carlhako

#include <stdio.h>
#include <stdlib.h>
#include <avr/io.h>

#define CE  PD4     //definitions
#define SCLK  PD2
#define IO  PD3

#define READ 1
#define WRITE 0

// 0x80 seconds write
// 0x81 seconds read
// 0x82 minutes write
// 0x83 minutes read
// 0x84 hour write
// 0x85 hour read
// 0x86 date write
// 0x87 date read
// 0x88 month write
// 0x89 month read
// 0x90 trick charger write
// 0x91 trickle charger read
// 0x8A day write
// 0x8B day read
// 0x8C day write
// 0x8D day read
// 0x8E write protect bit write

void reset(void);       //define the functions
void send(unsigned char);
unsigned char read(void);
void write_byte(unsigned char,unsigned char);
unsigned char read_byte(unsigned char);
unsigned char seconds(unsigned char,unsigned char);
unsigned char minutes(unsigned char,unsigned char);
unsigned char hours(unsigned char, unsigned char);
unsigned char get_day(unsigned char, unsigned char);
void rtc_init(void);
unsigned char get_seconds(void);

void trickle() {
    reset();
    send(0x90); // tell ds1302 what we want to read/write
    send(0xA9); // turn on trickle charger, 1 diode, 2kohm resistor.
}

void rtc_init() {
    unsigned char tmp; // temp variable
    unsigned char tmp2; // temp variable
    reset();
    send(0x8E); // tell ds1302 what we want to read/write
    send(0x00); // turn off write protect

    reset(); // read seconds then write them back. this gets the clock ticking
    send(0x81);
    tmp = read();
    //tmp &= ~(1<<7);
    reset();
    send(0x80);
    send(tmp);

    reset(); // read hours and make sure mode is on 24hour
    send(0x85);
    tmp = read();
    tmp2 = (tmp & (1<<7));
    if (tmp2) {
        reset();
        send(0x84);
        tmp &= ~(1<<7);
        send(tmp);
    }

}


unsigned char write_seconds(unsigned char BYTE) {
    reset(); // reset pins ready for communication
    send(0x80); //tell ds1302 what we want to read/write
    if (BYTE > 0x09) {
        unsigned char tmp; // temp variable
        tmp = BYTE / 0x0A; // copy tens of minutes to tmp
        BYTE %= 0x0A; // remove tens of minutes from BYTE
        BYTE |= (tmp<<4); //move tens of minutes across 4 bytes
    }
    send(BYTE); // write BYTE
}

unsigned char read_seconds(unsigned char units) {
    reset(); // reset pins ready for communication
    unsigned char tmp; // temp variable
    send(0x81); // tell ds1302 what we want to read minutes
    tmp = read(); // read byte previously requested
    if (units == 1) tmp = (tmp & 0x0F); //  grab first 4 bits
    if (units == 10) tmp = ((tmp & 0x70) >> 4); // grab bits 5-7 and shift right
    return tmp;
}

unsigned char write_minutes(unsigned char BYTE) {
    reset(); // reset pins ready for communication
    send(0x82); //tell ds1302 what we want to read/write
    if (BYTE > 0x09) {
        unsigned char tmp; // temp variable
        tmp = BYTE / 0x0A; // copy tens of minutes to tmp
        BYTE %= 0x0A; // remove tens of minutes from BYTE
        BYTE |= (tmp<<4); //move tens of minutes across 4 bytes
    }
    send(BYTE); // write BYTE
}

unsigned char read_minutes(unsigned char units) {
    reset(); // reset pins ready for communication
    unsigned char tmp; // temp variable
    send(0x83); // tell ds1302 what we want to read minutes
    tmp = read(); // read byte previously requested
    if (units == 1) tmp = (tmp & 0x0F); //  grab first 4 bits
    if (units == 10) tmp = ((tmp & 0x70) >> 4); // grab bits 5-7 and shift right
    return tmp;
}

void write_hours(unsigned char BYTE) {
    reset(); // reset pins ready for communication
    send(0x84); //tell ds1302 what we want to read/write
    if (BYTE > 0x09) {
        unsigned char tmp; // temp variable
        tmp = BYTE / 0x0A; // copy tens of minutes to tmp
        BYTE %= 0x0A; // remove tens of minutes from BYTE
        BYTE |= (tmp<<4); //move tens of minutes across 4 bytes
    }
    send(BYTE); // write BYTE
}

unsigned char read_hours(unsigned char units) {

    reset(); // reset pins ready for communication
    unsigned char tmp; // temp variable
    send(0x85); // tell ds1302 what we want to read minutes
    tmp = read(); // read byte previously requested
    if (units == 1) tmp = (tmp & 0x0F); //  grab first 4 bits
    if (units == 10) tmp = ((tmp & 0x70) >> 4); // grab bits 5-7 and shift right
    return tmp;
}

unsigned char day(unsigned char RW, unsigned char BYTE) {
    reset(); // reset pins ready for communication
    send(0x8D); // send ds1302 request for data
    if (RW) {
        unsigned char day; // temp variable
        day = read(); // read byte previously requested
        day = (day & 0x07); // grab first 3 bits
        return day;
    } else {
        send(BYTE);
    }
}

void send(unsigned char W_Byte) //writes the W_Byte to the DS1302

{
    unsigned char i;
    //DDRB = 0xFF;
    DDRD |= ( (1<<IO) | (1<<SCLK) | (1<<CE) ); // set all 3 pins to output

    for(i = 0; i < 8; i++)
    {
        //cbi(PORTD,io);
        PORTD &= ~(1<<IO); // set IO to high
        if(W_Byte &0x01) // compare bit 0, if high set IO to high
        {
            //sbi(PORTD,io);
            PORTD |= (1<<IO); // set IO to high
        }
        //sbi(PORTD,clk);
        PORTD |= (1<<SCLK);
        //delay_ms(1);
        //cbi(PORTD,clk);
        PORTD &= ~(1<<SCLK);
        //delay_ms(1);
        W_Byte >>=1;
    }

}

unsigned char read_byte(unsigned char w_byte)   //read the byte with register w_byte
{
    unsigned char temp;
    reset();
    send(w_byte);
    temp = read();
    //cbi(PORTD,rst);
    //cbi(PORTD,clk);
    PORTD &= ~(1<<CE);
    PORTD &= ~(1<<SCLK);
    return temp;
}

void reset(void)        //sets the pins to begin and end the ds1302 communication
{
    DDRD |= (1<<CE);  // set as output
    PORTD &= ~(1<<SCLK); // set SCLK low
    PORTD &= ~(1<<CE); // set CE low
    PORTD |= (1<<CE); // set CE high
}

unsigned char read(void)        //reads the ds1302 reply
{
    unsigned char i;
    unsigned char R_Byte, TmpByte;
    R_Byte = 0x00;

    // initiate communication
    DDRD |= (1<<IO); //set IO to output
    PORTD &= ~(1<<IO); //set IO low
    DDRD &= ~(1<<IO); // set IO to input

    for(i = 0; i < 8; i++) //loop 8 times to read whole byte
    {
        TmpByte = 0; // clear TmpByte
        //if(bit_is_set(PINB,io))
        if (PIND & (1<<IO)) // if IO is high set TmpByte to 1
            TmpByte = 1;

        TmpByte <<= 7; // shift TmpByte to 7th
        R_Byte >>= 1; // shift all of R_Byte to the right 1 to make room
        R_Byte |= TmpByte; // |= to copy byte across if its set to 1

        PORTD |= (1<<SCLK); //set SCLK to high
        PORTD &= ~(1<<SCLK); // set SCLK to low
    }
    return R_Byte;
}