单片机试题及答案 3.docx

1、单片机试题及答案 3单片机试题及答案（Single chip examination questions and answers）AFill in the blanks (1 points per minute, 20 points)1. Monolithic microcomputer consists of CPU, memory and three parts.2, in the MCS-51 system, when the signal is valid, it means that the signal is sent out stably from the P0 port.3,

2、access to 8031 pieces of external data memory using the addressing mode.4, accumulator (A) =80H, execute instruction ADD A, #83H, carry bits C=.5, instruction LCALL 37B0H, the first address in 2000H, the completion of the operation is into the stack, sent to PC.6, MCS-51 interrupt source, 2 interrup

3、t priority, priority by the software to fill in the special function register IP to choose.7, assembly language and two basic instructions.In 8, addressing mode, using A as index registers, or to register.9, interrupt request signal trigger and trigger two trigger modes10, use the serial port extend

4、ed parallel port, serial interface mode should be.11, 74LS273 is usually used as a simple interface extension, while 74LS244 is often used as a simple interface extension.12, MCS-51 parallel I/O port information and two kinds of reading method, read - modify - write operation is for parallel I/O por

5、t of the latch.13, three important indexes of A/D converter are, and sum up.Two, choose a question (choose a correct answer from the alternative answer, and write the code in parentheses. 1 points for each question, 10 points1. The language that computers can recognize is ()(A) assembly language (B)

6、 natural language (C) machine language (C) high-level language2. When the MCS-51 chip is used to expand memory chips, the 4 I/O ports are used as data buses(A) P0 and P2 mouth (B) P0 mouth (C) P2 and P3 mouth (D) P2 mouth3, at least one () of the interrupt service program(A) transfer instruction (B)

7、 transfer instruction (C) addition instruction (D) interrupt return instruction4. The signal that does not work when accessing external memory is ()(A) (B) (A) (A) ALE5, the following instructions, read only the instructions of the pin is ()(A) MOV P1, A (B) ORL P1, #0FH (C) MOVC C, P1.5 (D) DJNZ P1

8、, LAB6, the use of timer T1, there are several modes of work ()(A) 1 species (B), 2 species (C), 3 species (D), 4 species7, if MCS-51 interrupt sources are programmed as the same level, when they simultaneously apply interrupts, CPU first responds ()(A) (B) (C) T1 (D) T08, when the MCS-51 response i

9、s interrupted, which of the following conditions is not necessary?The current instruction is executed. B, interrupt is open C, no peer or advanced interrupt service D, and must have RETI instruction9, if the 8255 port A is set to mode 2, the port B is set to ()(A) can only be 0 (B) or 2 (C) except f

10、or mode 2, and any other way can (D) any way10, when the MCS-51 multi machine communication, serial interface mode should be ()(A) mode 0 (B) mode 1 (C) mode 2 (D) mode 0 or mode 2Four. Read or write programs (15 points)1. Write a program to transfer the data from the 100 units of the 1000H unit to

11、the beginning of the 2000H. (8 points)2. Set R0=20H, R1=25H, (20H) =80H, (21H) =90H, (22H) =A0H, (25H) =A0H, (26H) =6FH, (27H). After the following program is executed, what is the result?(20H) = (21H) = (22H) = (23H) = CY=R0 = R1 =CLR CMOV R2，# 3环：MOV A，R0ADDC A， R1MOV R0，一INC R0公司R1djnz R2，环JNC下MO

12、V R0，# 01h否则，下一步：DEC R0否则，五、MCS-51单片机外扩展一片2716存储器，画出系统电路原理图，写出地址分布。（15分）六、MCS-51单片机P1端口上，经驱动器接有只发光二极管fosc = 8，6mhz，试编写程序，使这8只发光管每隔2秒循环发光。（20分）单片微机原理及应用一卷参考答案一、填空题（每空1分，共20分）1、I / O 2、低8 3 4 1 5位地址、寄存器间接、2003h，37b0 6、5个，IP 7、符号指令和伪指令8、PC或DPTR 9、电平和脉冲10、方式0.11、输出输入12、读引脚和读锁存器13、转换速度、分辨率和转换精度。二、选择题（从备选

13、答案中选择一个正确答案，并将代号写在括号内。每题1。分，共10分）1，C 2，B 3，D 4，C 5，C 6，C 7，B 8，C 9，A 10，C三、简答题（每题5分，共20分）1、MCS-51单片机内部包括哪些主要逻辑功能部件？答：MCS-51单片机主要由下列部件组成：1个8位CPU；1个片内振荡器及时钟电路；4kb ROM程序存储器，256bram；21个特殊功能寄存器；2个16位定时/计数器；4个8位并行I/O口及1个可编程全双工串行接口；可寻址64kb的外部程序存储器空间；可寻址64kb的外部数据存储器空间；5个中断源、两个优先级中断嵌套中断结构。2、MCS-51单片机内部有几个定时/

14、计数器？它们由哪些寄存器组成？答：MCS-51单片机内部有两个16位可编程的定时/计数器，简称定时器0（T0）和定时器1（T1）。它们分别由方式寄存器TMOD、控制寄存器TCON和数据寄存器Th0、TL0，Th1、TL1组成。3、单片机对中断优先级的处理原则是什么？答：（1）低优先级中断源可被高优先级中断源所中断，而高优先级中断源不能被任何中断源所中断；（2）一种中断源（不管是高优先级还是低优先级）一旦得到响应，与它同级的中断源不能再中断它。当同时收到几个同一优先级的中断时，响应哪一个中断源取决于内部查询顺序。其优先级排列如下：中断源同级内的中断优先级0最高外部中断定时器/计数器0溢出中断外部

15、中断1定时器/计数器1溢出中断串行口中断最低4、设MCS-51单片机的Fosc12MHz，要求用T0定时150us，分别采用定时方式0，定时方式1和方式2时的定时初值。采用方式0定时的初值为FBH，50h采用方式1定时的初值为FFH，6ah采用方式2定时的初值为6ah四、阅读或编写程序1、编写一程序实现将1000h单元开始的100个单元的数据转移到2000h开始的单元中。（8分）程序如下：ORG 0000HMOV DPTR，# 1000h；给源数据块地址指针DPTR赋初值MOV P2，# 20h；给目的数据块地址指针P2和R0赋初值MOV R0，# 00h环：MOVX指令，指令MOVX R0，一INC DPTRINC R0cjne R0，# 64h，环否则，2、设R0 = 20h，R1 25h (20h) = = = = = 90h 80h, (21h), (22h) = (a0h, 25h) = (a0h, 26h) = (6fh, 27h), after the following program is executed, what is the result (7 points)?(20h) = (= 21h (20h) 00h 22h) = (23h 17h 01h CY A = 1) = = = 28h 17h R0 23h R1CL