说明：  文件名称: A/D实验--采样、存储和显示实验.ASM 文件标识: none 适用器件: 89C51 ①ADC0809的片选CS1连A15，RAM6116的片选CS3连A14。 ②要求在ADC0809的输入端加上不同的模拟信号，通过键盘输入ADC0809的通道号并启动A/D转换， 采集N个（如N=256）数据存入外部RAM中，打开XDATA窗口，检查实验结果。 注意：①在进行A/D采样前，应先检查ADC0809的参考电压是否正确。 （要求ADC0809的参考电压值Vref = +5V，用万用表观察ADC0809芯片的12脚电压值。 若不对，可调节实验板上的电位器W1来改变A/D的参考电压值）。 ②实验板上电位器W2可调节校准信号的值（注：实验板上校准信号已经连到通道7的IN7上）。 ③将AD采样的值送到RAM6116的0b000H开始单元中，同时在数码管上显示出来。
(File Name: A/D experiment- sampling, storage and display of experimental ASM File identification: none Applicable to devices: 89C51 ① the ADC0809 s chip select CS1 with A15-, A14, RAM6116 chip select CS3 even. The ② requirements with different analog signal input of the ADC0809, and start the channel number of the keyboard to enter the ADC0809 A/D converter, Acquisition of N (eg, N = 256) data are stored in external RAM, open the the XDATA window, check the experimental results. Note: ① The carrying out A/D sampling, you should first check ADC0809 reference voltage is correct. (For the ADC0809 reference voltage value Vref =+5 V, to observe the ADC0809 chip 12-pin voltage with a multimeter. If you are right, the experimental board adjustable potentiometer W1 to change the A/D reference voltage value). ② The board potentiometer W2 to adjust the value of the calibration signal (Note: The experimental on-board calibration signal is connected to channel 7 IN7). (3) the value of th)