MCP3221 C51代码

MCP3221是一款12位的单通道模数转换器（ADC），适用于C51单片机。下面是一个简单的MCP3221 C51代码示例：

#include <reg51.h>

sbit SDA = P2^0;  // I2C数据线
sbit SCL = P2^1;  // I2C时钟线

void delay(unsigned int time) {
    unsigned int i, j;
    for(i = 0; i < time; i++)
        for(j = 0; j < 10; j++);
}

void I2C_Start() {
    SDA = 1;
    SCL = 1;
    delay(1);
    SDA = 0;
    delay(1);
    SCL = 0;
}

void I2C_Stop() {
    SDA = 0;
    SCL = 1;
    delay(1);
    SDA = 1;
    delay(1);
}

void I2C_Write(unsigned char dat) {
    unsigned char i;
    for(i = 0; i < 8; i++) {
        SDA = (dat & 0x80) >> 7;
        dat <<= 1;
        SCL = 1;
        delay(1);
        SCL = 0;
        delay(1);
    }
    SDA = 1;
    SCL = 1;
    delay(1);
    SCL = 0;
}

unsigned char I2C_Read() {
    unsigned char i, dat = 0;
    SDA = 1;
    for(i = 0; i < 8; i++) {
        dat <<= 1;
        SCL = 1;
        delay(1);
        dat |= SDA;
        SCL = 0;
        delay(1);
    }
    return dat;
}

unsigned int MCP3221_Read() {
    unsigned int result;
    I2C_Start();
    I2C_Write(0x90);  // MCP3221的I2C地址为0x90
    I2C_Stop();
    I2C_Start();
    I2C_Write(0x91);  // 读取MCP3221的数据
    result = (I2C_Read() << 8) | I2C_Read();
    I2C_Stop();
    return result;
}

void main() {
    unsigned int adc_value;
    while(1) {
        adc_value = MCP3221_Read();
        // 处理ADC值
        // ...
    }
}

这段代码实现了通过I2C总线读取MCP3221的ADC值。其中，`I2C_Start`和`I2C_Stop`函数用于发送I2C起始信号和停止信号，`I2C_Write`和`I2C_Read`函数用于写入和读取数据。`MCP3221_Read`函数用于读取MCP3221的ADC值。