MSP430G2553的硬件IIC

这是www.ti.com上的例程，希望能对你有帮助

//******************************************************************************

//  MSP430G2xx3 Demo - USCI_B0 I2C Master TX single bytes to MSP430 Slave

//

//  Description: This demo connects two MSP430's via the I2C bus. The master

//  transmits to the slave. This is the master code. It continuously

//  transmits 00h, 01h, ..., 0ffh and demonstrates how to implement an I2C

//  master transmitter sending a single byte using the USCI_B0 TX interrupt.

//  ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = ~1.2MHz

//

//                                /|\  /|\

//               MSP430G2xx3      10k  10k     MSP430G2xx3

//                   slave         |    |        master

//             -----------------   |    |  -----------------

//           -|XIN  P1.7/UCB0SDA|<-|---+->|P1.7/UCB0SDA  XIN|-

//            |                 |  |      |                 |

//           -|XOUT             |  |      |             XOUT|-

//            |     P1.6/UCB0SCL|<-+----->|P1.6/UCB0SCL     |

//            |                 |         |                 |

//

//  D. Dang

//  Texas Instruments Inc.

//  February 2011

//   Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10

//******************************************************************************

#include "msp430g2553.h"

unsigned char TXData;

unsigned char TXByteCtr;

void main(void)

{

 WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT

 P1SEL |= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0

 P1SEL2|= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0

 UCB0CTL1 |= UCSWRST;                      // Enable SW reset

 UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master, synchronous mode

 UCB0CTL1 = UCSSEL_2 + UCSWRST;            // Use SMCLK, keep SW reset

 UCB0BR0 = 12;                             // fSCL = SMCLK/12 = ~100kHz

 UCB0BR1 = 0;

 UCB0I2CSA = 0x48;                         // Slave Address is 048h

 UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation

 IE2 |= UCB0TXIE;                          // Enable TX interrupt

 TXData = 0x00;                            // Holds TX data

 while (1)

 {

   TXByteCtr = 1;                          // Load TX byte counter

   while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent

   UCB0CTL1 |= UCTR + UCTXSTT;             // I2C TX, start condition

   __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts

                                           // Remain in LPM0 until all data

                                           // is TX'd

   TXData++;                               // Increment data byte

 }

}

//------------------------------------------------------------------------------

// The USCIAB0TX_ISR is structured such that it can be used to transmit any

// number of bytes by pre-loading TXByteCtr with the byte count.

//------------------------------------------------------------------------------

#pragma vector = USCIAB0TX_VECTOR

__interrupt void USCIAB0TX_ISR(void)

{

 if (TXByteCtr)                            // Check TX byte counter

 {

   UCB0TXBUF = TXData;                     // Load TX buffer

   TXByteCtr--;                            // Decrement TX byte counter

 }

 else

 {

   UCB0CTL1 |= UCTXSTP;                    // I2C stop condition

   IFG2 &= ~UCB0TXIFG;                     // Clear USCI_B0 TX int flag

   __bic_SR_register_on_exit(CPUOFF);      // Exit LPM0

 }

}

建议楼主安装CCSv5 IDE，里头集成了关于IIC的例程代码，目前有13个例程如下图所示。

其中例程i2c_04是master接收数据，例程i2c_05是slave 发送数据