                                42,94,58,45,
                                                                44,95,59,45,
                                                                46,95,61,46,
                                                                48,96,62,46,
                                                                50,96,63,46,
                                                                52,97,64,46,
                                                                54,97,65,47,
                                                                56,98,66,47,
                                                                58,98,67,47,
                                                                60,98,69,47,
                                                                62,99,70,47,
                                                                64,99,71,47,
                                                                66,99,72,48,
                                                                68,99,73,48,
                                                                70,100,74,48,
                                                                72,100,75,48,
                                                                74,100,77,48,
                                                                76,100,78,48,
                                                                78,100,79,48,
                                                                80,100,80,48,
                                                                82,100,81,48,
                                                                84,100,82,48,
                                                                86,100,83,48,
                                                                88,100,85,48,
                                                                90,100,86,48,
                                                                92,99,87,48,
                                                                94,99,88,48,
                                                                96,99,89,47,
                                                                98,99,90,47,
                                                                100,98,91,47,
                                                                102,98,93,47,
                                                                104,98,94,47,
                                                                106,97,95,47,
                                                                108,97,96,46,
                                                                110,96,97,46,
                                                                112,96,98,46,
                                                                114,95,99,46,
                                                                116,95,101,45,
                                                                118,94,102,45,
                                                                120,94,103,45,
                                                                122,93,104,44,
                                                                124,92,105,44,
                                                                126,92,106,44,
                                                                128,91,107,43,
                                                                130,90,109,42,
                                                                132,89,110,42,
                                                                134,88,111,42,
                                                                136,87,112,41,
                                                                138,86,113,41,
                                                                140,85,114,40,
                                                                142,84,115,40,
                                                                144,83,117,39,
                                                                146,82,118,38,
                                                                148,81,119,38,
                                                                150,80,120,37};









ISR (SIG_UART_RECV)                                                                        //USART Receive Interrupt
{
        cli();//Disable Interrupts
        RX_array[RX_in] = UDR0;
        
        RX_in++;
        
        if (RX_in >= 256) RX_in = 0;
        
        sei();//Enable Interrupts
        
}


int main (void)
{
        char x, y, a, temp;
        //short a, b;
        float temp_y, temp_y2, temp_x;
        int q;
        
        //char a = 0;
    ioinit(); //Setup IO pins and defaults
        //USART_Init( MYUBRR);
        //rprintf_devopen(put_char); /* init rrprintf */
        
        //reset the display
        delay_ms(1);
        PORTC |= (1<<RST);
        
        //initialize the display
        display_init();

        clear_screen();
        
        //Backlight on
        PORTB &= (~(1<<BL_EN));
        
        //circle(1,80,-20,142);
        //circle(1,80,-20,70);
        
        for (x = 0; x < 160; x++)
        {
                //temp_y = ((sqrt((r^2) - ((x - 80)*(x - 80)))) - 20)
                temp_y = ((sqrt((23716) - ((x - 80)*(x - 80)))) - 30);
                temp_y2 = ((sqrt((23409) - ((x - 80)*(x - 80)))) - 30);
                
                //temp_y *= (-1);
                pixel(1, x, (char)(temp_y));
                pixel(1, x, (char)(temp_y2));
        }
        
        for (x = 0; x < 160; x++)
        {
                //temp_y = ((sqrt((r^2) - ((x - 80)*(x - 80)))) - 20)
                temp_y = ((sqrt((20164) - ((x - 80)*(x - 80)))) - 30);
                temp_y2 = ((sqrt((19881) - ((x - 80)*(x - 80)))) - 30);
                
                //temp_y *= (-1);
                pixel(1, x, (char)(temp_y));
                pixel(1, x, (char)(temp_y2));
        }
        
        for (x = 40; x < 120; x++)
        {
                temp_y = ((sqrt((4900) - ((x - 80)*(x - 80)))) - 30);
                temp_y2 = ((sqrt((4761) - ((x - 80)*(x - 80)))) - 30);
                
                //temp_y *= (-1);
                pixel(1, x, (char)(temp_y));
                pixel(1, x, (char)(temp_y2));
        }
        
        //=======================================================================
        /*
        for (x = 109; x < 158; x++)
        {
                temp_y = ((sqrt((19600) - ((x - 80)*(x - 80)))) - 30);
                temp_y2 = ((sqrt((19321) - ((x - 80)*(x - 80)))) - 30);
                
                //temp_y *= (-1);
                pixel(1, x, (char)(temp_y));
                pixel(1, x, (char)(temp_y2));
        }
        */
        
        for (x = 108; x < 156; x++)
        {
                //temp_y = ((sqrt((19044) - ((x - 80)*(x - 80)))) - 30);
                temp_y2 = ((sqrt((18225) - ((x - 80)*(x - 80)))) - 30);
                
                //temp_y *= (-1);
                //pixel(1, x, (char)(temp_y));
                pixel(1, x, (char)(temp_y2));
        }
        
        line(1,0,87,40,27);
        line(1,1,87,41,27);
        line(1,120,27,159,87);
        line(1,119,27,158,87);
        
        //cleanup================================================================
        pixel(1,80,122);
        pixel(0,80,124);
        
        pixel(1,80,110);
        pixel(0,80,112);
        
        pixel(1,80,38);
        pixel(0,80,40);
        
        //numbers================================================================
        x_offset = 1, y_offset = 99;
        print_char(1,'2');
        y_offset = 101;
        print_char(1,'0');
        
        line(1, 9, 92, 12, 86);
        line(1, 8, 92, 11, 86);
        
        x_offset = 24, y_offset = 111;
        print_char(1,'1');
        y_offset = 112;
        print_char(1,'0');
        
        line(1,30, 101, 32, 95);
        line(1, 31, 101, 33, 95);
        
        x_offset = 48, y_offset = 117;
        print_char(1,'7');
        
        line(1,50, 108, 51, 101);
        line(1, 51, 108, 52, 101);

        x_offset = 66, y_offset = 119;
        print_char(1,'5');
        
        line(1,68, 109, 69, 103);
        line(1, 69, 109, 70, 103);
        
        x_offset = 84, y_offset = 119;
        print_char(1,'3');
        
        line(1,86, 109, 86, 103);
        line(1, 87, 109, 87, 103);
        
        x_offset = 110, y_offset = 116;
        print_char(1,'0');
        
        line(1,108, 102, 109, 106);
        line(1,109, 102, 110, 106);
        
        x_offset = 135, y_offset = 108;
        print_char(1,'3');
        
        line(1,132, 93, 135, 100);
        line(1,133, 93, 136, 100);
        
        //logo==================================================================
        y = 28;
                
        q = 0;
        while(q < 30)
        {
                temp = logo[q];
                for (x = 72; x < 80; x++)
                {
                        if (temp & 0x80) pixel(1,x,y);
                        
                        temp <<= 1;
                }
                q++;
                temp = logo[q];
                for (x = 80; x < 88; x++)
                {
                        if (temp & 0x80) pixel(1,x,y);
                        
                        temp <<= 1;
                }
                y--;
                q++;
        }        
        
        x = 0;
        line(1, line_array[x*4], line_array[x*4+1], line_array[x*4+2], line_array[x*4+3]);
        
        while(1)
        {
                q = get_adc();
                
                y = (char)(rnd(q / 13.5)-10);
                
                delay_ms(25);
                
                if (y != x)
                {
                        line(0, line_array[x*4], line_array[x*4+1], line_array[x*4+2], line_array[x*4+3]);
                        line(1, line_array[y*4], line_array[y*4+1], line_array[y*4+2], line_array[y*4+3]);
                        x = y;
                        
                        if (y >= 50) PORTD |= (1<<PEAK);
                        else PORTD &= (~(1<<PEAK));
                }
        
                
                
                
                
                //rprintf("%d\r\n",q);
                

                /*
                for (x = 10; x <= 80; x += 4)
                {
                        
                        
                        //draw new line
                        line(1, line_array[(x-10)*4], line_array[(x-10)*4+1], line_array[(x-10)*4+2], line_array[(x-10)*4+3]);
                        line(1, line_array[(x-10)*4]+1, line_array[(x-10)*4+1], line_array[(x-10)*4+2]+1, line_array[(x-10)*4+3]);
                        delay_ms(3);
                        line(0, line_array[(x-10)*4], line_array[(x-10)*4+1], line_array[(x-10)*4+2], line_array[(x-10)*4+3]);
                        line(0, line_array[(x-10)*4]+1, line_array[(x-10)*4+1], line_array[(x-10)*4+2]+1, line_array[(x-10)*4+3]);
                        
                }
                

                
                for (x = 80; x >= 10; x -= 4)
                {
                        
                        //draw new line
                        line(1, line_array[(x-10)*4], line_array[(x-10)*4+1], line_array[(x-10)*4+2], line_array[(x-10)*4+3]);
                        line(1, line_array[(x-10)*4]+1, line_array[(x-10)*4+1], line_array[(x-10)*4+2]+1, line_array[(x-10)*4+3]);
                        delay_ms(3);
                        line(0, line_array[(x-10)*4], line_array[(x-10)*4+1], line_array[(x-10)*4+2], line_array[(x-10)*4+3]);
                        line(0, line_array[(x-10)*4]+1, line_array[(x-10)*4+1], line_array[(x-10)*4+2]+1, line_array[(x-10)*4+3]);
                }
                */
                
        }
        
        while(1);
        //{
                
                
                
                
                
                
                /*
                if(RX_in != RX_read)
                {
                        x = RX_array[RX_read];
                        RX_read++;
                        if(RX_read >= 256) RX_read = 0;
                        
                        //Backspace===================================================
                        if(x == 8) del_char(0);
                        
                        //Special commands
                        else if (x == 124)
                        {        
                                //make sure the next byte is there
                                while(RX_in == RX_read);
                                
                                //0, clear screen======================================================
                                if(RX_array[RX_read] == 0)
                                {
                                        clear_screen();
                                        RX_read++;
                                        if(RX_read >= 256) RX_read = 0;
                                }
                                
                                
                                //Backlight on/off
                                else if(RX_array[RX_read] == 2)
                                {
                                        y = PINB;
                                        if (y & (1<<BL_EN)) PORTB &= (~(1<<BL_EN));
                                        else PORTB |= (1<<BL_EN);
                                        RX_read++;
                                }
                                
                                //demo mode
                                else if(RX_array[RX_read] == 4)
                                {
                                        RX_in = 0, RX_read = 0;
                                        demo();
                                        clear_screen();
                                        RX_in = 0;
                                }
                                
                                else
                                {                                
                                        //set x or y=========================================================
                                        if((RX_array[RX_read] == 24) | (RX_array[RX_read] == 25))
                                        {
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                                while(RX_in == RX_read);//wait for byte
                                                if (RX_array[RX_read-1] == 24) x_offset = RX_array[RX_read];
                                                else if (RX_array[RX_read-1] == 25) y_offset = RX_array[RX_read];
                                                
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                                
                                                if (x_offset > 159) x_offset = 159;
                                                if (y_offset > 127) y_offset = 127;

                                        }

                                        //set pixel=========================================================
                                        if (RX_array[RX_read] == 16)
                                        {
                                                //need 3 bytes
                                                for (y = 0; y < 3; y++)
                                                {
                                                        RX_read++;
                                                        if(RX_read >= 256) RX_read = 0;
                                                        while(RX_in == RX_read);//wait for byte
                                                }
                                                
                                                pixel(RX_array[RX_read], RX_array[RX_read-2], RX_array[RX_read-1]);
                                                
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;

                                        }

                                        //<ctrl>c, circle======================================================
                                        if(RX_array[RX_read] == 3)
                                        {
                                                //need 4 bytes
                                                for (y = 0; y < 4; y++)
                                                {
                                                        RX_read++;
                                                        if(RX_read >= 256) RX_read = 0;
                                                        while(RX_in == RX_read);//wait for byte
                                                }
                                                
                                                circle(RX_array[RX_read], RX_array[RX_read-3], RX_array[RX_read-2], RX_array[RX_read-1]);
                                                
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                        }
                                        
                                        
                                        //<ctrl>e, erase block======================================================
                                        if(RX_array[RX_read] == 5)
                                        {
                                                //need 4 bytes
                                                for (y = 0; y < 4; y++)
                                                {
                                                        RX_read++;
                                                        if(RX_read >= 256) RX_read = 0;
                                                        while(RX_in == RX_read);//wait for byte
                                                }
                                                
                                                erase_block(RX_array[RX_read-3], RX_array[RX_read-2], RX_array[RX_read-1], RX_array[RX_read]);
                                                
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                        }
                                        
                                        
                                        //<ctrl>o, box, running out of meaningful letters======================================================
                                        if(RX_array[RX_read] == 15)
                                        {
                                                //need 4 bytes
                                                for (y = 0; y < 4; y++)
                                                {
                                                        RX_read++;
                                                        if(RX_read >= 256) RX_read = 0;
                                                        while(RX_in == RX_read);//wait for byte
                                                }
                                                
                                                box(RX_array[RX_read-3], RX_array[RX_read-2], RX_array[RX_read-1], RX_array[RX_read]);
                                                
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                        }


                                        //<ctrl>L, line========================================================
                                        else if (RX_array[RX_read] == 12)
                                        {
                                                //need 5 bytes
                                                for (y = 0; y < 5; y++)
                                                {
                                                        RX_read++;
                                                        if(RX_read >= 256) RX_read = 0;
                                                        while(RX_in == RX_read);//wait for byte
                                                }
                                                
                                                line(RX_array[RX_read], RX_array[RX_read-4], RX_array[RX_read-3], RX_array[RX_read-2], RX_array[RX_read+-1]);
                                                RX_read++;
                                                if(RX_read >= 256) RX_read = 0;
                                        }
                                        
                                        
                                }
        
                        }
                        
                        //print character to the screen===============================================
                        else
                        {
                                del_char(1);
                                print_char(1, x);
                        }
                }
                */
                
        //}
        
        

}

void ioinit (void)
{
        
    //1 = output, 0 = input
        
        /*
        WR        //PC0
        RD        //PC1
        CE        //PC2
        C_D //PC3
        HALT        //PC4
        RST        //PC5
        */

        PORTB |= (1<<BL_EN);//Backlight off
        DDRB |= (1<<BL_EN);//set PB2 as output
        
        //set these in the read/write functions instead of here
        //DDRB = 0b00000011; //PB0 and PB1 are outs
        //DDRD = 0b11111100; //PD2-PD7 are also outs.  Ports B and D are the data bus.

        PORTC = ((1<<WR) | (1<<RD) | (1<<CE) | (1<<CD) | (1<<HALT));
        PORTC &= (~(1<<RST));//set the reset line low at power up
        DDRC = ((1<<WR) | (1<<RD) | (1<<CE) | (1<<CD) | (1<<HALT) | (1<<RST));
        
        DDRD = (1<<PEAK);
        PORTD &= (~(1<<PEAK));
        
        //Init timer 2
    //8,000,000 / 8 = 1,000,000
    TCCR2B = (1<<CS21); //Set Prescaler to 8. CS21=1
        //TCCR2 = ((1<<CS20) | (1<<CS22) | (1<<CS22));
        
}

//General short delays
void delay_ms(uint16_t x)
{
        for (; x > 0 ; x--)
    {
        delay_us(250);
        delay_us(250);
        delay_us(250);
        delay_us(250);
    }
        
}

//General short delays
void delay_us(uint8_t x)
{
        char temp;
        
        if (x == 0) temp = 1;
        else temp = x;
    //TIFR = 0x01; //Clear any interrupt flags on Timer2
        TIFR2 |= 0x01;
    
    TCNT2 = 256 - temp; //256 - 125 = 131 : Preload timer 2 for x clicks. Should be 1us per click

    //while( (TIFR & (1<<TOV2)) == 0);
        while(!(TIFR2 & 0x01));
        
        if (x == 0) return;//this is for display timing
        
        
        //The prescaler doesn't allow for a setting of 16, just 8 or 32. So, we do this twice.
        TIFR2 |= 0x01;
    
    TCNT2 = 256 - temp; //256 - 125 = 131 : Preload timer 2 for x clicks. Should be 1us per click

    //while( (TIFR & (1<<TOV2)) == 0);
        while(!(TIFR2 & 0x01));
        
}


void USART_Init( unsigned int ubrr)
{
        // Set baud rate 
        UBRR0H = (unsigned char)(ubrr>>8);
        UBRR0L = (unsigned char)ubrr;
        // Enable receiver and transmitter 
        //UCSRB = (1<<RXEN)|(1<<TXEN);
        UCSR0B = (1<<RXCIE0)|(1<<RXEN0)|(1<<TXEN0);        //Enable Interrupts on receive character
        // Set frame format: 8data, 2stop bit 
        //UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
        UCSR0C = (1<<UMSEL00)|(1<<UCSZ00)|(1<<UCSZ01);
        sei();
}



void put_char(char byte)
{
        /* Wait for empty transmit buffer */
        while ( !( UCSR0A & (1<<UDRE0)) );
        /* Put data into buffer, sends the data */
        UDR0 = byte;
}

//delay for display timing
void delay(void)
{
        char y;
        
        for(y = 0; y < 20; y++)
        {
                asm volatile ("nop");
                
        }
        
        /*
        asm volatile ("nop");
        asm volatile ("nop");
        asm volatile ("nop");
        asm volatile ("nop");
        asm volatile ("nop");
        */
        
}

//set data port
void set_data(char data)
{
        //PORTB
        //DB0 = PB0
        //DB1 = PB1
        
        PORTB &= 0xFC;
        
        //PORTD
        //DB2 = PD2
        //DB3 = PD3
        //DB4 = PD4
        //DB5 = PD5
        //DB6 = PD6
        //DB7 = PD7
        
        PORTD &= 0x03;
        
        PORTB |= (data & 0x03);
        PORTD |= (data & 0xFC);

}


//Reads data or status
//for data D_S = 1, for status D_S = 0
//returns the value of the data bus
char read(char D_S)
{
        char data1 = 0, data2 = 0;
        
        DDRB &= 0xFC;//PB0 and PB1 inputs
        DDRD &= 0x02;//everything but PD1 as input
        
        PORTC &= ~((1 << RD) | (1 << CE));//CD high for status
        if (D_S == 1) PORTC &= ~(1 << CD);//CD down for data
        
        delay_us(0);
        
        data1 = PINB;
        data1 &= 0x03;
        
        data2 = PIND;
        data2 &= 0xFC;
        
        data1 |= data2;
        
        PORTC |= ((1 << CD) | (1 << RD) | (1 << CE));//all up
        
        delay_us(0);
        
        return data1;

}


//Writes data (D_C = 1) or command (D_C = anything else)
void write(char D_C, char byte)
{
        DDRB |= 0x03; //PB0 and PB1 are outs
        DDRD |= 0xFC; //PD2-PD7 are also outs.  Ports B and D are the data bus
        
        set_data(byte);
        
        if (D_C == 1) PORTC &= ~((1 << WR) | (1 << CE) | (1 << CD));//down
        else PORTC &= ~((1 << WR) | (1 << CE));//down
        
        delay_us(0);
        PORTC |= ((1 << CD) | (1 << WR) | (1 << CE));//all up
        delay();
        DDRB &= 0xFC;//PB0 and PB1 inputs
        DDRD &= 0x02;//everything but PD1 as input
        
        delay_us(0);

}



void display_init(void)
{
        //set graphics home address to 0
        while(!(read(0) & 3));//read status
        write(1, 0);
        while(!(read(0) & 3));//read status
        write(1, 0);
        while(!(read(0) & 3));//read status
        write(0, 0x42);

        //set graphics area
        while(!(read(0) & 3));//read status
        write(1, 20);//20 bytes, 160/8
        while(!(read(0) & 3));//read status
        write(1, 0);
        while(!(read(0) & 3));//read status
        write(0, 0x43);
        
        //set mode
        while(!(read(0) & 3));//read status
        write(0, 0x80);//Or, with internal character generator
        
        //set display mode
        while(!(read(0) & 3));//read status
        write(0, 0x98);//Graphics on

}





void clear_screen(void)
{
        int x;
        
        //set address pointer to 0, start of graphics
        while(!(read(0) & 3));//read status
        write(1, 0);
        while(!(read(0) & 3));//read status
        write(1, 0);
        while(!(read(0) & 3));//read status
        write(0, 0x24);
        
        for(x = 0; x < 0xA00; x++)
        {
                while(!(read(0) & 3));//read status
                write(1, 0);
                while(!(read(0) & 3));//read status
                write(0, 0xC0);
        }
        
        x_offset = 0;
        y_offset = 127;
}

/*
void set_cursor(char x_spot, char y_spot)
{
        //set address pointer to 0, start of graphics
        while(!(read(0) & 3));//read status
        write(1, x_spot);
        while(!(read(0) & 3));//read status
        write(1, y_spot);
        while(!(read(0) & 3));//read status
        write(0, 0x21);

}
*/

void pixel(char S_R, char x, char y)
{
        short address = 0;
        char byte = 0;
                
        //don't try to print something outside of our range
        if ((x > 159) | (y > 127)) return;
        
        address = ((127-y) * 20) + (x / 8);
        
        //set address pointer
        while(!(read(0) & 3));//read status
        byte = (char)(address & 0xFF);

        write(1, byte);//20 bytes, 160/8
        
        while(!(read(0) & 3));//read status
        byte = (char)((address & 0xFF00) >> 8);

        write(1, byte);
        
        while(!(read(0) & 3));//read status
        write(0, 0x24);
        
        byte = ~(x % 8);

        byte |= 0xF8;
        if (S_R == 0) byte &= 0xF7;
        
        //set-reset bit
        while(!(read(0) & 3));//read status
        write(0, byte);
        
}



void line(char S_R, char x1, char y1, char x2, char y2)
{
        float m, q;
        int x_dif, y_dif;
        int a, b, c;
        
        //if ((x1 > X_ENDPOINT) | (x2 > X_ENDPOINT)) return;
        //if ((x1 < 0) | (x2 < 0)) return;
        //if ((y1 > Y_ENDPOINT) | (y2 > Y_ENDPOINT)) return;
        //if ((y1 < 0) | (y2 < 0)) return;
        
        x_dif = x2 - x1;
        y_dif = y2 - y1;
        if (y_dif < 0) y_dif *= (-1);
        

        m = (float)(y2 - y1) / (float)(x2 - x1);
        
        b = y1-(m*x1);
        
        if(x_dif >= y_dif)
        {
                for (a = x1; a <= x2; a++)
                {
                        pixel(S_R, (char)a, (char)((m*a)+b));
                        //delay_ms(25);
                }
        }
        
        else
        {
                if (y2 > y1)
                {
                        for (a = y1; a <= y2; a++)
                        {
                                if (x_dif == 0) c = x1;
                                else
                                {
                                        q = (((float)(a-b))/m);
                                        c = rnd(q);
                                }
                                
                                pixel(S_R, (char)c, (char)a);
                                //delay_ms(25);
                        }
                }
                
                else if (y1 > y2)
                {
                        for (a = y1; a >= y2; a--)
                        {
                                if (x_dif == 0) c = x1;
                                else 
                                {
                                        q = (((float)(a-b))/m);
                                        c = rnd(q);
                                }
                        
                                pixel(S_R, (char)c, (char)a);
                                //delay_ms(25);
                        }
                }
        }
                
}



void circle(char S_R, int x, int y, int r)
{
        int x1 = 0, x2 = 0;
        int x_line = 0, y_line = 0;
        int temp_y;
        int temp_x;
        //float x_float, y_float, r_float;
        
        x1 = x - r;
        x2 = x + r;
        
        for (temp_x = x1; temp_x <= x2; temp_x++)
        {
                temp_y = ((sqrt((r*r) - ((temp_x - x)*(temp_x - x)))) - y);
                
                temp_y *= (-1);
                
                /*
                print_num((short)temp_x);
                put_char(9);
                print_num((short)temp_y);
                put_char(10);
                put_char(13);
                */
                if (temp_x > x1)
                {
                        //line(S_R, (char)x_line, (char)y_line, (char)temp_x, (char)temp_y);
                        line(S_R, (char)x_line, (char)(2*y - y_line), (char)temp_x, (char)(2*y - temp_y));
                }
                        
                else 
                {
                        //pixel(S_R, (char)temp_x, (char)temp_y);
                        pixel(S_R, (char)temp_x, (char)(y + y - temp_y));
                }
                
                x_line = temp_x;
                y_line = temp_y;
                
                //
                
                
        }
        

}


int rnd(float number)
{
        int a;
        float b;
        
        a = number / 1;
        b = number - a;
        
        if (b >= 0.5) a++;
        
        return a;

}


void print_char(char S_R, char txt)
{
    short text_array_offset = (txt - 32)*5, j;
    char x, k;
        
        
    for (j = text_array_offset; j < text_array_offset+5; j++)
    {
                
                
                k = text_array[j];
                
                for (x = 0; x < 8; x++)
                {
                        if(k & 0x80) pixel(S_R, x_offset, y_offset - x);
                        k <<= 1;
                }
                        
                //if (j == text_array_offset+5) x_offset++;//blank byte for letter spacing

                        
                x_offset++;
                
    }
        
        x_offset++;
        
    if ((x_offset + 6) > 159)
        {
                x_offset = 0;
                if (y_offset <= 7) y_offset = 127;
                else y_offset -= 8;
                
        }
        
}



void print_num(short num)
{
        short a;
        char b, c;
        a = num;
        
        //print hex
        for (c = 0; c < 4; c++)
        {
                b = (char)((a & 0xF000) >> 12);
                if (b < 10) put_char(b+48);
                else put_char(b+55);
                a <<= 4;
        }
        
        //decimal
        /*
        b = a/100;
        putchr(b+48);
        a -= b*100;
        b = a/10;
        putchr(b+48);
        a -= b*10;
        putchr(a+48);
        */
        
}


void demo(void)
{
        char x, y, temp;
        int q = 0;
        
        while(1)
        {        
                x_offset = 0;
                y_offset = 127;
        
                for (y = 0; y < 5; y++)
                {
                        for (x = 32; x < 123; x++)
                        {        
                                del_char(1);
                                print_char(1, x);
                                if (RX_in > 0) return;
                        }
                }
                
                clear_screen();
                
                for (y = 0; y < 5; y++)
                {
                        for (x = 32; x < 123; x++)
                        {
                                //x_offset += 4;
                                y_offset -= 6;
                                if (y_offset <= 8) y_offset = 127;
                                del_char(1);
                                print_char(1, x);
                                if (RX_in > 0) return;
                        }
                }
                
                clear_screen();
                
                //draw circles================================
                for (x = 5; x < 120; x += 5)
                {
                        circle(1,80,64,x);
                        if (RX_in > 0) return;
                }
                
                
                //draw lines===================================
                y = Y_ENDPOINT;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(1,0,y,x,0);
                        y -= 16;
                }
                
                y = 0;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(1,x,0,X_ENDPOINT,y);
                        y += 16;
                }
                
                y = Y_ENDPOINT;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(1,x,Y_ENDPOINT,X_ENDPOINT,y);
                        y -= 16;
                }
                
                y = 0;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(1,0,y,x,Y_ENDPOINT);
                        y += 16;
                }
                
                
                //erase circles================================
                for (x = 5; x < 120; x += 5)
                {
                        circle(0,80,64,x);
                        if (RX_in > 0) return;
                }

                //erase lines===================================
                y = Y_ENDPOINT;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(0,0,y,x,0);
                        y -= 16;
                }
                
                y = 0;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(0,x,0,X_ENDPOINT,y);
                        y += 16;
                }
                
                y = Y_ENDPOINT;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(0,x,Y_ENDPOINT,X_ENDPOINT,y);
                        y -= 16;
                }
                
                y = 0;
                
                for (x = 0; x < X_ENDPOINT; x += 20)
                {
                        line(0,0,y,x,Y_ENDPOINT);
                        y += 16;
                }
                
                if (RX_in > 0) return;
                
                //Boxes=================================================================
                y = 111;
                for (x = 0; x <= 140; x += 10)
                {
                        erase_block(x, y, x+16, y+16);
                        box(x, y, x+16, y+16);
                        y -= 7;
                }
                
                
                //x = 110;
                y = 28;
                //Logo=================================================================
                q = 0;
                while(q < 30)
                {
                        temp = logo[q];
                        for (x = 140; x < 148; x++)
                        {
                                if (temp & 0x80) pixel(1,x,y);
                                
                                temp <<= 1;
                        }
                        q++;
                        temp = logo[q];
                        for (x = 148; x < 156; x++)
                        {
                                if (temp & 0x80) pixel(1,x,y);
                                
                                temp <<= 1;
                        }
                        y--;
                        q++;
                }        
                
                delay_ms(3000);
                clear_screen();
                
        }
        

}

//Deletes a character. Endpoint == 0 for a backwards delete,
//Endpoint != 0 to erase spot for a new character write
void del_char(char endpoint)
{
        char a, y;
        
        if (endpoint == 0)//Backwards delete
        {
                if (x_offset <= 5)
                {
                        //x_offset = 150;
                        //if (y_offset >= 120) y_offset = 7;
                        //else y_offset += 8;
                        
                        x_offset += 152;
                        y_offset += 8;
                        
                        if (y_offset > 127) y_offset -= 128;
                }
                
                else x_offset -= 6;
        }
        /*        
        for (a = 0; a < 6; a++)
        {                                        
                for (y = 0; y < 8; y++)
                {
                        pixel(0, x_offset + a, y_offset - y);
                        
                }
        }
        */
        
        for (a = x_offset; a < x_offset + 6; a++)
        {                                        
                for (y = y_offset - 7; y <= y_offset; y++)
                {
                        pixel(0, a, y);
                        //put_char('L');
                }
        }
                
}


void erase_block(char x1, char y1, char x2, char y2)
{
        static char temp_x = 0, temp_y = 0;
        
        for (temp_y = y2; temp_y >= y1; temp_y--)
        {
                for (temp_x = x1; temp_x <= x2; temp_x++)
                {
                        pixel(0, temp_x, temp_y);
                        
                        //rprintf("%d ",temp_x);
                        //rprintf("%d \r\n",temp_y);
                        //delay_ms(1000);
                        
                }
        }        
        
        

}

void box(char x1, char y1, char x2, char y2)
{
        //static char temp_x = 0, temp_y = 0;
        
        line(1, x1, y1, x1, y2);
        line(1, x1, y1, x2, y1);
        line(1, x2, y1, x2, y2);
        line(1, x1, y2, x2, y2);

}


int get_adc(void)
{
        //ADC result vars
        int l;//x low register
        //int h;//x high register
        int l2;//temp low
        int h2;//temp high
        
        //int Vref = 502;//reference V in mV

        //adc conversion
        ADMUX = ((1 << MUX1)|(1 << MUX2) | (0x40));//ADC6, AVcc as Vref
        ADCSRA = (1 << ADEN)|(1 << ADSC)|(1<<ADPS2)|(1<<ADPS1);
        
        while(ADCSRA & (1 << ADSC));
        l2 = (ADCL & 0xFF);
        h2 = (ADCH & 0x03);
        //rprintf("%d %d\r\n", h2, l2);
        
        //h2 = h2 << 8;
        //h2 = ((h2 + l2)*Vref)/1024;
        h2 <<= 8;
        h2 |= l2;
        //l = (ADCH & 0x03) << 8;
        //l |= ADCL;
        
        return (int)h2;
        //return 512;
        
        //l = ADCL;
        //h = ADCH & 0x03;
        //h = h << 8;
        //h = ((h + l)*Vref)/512;


}