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USCI I2C – Interfacing DS1307 Real Time Clock (RTC)

This part shows another example of I2C implementation using MSP430’s USCI hardware. This time the

I2C device that is connected with a MSP430 is the popular DS1307 real time clock (RTC). This is the

last USCI hardware example.

Code Example

HW_I2C.h

#include <msp430.h>

void I2C_USCI_init(unsigned char address);

void I2C_USCI_set_address(unsigned char address);

unsigned char I2C_USCI_read_byte(unsigned char address);

unsigned char I2C_USCI_read_word(unsigned char address,unsigned char *value,

unsigned char length);

unsigned char I2C_USCI_write_byte(unsigned char address, unsigned char value);

HW_I2C.c

#include "HW_I2C.h"

void I2C_USCI_init(unsigned char address)

{

P1DIR &= ~(BIT6 + BIT7);

P1OUT |= (BIT6 + BIT7);

P1SEL2 |= (BIT6 | BIT7);

P1SEL |= (BIT6 | BIT7);

UCB0CTL1 |= UCSWRST;

UCB0CTL0 = (UCMST | UCMODE_3 | UCSYNC);

UCB0CTL1 = (UCSSEL_2 | UCSWRST);

UCB0BR0 = 20;

UCB0I2CSA = address;

UCB0CTL1 &= ~UCSWRST;

Texas Instruments MSP430 User Manual

Other manuals for Texas Instruments MSP430