#include <iom128.h>
#include <inavr.h>

//Program configuration
//#define ISR_PROCESSING
#define PTR_ACCESS

#define LED_SEG PORTE
#define LED_SEG_DIR DDRE
#define LED_DG PORTB
#define LED_DG_DIR DDRB

#define DV_480Hz 15
#define DV_DEMO  40
#define DV_NEXT  13

#define DEC_OFF 0x3F
#define DISP_MAX 6
#define LED_BLANK 15

typedef union TRQ {
	//Access to entire byte
	unsigned char c;
	struct {
		unsigned char f_tck : 1;
		//other flags can be defined
		unsigned char not_used : 7;
	};
} TRQ;

//Decoding table based on CD4056 -> '0123456789LHPA- '
__flash unsigned char BCD_2_LED[] = {
	0xDE, 0x82, 0xEC, 0xE6,
	0xB2, 0x76, 0x7E, 0xC2,
	0xFE, 0xF6, 0x1C, 0xBA,
	0xF8, 0xFA, 0x20, 0x00 };

__flash unsigned char DEC_1_OF_6[] =
    {0xFE, 0xFD, 0xFB, 0xF7, 0xEF, 0xDF};

//Global variables
unsigned char disp[6] = {0,0,0,0,0,0};
unsigned char cur_disp;
unsigned char dv_demo = DV_DEMO;
unsigned char dv_next = DV_NEXT;
__no_init unsigned char idx;
#define UPDATE_DISP_RQ 0x01
volatile TRQ rq;

void InitDevices()
{
    LED_DG = 0xFE;
    LED_DG_DIR = 0xFF;
    LED_SEG_DIR = 0xFF;
    //Prescaler fclk / 1024 = 7200Hz
    //Prescaler for T0 is different than for T1,T2,T3
    OCR0 = DV_480Hz - 1;
    TCCR0 = (1 << WGM01) | (1 << CS02) | (1 << CS01) | (1 << CS00);
    TIMSK = (1 << OCIE0);
    __enable_interrupt();
}

void DispDemo()
{
unsigned char i;
    if(--dv_next)
    {
        //Johnson counter
        for(i=5; i;  i--)
            disp[i] = (disp[i] & 0xFE) | (disp[i-1] & 0x01);
        disp[0] = (disp[0] & 0xFE) | (~disp[5] & 0x01);
        return;
    }
    dv_next = DV_NEXT;
    //Shift display content
    for(i=5; i;  i--)
    {
        disp[i] = (disp[i] & 0x01) | (disp[i-1] & 0xFE);
    }
    //New pattern generation
    if(idx & 0x10)
    {
        disp[0] = BCD_2_LED[LED_BLANK];
    }
    else
    {
        disp[0] = BCD_2_LED[idx];
    }
	//Take care for operator precedence
    if((++idx) == 0x16) idx = 0;
}

#pragma vector = TIMER0_COMP_vect
__interrupt void T0_COMP_ISR()
{
    LED_DG |= DEC_OFF;
    LED_SEG = disp[cur_disp];
    LED_DG = DEC_1_OF_6[cur_disp];
    if((++cur_disp) == DISP_MAX) cur_disp = 0;
    if(--dv_demo) return;
    dv_demo = DV_DEMO;
    #ifdef ISR_PROCESSING
    DispDemo();
    #else
	rq.f_tck = 1;
    #endif

}

void main()
{
    idx = 0;
    cur_disp = 0;
    //dv_next = DV_NEXT;
    //dv_demo = DV_DEMO;
    InitDevices();
    while(1)
    {
        #ifndef ISR_PROCESSING
        if(rq.f_tck)
        {
            rq.f_tck = 0;
            DispDemo();
        }
        #endif
    }
}