/*-------------------------------------------------------------------
**
**  Soluciones del examen de Programación de Sistemas y Dispositivos
**  Curso 2017-18, Primera Convocatoria, 23 de enero de 2018
**
**-----------------------------------------------------------------*/

/*-------------------------------------------------------------------
**    Ejercicio 1
**-----------------------------------------------------------------*/

#include <s3c44b0x.h>
#include <common_types.h>
#include <system.h>
#include <uart.h>
#include <timers.h>

void timer0_isr( void ) __attribute__ ((interrupt ("IRQ")));

volatile boolean flag;
volatile char ch;

void main( void )
{
    sys_init();
    uart0_init();
    timers_init();

    flag = FALSE;
    timer0_open_ms( timer0_isr, 20, TIMER_INTERVAL );
    while( 1 )
        if( flag )
        {
            uart0_putchar( ch );
            flag = FALSE;
        }
}

void timer0_isr( void )
{

    if( UFSTAT0 & 0xF )
    {
        ch = URXH0;
        flag = TRUE;
    }

    I_ISPC = BIT_TIMER0;
}

/*-------------------------------------------------------------------
**    Ejercicio 2
**-----------------------------------------------------------------*/

#include <s3c44b0x.h>
#include <s3cev40.h>
#include <common_types.h>
#include <keypad.h>

uint8 keypad_getchar_flag( volatile boolean *flag )
{
    uint8 scancode;

    while( PDATG & 0x2 && !*flag );
    if( *flag ) return 0xff;
    sw_delay_ms( KEYPAD_KEYDOWN_DELAY  );

    scancode = keypad_scan();

    while( !(PDATG & 0x2) && !*flag );
    if( *flag ) return 0xff;
    sw_delay_ms( KEYPAD_KEYUP_DELAY );

    return scancode;
}

/*-------------------------------------------------------------------
**    Ejercicio 3
**-----------------------------------------------------------------*/

#include <common_types.h>
#include <iis.h>

void iis_playFrom( int16 *buffer, uint32 length, uint32 decsegs )
{
    uint32 i;
    int16 ch1, ch2;

    for( i=decsegs*1600*2; i<length/2; )
    {
        ch1 = buffer[i++];
        ch2 = buffer[i++];
        iis_putSample( ch1, ch2 );
    }
}

/*

void iis_playFrom( int16 *buffer, uint32 length, uint32 decsegs )
{
    iis_play( buffer+decsegs*1600*2, length, OFF );
}

*/

/*-------------------------------------------------------------------
**    Ejercicio 4
**-----------------------------------------------------------------*/

#include <common_types.h>
#include <iis.h>

inline void iis_getSampleHalfRate( int16 *ch0, int16 *ch1 )
{
    while( (IISFCON & 0x0F) < 2 );
    *ch0 = IISFIF;
    *ch1 = IISFIF;
    while( (IISFCON & 0x0F) < 2 );
    *ch0 = (IISFIF + *ch0) >> 1;
    *ch1 = (IISFIF + *ch1) >> 1;   
    
}

/*

inline void iis_getSampleHalfRate( int16 *ch0, int16 *ch1 )
{
    int16 ch0aux, ch1aux;

    iis_getSample( &ch0aux, &ch1aux );
    iis_getSample( ch0, ch1 );
    *ch0 = ( ch0aux + *ch0 ) >> 1;
    *ch1 = ( ch1aux + *ch1 ) >> 1;
}

*/