重写这句话本次研究AD转换模块用到的芯片是PCF8951它有4路8位AD输入属于逐次比较型内含采样保持电路1路8位输出内含有ADC数据寄存器。意思是芯片内有四个通道所以分为以下程序的四种情况。 Case0是用来读取8951芯片第一通道所采集的到模拟量的值；0x41是控制发送的字节；IRcvBytePCF8591是用来接收读取AD转换的数据；本设计在AD模块中利用芯片PCF8951输入和输出都进行了

The PCF8951 chip is used in the AD conversion module, which has 4 channels of 8-bit A/D input and is of the successive comparison type. It includes a sampling and holding circuit and 1 channel of 8-bit output with an ADC data register. The chip has four channels, which are represented by four different cases in the program. Case0 is used to read the analog value collected by the first channel of the 8951 chip, with 0x41 controlling the byte sent and IRcvByte(PCF8591) used to receive the AD conversion data. The design uses the PCF8951 chip for voltage-sustaining sampling during input and output in the AD module, which involves two internal samplings. Therefore, the final output voltage needs to be IRcvByte(PCF8591)*2 to ensure the input and output data are the same and the accuracy of the data is guaranteed. ADC is used to store the output data of each channel. The following channels are similar. The last if statement in the program refers to manual mode operation