The basic parallel I/O port of single chip microcomputer development

 一、题目

Basically parallelI/O口

二、要求

1、画出实验的流程图

2、编写源程序并进行注释

3、记录实验过程

4、记录程序运行结果截图

三、过程及结果记录

按照思路搭建电路图1如下：

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图1：实验电路图

实现功能：要求当SW1按键被按下后,D1-D8轮流点亮,点亮时间为100ms,When the button stops,Stop the rotation;再次按下后,continue to rotate.

实验过程：

1. 用ProteusBuild the experimental circuit diagram as above.

2. 将实验代码写入文本文档,并保存成asm文件.

3. Right click on the chip,Select Add source files.

4. 将程序进行编译：单击上方工具栏的source,然后build all,将asm文件编译成hex文件

5. 将可执行文件hexwrite to the chip

6. 点击运行仿真,观察仿真结果,如图2~4所示.

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图2：开关断开时,P2 Port all bits are set to1,Diode goes out

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图3：When the button switch is closed,The value of the buffer unit is rotated to the left1,The diodes light up sequentially

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图4：When the button switch is closed,The value of the buffer unit is rotated to the left1,The diodes light up sequentially

基本思路：

• 进行初始化工作,包括设置堆栈指针SP,将P2 Port all bits are set to1,使P2The light-emitting diodes connected to the port are all extinguished.The buffer unit will be displayed（设为20H 单元）初始化为FEH.（i.e. write in the buffer11111110）
•  从P1口读数据,查看P1.0 位,如果P1.0 位为0,Then execute the following loop：Send the value of the display buffer unit toP2 口,调用100ms 延时程序,Rotate the value of the displayed buffer unit to the left1 位,It is sent back to the display buffer unit.如果P1.0 位不为0 The above loop is not executed.
•  重复上一步的操作

The experimental flow chart can be drawn as follows：

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图5：流程图

四、源程序

ORG 0000H      ;在内存的0地址处就强制转到主程序上去,绕过中断程序AJMP MAIN     ;无条件的转移到主程序ORG 0030H      ;从30H开始写程序,The entry to the interrupt routine is skippedMAIN:           MOV SP,#60H		;设置sp栈指针  MOV P2,#0FFH      ;Follow the idea firstP2All values ​​are set1  MOV 20H,#0FEH		 ;Set the display buffer unit address to FEH（11111110）  MOV R5,#8			 ;Set the total number of loops to 8,由R5寄存器控制LIGHTEN:				   SETB P1.0			 ;允许P1.0port to read data,Write before reading1  JNB P1.0,LOOP1		  ;判断p1.0Whether the mouth is0,若为0Indicates that the button was pressed,则执行循环loop1  AJMP L1				  LOOP1:  MOV A,20H				  MOV P2,A              ;The corresponding ones are lit hereLED灯  ACALL DELAY				;调用延时子程序delay,Realize continuous lighting time  MOV A,P2  RL A                      ;Shifts the value of the buffer location one bit to the left  MOV 20H,A					 ;Return the newly obtained value of the buffer unit to the buffer unitL1:DJNZ R5,LIGHTEN			;General loop control statement,共循环8次,Before each loop is the firstR5中的值减1    							 DELAY:         ;延时子程序  MOV R7,#200				  ;Define the outer loop count as 200 DL1:MOV R6,#250			;Define the inner loop as 250     DJNZ R6,$				     DJNZ R7,DL1		;计算延迟时间：（1μs*2*250+2+1）*200+1约等于100ms  RET 						   ;返回主程序  SJMP $         ;Jump to the beginning of the instruction to start execution,So it becomes loop execution,Jump in place,Usually used to wait for an interruptEND	 ;程序结束

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