/* Copyright © 2020 tyrolyean
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "avr.h"
#include "structures.h"
#include "16550.h"
#include "dac.h"
#include "interrupt.h"
#include "sound.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>


/* Included early on the prevent the watchdog from killing the already killed
 * microcontroller because of init delay 
 */

uint8_t mcusr_mirror __attribute__ ((section (".noinit")));
void get_mcusr(void) \
  __attribute__((naked)) \
  __attribute__((section(".init3")));

void get_mcusr(void)
{
  mcusr_mirror = MCUSR;
  MCUSR = 0;
  wdt_disable();
}

/* Function used to be more complicated, still remains for readability reasons
 */

void set_addr(uint8_t addr){

	ADDR_REG = addr;
	return;
}

void reset_modules(){

	/* Setup Data Direction Registers and populate with sane default 
	   values */
	DATA_DDR_REG = 0xFF; /* Data Bus */
	ADDR_DDR_REG = 0xFF; /* Address Bus */
	CTRL_DDR_REG= 0xFF; /* Control Bus */
	ADDR_REG = 0x00;
	DATA_REG = 0x00;
	CTRL_REG = 0x00;

	/* Cleanly reset the dac uart */
	CTRL_REG |= (1<<WR_SHIFT) | (1<<RD_SHIFT) | (1<<CS_DAC_SHIFT) | 
		(1<<MR_SHIFT) | (1<<CS_UART_SHIFT);

	
	_delay_us(100);
	CTRL_REG &= ~(1<<MR_SHIFT);

	return;
}

int routine();
int main(){
	/* Disable interrupts during initialisation phase */	
	cli();
	reset_modules();
	init_uart();
	init_interrupts();
	current_track = (const struct tone_t (**)) &lonely_road;
	sei();
	/* Enable the hardware watchdog. In case the microcontroller fails to 
	 * finish it's task within the specified time, the watchdog will reset
	 * the atmel cookie.
	 */
	wdt_enable(WDTO_1S);	
        
	while(1){
		wdt_reset();
		routine();
        }

        return 0;
}

int routine(){
	uint8_t received = read_from_uart(UART_REG_LSR);
	if(received & 0x01){
		received = read_from_uart(UART_REG_TXRX);
		write_to_uart(UART_REG_TXRX,received);
	}
	routine_dac();
        return 0;
}