### PCF8591 Python Code Example 为了实现对PCF8591芯片的操作，在Python环境中通常会创建一个专门的库文件来处理与该硬件交互的具体细节[^1]。 ```python import smbus import time class PCF8591: def __init__(self, address): self.bus = smbus.SMBus(1) self.address = address def read(self, channel): """Read ADC value from a specific analog input.""" if channel not in range(4): raise ValueError("Channel must be between 0 and 3.") # Command byte consists of control bits followed by channel selection. command_byte = 0x40 | (channel << 4) try: self.bus.write_byte(self.address, command_byte) adc_value = self.bus.read_byte(self.address) return adc_value except IOError as e: print(f"Error reading from I2C bus: {e}") return None def write(self, value): """Write DAC output to set an analog voltage level.""" if not 0 <= value <= 255: raise ValueError("Value out of bounds; expected 0-255.") try: self.bus.write_byte_data(self.address, 0x40, int(value)) except IOError as e: print(f"Error writing to I2C bus: {e}") if __name__ == "__main__": pcf = PCF8591(address=0x48) # Default I2C address for PCF8591 is usually 0x48. while True: for ch in range(4): val = pcf.read(ch) print(f"Channel {ch}: {val} ") time.sleep(1) ``` 这段代码定义了一个`PCF8591`类，它封装了通过I²C总线读取模拟输入通道数据以及设置DAC输出的功能。此示例展示了如何初始化设备、配置通信参数，并实现了基本功能方法如`read()`和`write()`。此外还包含了简单的异常处理逻辑以应对可能发生的IO错误情况。