MSP430学习的第一个模拟I2C程序

#include <msp430.h>
unsigned char I2CBUF;
unsigned char checkbit;
#define SCL_H   (P10OUT |= BIT2)      // P10.2为SCL
#define SCL_L   (P10OUT &= ~BIT2)
#define SDA_H   (P10OUT |= BIT1)     //p10.1为SDA
#define SDA_L   (P10OUT &= ~BIT1)
#define SDA_OUT  (P10DIR |= BIT1)
#define SDA_IN  (P10DIR &= ~ BIT1)
void I2C_Start(void)    //I2C开始信号
{
 SDA_OUT;
 SCL_L;
 SDA_H;
 __delay_cycles(5);
 SCL_H;
 __delay_cycles(5);
 SDA_L;
 __delay_cycles(5);
 SCL_L;
 __delay_cycles(5);
}
unsigned char testACK(void) {
 SDA_IN;
 __delay_cycles(5);
 SCL_H;
 __delay_cycles(5);
 checkbit = (P10IN & BIT1) >> 4;