I2C mit DS3132 - Peter Fleury I2C implementierung

#include <avr/io.h>

#include <util/delay.h>

#include <i2cmaster.h> 

#define BAUD 9600

#define MYUBRR ((uint16_t) ((F_CPU / ((BAUD) * 16.0)) + .5) - 1)

#define rtc_clock 0x68

// contains what the bluetooth module received

uint8_t data;

void USART_Init(unsigned int ubrr) {

    // set baud rate

    UBRR0H = (unsigned char)(ubrr>>8);

    UBRR0L = (unsigned char)(ubrr);

    // enable receiver, transmitter and interrupts for rx/tx

    UCSR0B = (1<<RXEN0) | (1<<TXEN0) | (1<<RXCIE0) | (1<< TXCIE0);

}

void USART_transmit(char c) {

    while ( !(UCSR0A & (1<<UDRE0)) ) {}

    UDR0 = c;

}

void transmit_char(char c) {

    USART_transmit(c);

    USART_transmit('\r');

    USART_transmit('\n');

}

void send_string(char s[]) {

    int i =0;

    while (s[i] != 0x00) {

        USART_transmit(s[i]);

        i++;

    }

    USART_transmit('\r');

    USART_transmit('\n');

}

// code for two status leds, to signal error and ok states

// please dont look to closely....needs rewriting

#define ERROR_LED_2 PB1

#define ERROR_LED PB0

#define OK_LED PB2

#define ERROR_LED_2_PORT PORTB

#define ERROR_LED_PORT PORTB

#define OK_LED_PORT PORTB

// turn the error led on and keep it on

void error_led_on() {

    ERROR_LED_PORT |= (1 << ERROR_LED);

}

// turn it off

void error_led_off() {

    ERROR_LED_PORT &= ~(1 << ERROR_LED);

}

void error_led2_on() {

    ERROR_LED_2_PORT |= (1 << ERROR_LED_2);

}

// turn it off

void error_led2_off() {

    ERROR_LED_2_PORT &= ~(1 << ERROR_LED_2);

}

// flash the error led, fast

void flash_fast(uint8_t count) {

    for (int n=1; n<=count; n++) {

        error_led_on();

        _delay_ms(300);

        error_led_off();

        _delay_ms(300);

    }

}

// ...normal

void flash_normal(uint8_t count) {

    for (int n=1; n<=count; n++) {

        error_led_on();

        _delay_ms(1000);

        error_led_off();

        _delay_ms(1000);

    }

}

// second led to have more indicator for where we are stuck in the code

void flash_normal_error_led_2(uint8_t count) {

    for (int n=1; n<=count; n++) {

        error_led2_on();

        _delay_ms(1000);

        error_led2_off();

        _delay_ms(1000);

    }

}

// ...slow

void flash_slow(uint8_t count) {

    for (int n=1; n<=count; n++) {

        error_led_on();

        _delay_ms(3000);

        error_led_off();

        _delay_ms(3000);

    }

}

// a third led, can be used to signal ok states

void flash_ok_led(uint8_t count) {

    for (uint8_t n=1; n <= count; n++) {

        OK_LED_PORT |= (1 << OK_LED);

        _delay_ms(1000);

        OK_LED_PORT &= ~(1 << OK_LED);

        _delay_ms(1000);

    }

}

// ---------------------------------- led code end

uint8_t decToBcd(uint8_t val)

{

  return( (val/10*16) + (val%10) );

}

// Convert binary coded decimal to normal decimal numbers

uint8_t bcdToDec(uint8_t val)

{

  return( (val/16*10) + (val%16) );

}

void setTime(uint8_t second, uint8_t minute, uint8_t hour, uint8_t dayOfWeek, 

        uint8_t dayOfMonth, uint8_t month, uint8_t year) {

    flash_normal(1);

    // initialize, taken from peter fleurys i2c example (he wrote the i2c code)

    i2c_init();

    // connect to the device and tell it that we want to write to it

    uint8_t ret;

    //ret = i2c_start(rtc_clock+I2C_WRITE);  // set device address and write mode

    ret = i2c_start(rtc_clock);

    // this line is never reached

    flash_normal(1);

    if ( ret ) {

        flash_normal(3);

        /* failed to issue start condition, possibly no device found */

        i2c_stop();

        // we can issue an error message here if the device failed to respond

     } else {

        flash_ok_led(3);

        // tell the device where we want to write to (address in ram)

        i2c_write(0x00);

        // set time

        i2c_write(decToBcd(second)); // set seconds

        i2c_write(decToBcd(minute)); // set minutes

        i2c_write(decToBcd(hour)); // set hours

        i2c_write(decToBcd(dayOfWeek)); // set day of week (1=Sunday, 7=Saturday)

        i2c_write(decToBcd(dayOfMonth)); // set date (1 to 31)

        i2c_write(decToBcd(month)); // set month

        i2c_write(decToBcd(year)); // set year (0 to 99)    

        i2c_stop();     

    }                    

}

uint8_t result;

typedef struct {

    uint8_t sec;

    uint8_t min;

    uint8_t hour;

    uint8_t weekDay;

    uint8_t date;

    uint8_t month;

    uint8_t year;  

} rtc_t;

rtc_t rtc;

void getTime(void) {

    // receive 1 byte (seconds)

    flash_normal(3);

    uint8_t ret;

    ret = i2c_start(rtc_clock+I2C_WRITE);  // set device address and write mode

    if ( ret ) {

        flash_normal(3);

        /* failed to issue start condition, possibly no device found */

        i2c_stop();

        // we can issue an error message here if the device failed to respond

     } else {

        flash_ok_led(1);

        /* issuing start condition ok, device accessible 

        we can now use i2c_write() to talk to the device*/

        // request second ram adress (tell the chip at what adress we want to start reading)

        // 0x00 = 

        i2c_write(0x00);

        i2c_stop();

        // _rep_start or _start? whats the difference?

        i2c_rep_start(rtc_clock);

        result = i2c_readAck();

        rtc.sec = i2c_readAck();                // read second and return Positive ACK

        rtc.min = i2c_readAck();                 // read minute and return Positive ACK

        rtc.hour= i2c_readAck();               // read hour and return Negative/No ACK

        rtc.weekDay = i2c_readAck();           // read weekDay and return Positive ACK

        rtc.date= i2c_readAck();              // read Date and return Positive ACK

        rtc.month=i2c_readAck();            // read Month and return Positive ACK

        rtc.year =i2c_readNak();             // read Year and return Negative/No ACK

        i2c_stop();

    }

}

int main(void) {

    DDRB |= (1 << ERROR_LED);

    DDRB |= (1 << ERROR_LED_2);

    DDRB |= (1 << OK_LED);

    // test leds to see if they are connected and working

    flash_normal(1);

    flash_normal_error_led_2(1);

    flash_ok_led(1);    

    i2c_init();

    uint8_t count = 0;

    setTime(30,42,21,4,26,11,14);

    while (1) {

        _delay_ms(3000);

        getTime();

        // flash the led for the ammount of seconds

        for (uint8_t n=0; n <= rtc.sec; n++) {

            flash_ok_led(1);

        }

        flash_normal(2);

    }

}