/*
 * File:   spi.c
 * Author: kubalik
 *
 * Created on 25. ledna 2016, 16:43
 */



#include "p33EV32GM002.h"




//  je to v C:\Program Files (x86)\Microchip\xc16\v1.24\support\dsPIC33E\h
//  od radky 8852 je definovani tech TRIS
// dale si udelejte CntrlF a hledejet ve file *.h
//  linker script najdeme v 
// C:\Program Files (x86)\Microchip\xc16\v1.25\support\dsPIC33E\gld



/*  nasledujici makra nastavuji oscilator
 * hledame v header file 
 *      * Macros for setting device configuration registers  
 *  pin OSC1 jako I/O pin
 * vypinaji Watchdog - opet se podivejte do header file, co vsecno se da nastavit
 *  */
_FOSCSEL(FNOSC_FRC)
_FOSC(OSCIOFNC_ON & IOL1WAY_OFF)
_FWDT(FWDTEN_OFF)


void send_to_SPI(unsigned int value);

/*
 * 
 */
int main() {





    TRISA = 0x0;
    //  zapisujeme do celeho registru najednou


    TRISB = 0x00;
    PORTB = 0;
    PORTA = 0;

    ANSELB = 0;
    ANSELA = 0;

    /*    TIMER T2   
   
     *    T2CON  1X1- ---- -010 0-0- 
     *           | |        ||| | |
     *           | |        ||| | internal clock - FRC oscil  F je 7.37 / 2
     *           | |        ||| T32 - mame 16bitoc\ve citace
     *           | |        ||| 
     *           | |        |TCKPS   10 - delime 64 u preddelicky    
     *           | |        TGATE je vypnuto 
     *           | TSIDLE pracujeme i v idle stavu - to je ted dost jedno
     *           TON   citac zapnut
     * 
     *  chceme periodu 0.5 sec - 2 Hz
     *  do citace leze  7.37 / 2 = 3.685MHz  = 3685000 Hz
     *     na vystupu chceme 2 Hz, takye delime celkem  3685000 / 2 =  1842500 krat
     *  tento delici pomer se posklada z delicky a vlastniho citace
     *  delicka deli 64, na citac tedy zbyva  1842500 / 64 =   28346,15384
     *  do registru PR vlozime  28346
     *        */



    PR2 = 28346;
    T2CON = 0xA020;

    
    SPI1STAT = 0x0000;      //  modul zatim nechavame vzpnuty
   
    SPI1CON1 = 0x0520;      // 0000 0101 0010 0000
    
    SPI1CON2 = 0 ;
    
    SPI1STATbits.SPIROV = 0;     // 3. Clear the SPIROV bit (SPIxSTAT<6>).
    SPI1STATbits.SPIEN  = 1;     // 4. Enable SPI operation by setting the SPIEN bit (SPIxSTAT<15>).

    /*  povoluji preruseni  od citace  */
    IEC0bits.T2IE = 1;
    IEC0bits.SPI1IE=1;      //povoleni preruseni od SPI1

    
    
    /*  globalni povoleni preruseni, tohle se musi povolit, 
     * jinak nebude zadne preruseni krome TRAP   */
    INTCON2bits.GIE = 1;

    while (1) {

        asm(" btg PORTA, #0 ");
        asm(" btg PORTA, #1 ");
        asm(" btg PORTA, #2 ");

    }

    return 0;
}





void __attribute__((interrupt, auto_psv)) _T2Interrupt(void)  {
      IFS0bits.T2IF = 0;
      
      send_to_SPI(0x1234);
}






void __attribute__((interrupt, auto_psv)) _SPI1Interrupt(void)  {
      IFS0bits.SPI1IF = 0;
      /* a tady dal vsechno to, co se ma udelat po odvysilani znaku po SPI   */
      
}





void send_to_SPI(unsigned int value){
    unsigned int a,cteni;
    a=value;      
    cteni=SPI1BUF;      //prectem at muzem vysiliat
    SPI1BUF=a;          // 5. Write the data to be transmitted to the SPIxBUF register
}