MSP430F5529 I2C 程序

#include <msp430.h>
#include "i2c.h"
extern unsigned char RXData,TXData,TXByteCtr,ATXData[2];

void I2C_Init(uint8_t SlaveAddress)
{
P3SEL |= 0x03; // Assign I2C pins to USCI_B0
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
UCB0CTL1 = UCSSEL_2 + UCSWRST+UCTR; // Use SMCLK
UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz
UCB0BR1 = 0;
UCB0I2CSA = SlaveAddress; // Slave Address is 048h
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
UCB0IE |= UCTXIE+UCRXIE+UCSTPIE;
}
void I2C_WriteReg(unsigned char RegAddr, unsigned char Data) //////////涓婁笅灞侫PI闇?瑕佺敤鍒?
{

TXByteCtr = 2; // Load TX byte counter
ATXData[0]=RegAddr;
ATXData[1]=Data;

while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent
UCB0IE |= UCTXIE;
UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition
__bis_SR_register(LPM0_bits + GIE); // Enter LPM0 w/ interrupts
__no_operation();
}


uint8_t I2C_ReadByte() //////////涓婁笅灞侫PI闇?瑕佺敤鍒?
{

while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent
UCB0CTL1 &= ~UCTR;
UCB0IE &=~ UCTXIE;
UCB0CTL1 |= UCTXSTT; // I2C start condition

while(UCB0CTL1 & UCTXSTT); // Start condition sent?
UCB0CTL1 |= UCTXSTP;
return RXData;

}


#pragma vector = USCI_B0_VECTOR
__interrupt void USCI_B0_ISR(void)
{
switch(__even_in_range(UCB0IV,12))
{
case 0: break; // Vector 0: No interrupts
case 2: break; // Vector 2: ALIFG
case 4: break; // Vector 4: NACKIFG
case 6: break; // Vector 6: STTIFG
case 8:
UCB0IFG &= ~UCSTPIFG; // Clear stop condition int flag
__bic_SR_register_on_exit(LPM0_bits); // Exit LPM0 if data was transmitted
break; // Vector 8: STPIFG
case 10:
RXData=UCB0RXBUF;
// UCB0CTL1 |= UCTXNACK+UCTXSTP;
UCB0IFG &= ~UCRXIFG;

__bic_SR_register_on_exit(LPM0_bits);
break; // Vector 10: RXIFG
case 12: // Vector 12: TXIFG
if (TXByteCtr) // Check TX byte counter
{
UCB0TXBUF = ATXData[2-TXByteCtr]; // Load TX buffer
TXByteCtr--; // Decrement TX byte counter
}
else
{
UCB0CTL1 |= UCTXSTP; // I2C stop condition
UCB0IFG &= ~UCTXIFG; // Clear USCI_B0 TX int flag
__bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
}
break;
default: break;
}
}