MSP430G2553软件模拟IIC代码

以下是MSP430G2553软件模拟I2C的代码示例，供您参考：

#include <msp430g2553.h>

#define I2C_SDA BIT7
#define I2C_SCL BIT6

void I2C_delay()
{
    __delay_cycles(10); //延时函数，根据实际情况调整
}

void I2C_start()
{
    P1OUT |= I2C_SDA;
    P1OUT |= I2C_SCL;
    I2C_delay();

    P1OUT &= ~I2C_SDA;
    I2C_delay();

    P1OUT &= ~I2C_SCL;
}

void I2C_stop()
{
    P1OUT &= ~I2C_SDA;
    P1OUT |= I2C_SCL;
    I2C_delay();

    P1OUT |= I2C_SDA;
    I2C_delay();
}

void I2C_send_byte(unsigned char data)
{
    unsigned char i;
    for (i = 0; i < 8; i++)
    {
        if ((data & 0x80) == 0x80)
        {
            P1OUT |= I2C_SDA;
        }
        else
        {
            P1OUT &= ~I2C_SDA;
        }
        data <<= 1;
        I2C_delay();

        P1OUT |= I2C_SCL;
        I2C_delay();
        P1OUT &= ~I2C_SCL;
        I2C_delay();
    }

    P1DIR &= ~I2C_SDA; //释放SDA线，准备接收ACK
    I2C_delay();

    P1OUT |= I2C_SCL;
    I2C_delay();
    while (P1IN & I2C_SDA) //等待设备发送ACK
    {
        P1OUT &= ~I2C_SCL;
        I2C_delay();

        P1OUT |= I2C_SCL;
        I2C_delay();
    }
    P1OUT &= ~I2C_SCL;
    I2C_delay();
    P1DIR |= I2C_SDA; //SDA线重新变为输出模式
}

unsigned char I2C_read_byte()
{
    unsigned char i, data = 0;
    P1DIR &= ~I2C_SDA; //SDA线变为输入模式

    for (i = 0; i < 8; i++)
    {
        data <<= 1;
        P1OUT |= I2C_SCL;
        I2C_delay();
        if (P1IN & I2C_SDA)
        {
            data |= 0x01;
        }
        P1OUT &= ~I2C_SCL;
        I2C_delay();
    }

    P1DIR |= I2C_SDA; //SDA线重新变为输出模式，发送ACK
    P1OUT &= ~I2C_SDA;
    I2C_delay();

    P1OUT |= I2C_SCL;
    I2C_delay();
    P1OUT &= ~I2C_SCL;
    I2C_delay();

    return data;
}

int main(void)
{
    WDTCTL = WDTPW + WDTHOLD; //停用看门狗
    P1DIR |= I2C_SDA + I2C_SCL;
    P1OUT |= I2C_SDA + I2C_SCL; //初始化SDA和SCL线为高电平

    I2C_start();
    I2C_send_byte(0x7A); //发送设备地址
    I2C_send_byte(0x00); //发送数据
    I2C_stop();

    __bis_SR_register(LPM0_bits + GIE); //进入低功耗模式，等待中断事件

    return 0;
}

需要注意的是，软件模拟I2C的速度相对硬件I2C较慢，而且对于一些高速I2C设备可能会存在兼容性问题。因此，如果应用场景允许，建议使用硬件I2C模块。