#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include <util/delay.h>
#include <stdint.h>
#include <stdbool.h>

#include "utils.h"

// Change to the image you want:
#include "image_globus32.h"


/**
 *                   +--u--+
 *             RST --|     |-- Vcc
 *   TRIGGER : PB3 --| t13 |-- PB2 : CLOCK   ->
 *      N.C. : PB4 --|     |-- PB1 : STROBE  -> to chained 74HC4094's
 *             GND --|     |-- PB0 : DATA    ->
 *                   +-----+
 *
 * TRIGGER is connected to ground by spring switch
 * that gets activated at start of swing to right.
 * (It's a metal contact with weight)
 *
 * LEDs are connected to 74HC4094 outputs by anodes.
 * To use cathodes, invert byte in sendByte function.
 */


// timing config (microseconds)
#define LIGHT_US 1500
#define GAP_US 200



// pins config
#define PIN_DATA	PB0
#define PIN_STROBE	PB1
#define PIN_CLOCK	PB2
#define PIN_TRIGGER	PB3


#define increment_wrap(var, max)  if ((var) >= (max)) { (var)=0; } else { (var)++; }
#define decrement_wrap(var, max)  if ((var) > 0) { (var)--; } else { (var)=(max); }


/** Initialize IO ports. */
void init_io(void) SECTION(".init8");

void init_io(void)
{
	// set output pins
	DDRB	= _BV(PIN_DATA) | _BV(PIN_STROBE) | _BV(PIN_CLOCK);

	// pullups
	PORTB	= _BV(PIN_TRIGGER);


	// initialize the timer

	TCCR0B = _BV(CS00) | _BV(CS01);  // prescaler 0
	OCR0A = 150;  // interrupt every 1 ms
	sbi(TIMSK0, OCIE0A);

	// initialize external interrupt

	PCMSK = _BV(PCINT3);
	sbi(GIMSK, PCIE);  // pin change interrupt enable

	sei();
}


volatile bool want_stop = 1;
volatile uint8_t col_start = 0;
volatile uint8_t ms_counter = 0;


/** timer 0 interrupt vector */
ISR(PCINT0_vect)
{
	want_stop = 1; // request to stop cycle
}


/** timer 0 interrupt vector */
ISR(TIM0_COMPA_vect)
{
	if(++ms_counter >= 150) {
		ms_counter = 0;
		increment_wrap(col_start, COLS - 1);
	}
}


/** send one byte into registers */
void sendByte(uint8_t b)
{
	for(uint8_t i=0; i<8; i++) {
		setBit(PORTB, PIN_DATA, getBit(b, i));

		// pulse
		busPulse(PORTB, PIN_CLOCK);
	}
}


/** send STROBE pulse */
#define display() busPulse(PORTB, PIN_STROBE)

/**
 * Main function
 */
int main(void)
{
	while(1) {

		while(1 == getBit(PINB, PIN_TRIGGER)); // wait for LOW on trigger
		_delay_ms(3); // debounce delay
		while(0 == getBit(PINB, PIN_TRIGGER)); // wait for trigger to be released
		_delay_ms(3); // delay before start of image
		want_stop = 0; // clear flag

		uint8_t col = col_start;
		for(uint8_t i = 0; i < COLS; i++) {
			if (want_stop) break;

			increment_wrap(col, COLS - 1);

			// +++ light +++

			for(int8_t row=ROWS-1; row>=0; row--) {
				uint8_t b = pgm_read_byte(&image[col][row]);
				sendByte(b);
			}

			display();
			// Duration of pixel
			_delay_us(LIGHT_US);

			// +++ dark +++

			for(int8_t row=ROWS-1; row>=0; row--)
				sendByte(0);

			display();
			// Delay between pixels
			// (remove to get continuous lines)
			_delay_us(GAP_US);
		}
	}
}