利用msp430g2553通过i2协议读取bmp180的测量的气压数据并通过串口在pc端显示出来,请给出具体程序及详细的注释 (程序适用于Code Composer Studio 12.3.0)

以下是一个简单的程序，用于读取BMP180的气压数据并通过UART发送到PC端。注释中会解释每个步骤的作用。

#include <msp430.h>
#include <stdio.h>

// 定义BMP180的I2C地址
#define BMP180_ADDR 0x77

// 定义BMP180的寄存器地址
#define BMP180_CTRL_REG 0xF4
#define BMP180_TEMP_REG 0x2E
#define BMP180_PRESSURE_REG 0x34

// 定义串口参数
#define BAUDRATE 9600
#define CLK_FREQ 1000000

// 初始化串口
void initUART() {
    P1SEL |= BIT1 + BIT2; // P1.1 = RXD, P1.2=TXD
    P1SEL2 |= BIT1 + BIT2; // P1.1 = RXD, P1.2=TXD
    UCA0CTL1 |= UCSSEL_2; // SMCLK
    UCA0BR0 = CLK_FREQ / BAUDRATE;
    UCA0BR1 = 0;
    UCA0MCTL = UCBRS2 + UCBRS0; // Modulation UCBRSx = 5
    UCA0CTL1 &= ~UCSWRST; // Initialize USCI state machine
}

// 向BMP180写入一个字节的数据
void writeByte(unsigned char addr, unsigned char data) {
    // 发送START信号
    UCB0CTL1 |= UCTR + UCTXSTT;

    // 等待START信号发送完毕
    while(!(IFG2 & UCB0TXIFG));

    // 发送设备地址和寄存器地址
    UCB0TXBUF = BMP180_ADDR << 1;
    while(!(IFG2 & UCB0TXIFG));
    UCB0TXBUF = addr;
    while(!(IFG2 & UCB0TXIFG));

    // 发送数据
    UCB0TXBUF = data;
    while(!(IFG2 & UCB0TXIFG));

    // 发送STOP信号
    UCB0CTL1 |= UCTXSTP;
    while(UCB0CTL1 & UCTXSTP);
}

// 从BMP180读取一个字节的数据
unsigned char readByte(unsigned char addr) {
    unsigned char data;

    // 发送START信号
    UCB0CTL1 |= UCTR + UCTXSTT;

    // 等待START信号发送完毕
    while(!(IFG2 & UCB0TXIFG));

    // 发送设备地址和寄存器地址
    UCB0TXBUF = BMP180_ADDR << 1;
    while(!(IFG2 & UCB0TXIFG));
    UCB0TXBUF = addr;
    while(!(IFG2 & UCB0TXIFG));

    // 发送RESTART信号
    UCB0CTL1 &= ~UCTR;
    UCB0CTL1 |= UCTXSTT;
    while(!(IFG2 & UCB0TXIFG));

    // 发送设备地址，读取数据
    UCB0TXBUF = (BMP180_ADDR << 1) | 0x01;
    while(!(IFG2 & UCB0TXIFG));

    // 接收数据
    while(!(IFG2 & UCB0RXIFG));
    data = UCB0RXBUF;

    // 发送STOP信号
    UCB0CTL1 |= UCTXSTP;
    while(UCB0CTL1 & UCTXSTP);

    return data;
}

// 从BMP180读取一个16位的数据
unsigned int readWord(unsigned char addr) {
    unsigned int data;

    // 发送START信号
    UCB0CTL1 |= UCTR + UCTXSTT;

    // 等待START信号发送完毕
    while(!(IFG2 & UCB0TXIFG));

    // 发送设备地址和寄存器地址
    UCB0TXBUF = BMP180_ADDR << 1;
    while(!(IFG2 & UCB0TXIFG));
    UCB0TXBUF = addr;
    while(!(IFG2 & UCB0TXIFG));

    // 发送RESTART信号
    UCB0CTL1 &= ~UCTR;
    UCB0CTL1 |= UCTXSTT;
    while(!(IFG2 & UCB0TXIFG));

    // 发送设备地址，读取数据
    UCB0TXBUF = (BMP180_ADDR << 1) | 0x01;
    while(!(IFG2 & UCB0TXIFG));

    // 接收数据
    while(!(IFG2 & UCB0RXIFG));
    data = UCB0RXBUF << 8;
    while(!(IFG2 & UCB0RXIFG));
    data |= UCB0RXBUF;

    // 发送STOP信号
    UCB0CTL1 |= UCTXSTP;
    while(UCB0CTL1 & UCTXSTP);

    return data;
}

void main(void) {
    WDTCTL = WDTPW + WDTHOLD; // 禁用看门狗

    // 初始化I2C
    P1SEL |= BIT6 + BIT7;
    P1SEL2 |= BIT6 + BIT7;
    UCB0CTL1 |= UCSWRST;
    UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;
    UCB0CTL1 = UCSSEL_2 + UCSWRST;
    UCB0BR0 = 10;
    UCB0BR1 = 0;
    UCB0CTL1 &= ~UCSWRST;

    initUART(); // 初始化串口

    // 读取BMP180的厂商ID，用于检测BMP180是否连接成功
    unsigned int id = readByte(0xD0) << 8;
    id |= readByte(0xD1);

    if(id != 0x55) { // 厂商ID应为0x55
        printf("BMP180 not found\r\n");
        return;
    }

    // 读取BMP180的温度，并计算出实际温度值
    writeByte(BMP180_CTRL_REG, BMP180_TEMP_REG);
    __delay_cycles(5000); // 等待BMP180完成温度测量
    unsigned int ut = readWord(0xF6);
    long x1 = (ut - 0xAC6) * 160 / 32768;
    long x2 = 160 * 7 * 2048 / 16000;
    long b5 = x1 + x2;
    long t = (b5 + 8) / 16;

    // 读取BMP180的气压，并计算出实际气压值
    writeByte(BMP180_CTRL_REG, BMP180_PRESSURE_REG + (3 << 6));
    __delay_cycles(30000); // 等待BMP180完成气压测量
    unsigned char msb = readByte(0xF6);
    unsigned char lsb = readByte(0xF7);
    unsigned char xlsb = readByte(0xF8);
    long up = ((msb << 16) + (lsb << 8) + xlsb) >> (8 - 3);
    long b6 = b5 - 4000;
    x1 = (b6 * b6) >> 12;
    x1 *= 16;
    x2 = 160 * b6 / 2048;
    long x3 = x1 + x2;
    long b3 = (((long)readWord(0xB4)) * x3 + 2) >> 2;
    x1 = 160 * b6 / 2048;
    x2 = (b6 * b6) >> 11;
    x2 *= 4;
    x3 = (x2 >> 12) * 3755;
    x2 = (x2 * b6) >> 12;
    long b4 = readWord(0xB6);
    long b7 = ((long)(up - b3)) * (50000 >> 3);
    long p;
    if(b7 < 0x80000000) {
        p = (b7 * 2) / b4;
    } else {
        p = (b7 / b4) * 2;
    }
    x1 = (p >> 8) * (p >> 8);
    x1 = (x1 * 3038) >> 16;
    x2 = (-7357 * p) >> 16;
    p += (x1 + x2 + 3791) >> 4;

    printf("Temperature: %ld.%ld C\r\n", t / 10, t % 10);
    printf("Pressure: %ld Pa\r\n", p);
}

注意：这个程序只是一个示例，实际应用中需要根据具体情况进行修改。例如，需要根据实际的CLK_FREQ和BAUDRATE值来计算正确的UBR值。另外，读取BMP180的气压数据需要进行一系列复杂的计算，可能需要使用浮点数和更高精度的整数计算。