#include <90s8515.h>
#include <stdio.h>
#include <delay.h>     
#include "send.c"

// the number of bytes of data the camera returns                      
#define PIC_SIZE		20680

// the baud rate should be 57,600
#define BAUD_RATE		7
#define UCR_SETTING		0x18

#define SNAPSHOT_BUTTON		PIND.2 
#define SNAPSHOT_LED		PORTD.4

#define CAPTURE_BUTTON		PIND.3
#define CAPTURE_LED		PORTD.5

// defines for the state of continuous capture mode
#define OFF			0
#define ON			1
#define SWITCH_ON		2
#define SWITCH_OFF		3

unsigned char capture = OFF;  
unsigned char picture[PIC_SIZE];
unsigned char count=0;

void programLoop();

// check if the capture button has been pressed every 30 ms
// and set the capture variable accordingly

interrupt [TIM1_COMPA] void cmpA(void){
	if(CAPTURE_BUTTON == 0){
		if(capture == ON) capture = SWITCH_OFF;
		else if(capture == OFF) capture = SWITCH_ON;
	} else {
		if(capture == SWITCH_ON){
			capture = ON;
			CAPTURE_LED = 0;
		} else if(capture == SWITCH_OFF){
			capture = OFF;
			CAPTURE_LED = 1;
		}
	}

	count++;
}                                           

// if an error is encountered, blink some LED's
void error(){ 
	SNAPSHOT_LED = 1;
	CAPTURE_LED = 0;

	while(1){
		SNAPSHOT_LED = !SNAPSHOT_LED;
		CAPTURE_LED = !CAPTURE_LED;
		delay_ms(1000);
	} 
}
              
// sends a one character command to the camera
void send_command(unsigned char cmd){
	putchar(0x02);		// STX
	putchar(cmd);		// command
	putchar(0x00);		// 0x00
	putchar(0x03);		// ETX
}

unsigned char getchar_timeout(){
	#asm
	cli
	#endasm
	count=0;
	#asm
	sei
	#endasm
	while(!USR.7){
		if(count >= 200){
			CAPTURE_LED=1;
			SNAPSHOT_LED=1;
			programLoop();
			return 0;
		}
	}
	return getchar();
}

// gets an expected response from the camera
void get_response(unsigned char rsp){
	if(getchar_timeout() != 0x06) error();		// ACK
	if(getchar_timeout() != 0x02) error();		// STX
	if(getchar_timeout() != rsp) error();		// response
	if(getchar_timeout() != 0x00) error();		// 0x00
	if(getchar_timeout() != 0x03) error();		// ETX
}
 
// gets the image data from the camera and buffers
// it into memory
unsigned char get_picture(){
	unsigned int i;
	
	if(getchar_timeout() != 0x06) error();		// ACK
	if(getchar_timeout() != 0x02) error();		// STX
	if(getchar_timeout() != 'u') error();		// response
	if(getchar_timeout() != 164) error();		// N1 = 164
	if(getchar_timeout() != 2) error();		// N2 = 2
	if(getchar_timeout() != 124) error();		// N3 = 124
	if(getchar_timeout() != 16) error();		// N4 = 16
	
	for(i = 0; i < PIC_SIZE; i++){
		picture[i] = getchar_timeout();
	}    
	
	if(getchar_timeout() != 0x03) error();		// ETX 
	return 1;
}


// sends the picture array to the SCSI chip
void send_picture(){
	int i;

	for(i = 0; i < PIC_SIZE; i++){
		send(picture[i]);
	}
}

void programLoop(){	
	while(1){                 
		ram_check();
	
		// if the snapshot button is pressed or continuous capture is on
		// then take a picture
	
		if((SNAPSHOT_BUTTON == 0) || (capture == ON)){
			SNAPSHOT_LED = 0;		// turn on the LED
			send_command('A');		// tell the camera to set the index to 0
			get_response('a'); 

			delay_ms(10);

			send_command('G');		// take the snap shot
			get_response('g');

			delay_ms(500);
		
			send_command('A');		// reset the index to 0
			get_response('a');

			delay_ms(10);
			
			send_command('U');		// upload the picture at index 0
			
			get_picture();
			send_picture();			// send the picture to the SCSI chip

			SNAPSHOT_LED = 1;		// turn off the LED
		}
	}
}

void main(void){ 

	// set up the UART
	UCR = UCR_SETTING;
	UBRR = BAUD_RATE;     

	// set up the two LED's
	DDRD.4 = 1;
	DDRD.5 = 1;
	SNAPSHOT_LED = 1;
	CAPTURE_LED = 1;

	// set up Timer1
	TIMSK = 0x40;		// enable the timer1 compare A interrupt
	TCCR1B = 0b00001010;	// set to reset on match and prescale to 8
	TCNT1 = 0;
	OCR1A = 30000;		// interrupt every 30 ms (.030 s x 8 Mhz / 8 = 30000)

	// enable interrupts
	#asm      
	sei
	#endasm

	// initialize the chip to chip send routine
	send_init();
	programLoop();
}