51单片机中断优先级基本原则
51单片机中断知识总结
51单片机中断知识总结如下：一、中断概念中断是一种特殊的事件处理机制，当单片机在执行程序时，如果发生某种突发事件（如外部中断请求、定时器溢出等），需要立即处理，这时单片机就会暂时中断当前的工作，转去处理这个突发事件。
处理完后再回到原来被中断的地方继续执行程序。
这个过程就称为中断。
二、51单片机的中断系统结构51单片机的中断系统由中断允许寄存器IE控制。
IE寄存器可以控制所有中断以及某个中断源的开放和屏蔽。
三、中断标志位中断标志位是用于标识某个事件是否发生的中断信号。
当发生某个事件时，硬件会自动置位相应的中断标志位。
四、中断响应条件中断响应条件包括两个：1）允许中断标志位为1；2）相应中断的优先级最高。
只有当这两个条件都满足时，单片机才会响应中断。
五、中断处理中断处理是对中断源进行有针对性的服务。
用户需要编写相应的中断处理程序，以便在发生中断时执行相应的操作。
六、中断返回中断返回是指返回到主程序断点处，继续执行主程序。
这个过程由硬件自动完成。
七、外部中断外部中断是由外部设备产生的中断请求。
在51单片机中，外部中断可以通过INT0和INT1引脚输入。
外部中断的触发方式可以是下降沿触发或电平触发。
八、定时器中断定时器中断是由定时器溢出产生的中断请求。
当定时器溢出时，硬件会自动置位相应的中断请求标记，并产生中断请求。
九、串口中断串口中断是由串行口接收完一帧数据后产生的中断请求。
当串行口接收完一帧数据后，硬件会自动置位相应的中断请求标记，并产生中断请求。
以上就是关于51单片机中断的知识总结，希望能够帮助到您。
各中断源的中断优先级关系的两条基本规则
各中断源的中断优先级关系的两条基本规则
各中断源的中断优先级关系的两条基本规则如下：
1. 低优先级可被高优先级中断，高优先级不能被低优先级中断。
2. 任何一种中断（不管是高级还是低级）一旦得到响应，不会再被它的同级中断源所中断。
这两条规则决定了在多个中断同时发生时，CPU将如何处理这些中断。
具
体来说，CPU会首先处理优先级高的中断，待处理完毕后再处理优先级较
低的中断。
此外，一旦某个中断正在被处理，同级的其他中断将不会被响应。
以上信息仅供参考，如需了解更多信息，建议查阅计算机原理或操作系统相关书籍。
(最新整理)51单片机复习要点
定时/计数器1低字节 TH0 8CH
定时/计数器1高字节 TH1 8DH
P1口
P1
90H
97
96 95 94
93
92 91 90
电源控制
PCON 87H SMOD
GF1 GF0 PD IDL
串行口控制
SCON 98H
SM0 SM1 SM2 REN TB8 RB8 TI RI
9F
9E 9D 9C 9B 9A 99 98
9
片内RAM的低128字节单元
分为三个区域：
①寄存器区（ 00H～1FH ）
4组寄存器区，0组～3组。每组8个寄
存单元（每单元8位），以R0～R7作寄存
单元名，用于暂存运算数据和中间结果。
字
节
用PSW中的两位PSW.4和PSW.3来选择其中一
地
组寄存器区。
址
位地址
② 位寻址区 （ 20H～2FH）
(最新整理)51单片机复习要点
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8051的主要硬件资源有：
◆8位CPU； ◆片内带振荡器，频率范围为1.2~12MHz； ◆256字节片内数据存储器RAM； ◆4KB片内程序存储器ROM； ◆程序存储器的寻址范围为64KB； ◆片外数据存储器RAM的寻址范围64KB； ◆4个8位的并行I/O接口：P0、P1、P2、P3； ◆1个全双工的串行I/O接口，可多机通信； ◆2个16位定时器/计数器：T0、T1； ◆5个中断源。
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MCS-51单片机的引脚及功能
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40个引脚可分为4部分：
2个主电源引脚 2个外接晶体引脚 4个控制引脚 32个I/O引脚
51单片机中断控制
计数个数与计数初值的关系为： X=216 -N
三、方式2 方式2为自动重装初值的8位计数方式。
TCON TF1 申请 中断 TR1 TF0 TR0 TH0 8位 D0 D7 溢出 1 TL0 &
≥1
TMOD T0引脚 0 1 M0 M1 C/T 0 机器周期 GATE M0 1 INT0引脚 M1 C/T GATE D7 D0
同一优先级中的中断申请不止一个时，则有中 断优先权排队问题。同一优先级的中断优先权排队， 由中断系统硬件确定的自然优先级形成，其排列如 所示：
设置52单片机的4个中断源,使他们的优顺序 为T1,INT1,INT0,T0.
IPH = 0X08; IP = 0X40; PT1 = 1; PX1 = 1;
≥1
TMOD T0引脚 1 1 0 0 0 M0 M1 C/T 机器周期 GATE M0 1 D0 INT0引脚 M1 C/T GATE D7 D0
定时器模式时有:N＝t/ Tcy 计数初值计算的公式为： X=213 -N
定时器的初值还可以采用计数个数直接取补法获得。
计数模式时，计数脉冲是T0引脚上的外部脉冲。
设置为定时器模式时，加1计数器是对内部机器周期 计数（1个机器周期等于12个振荡周期，即计数频率 为晶振频率的1/12）。计数值N乘以机器周期Tcy就 是定时时间t 。 设置为计数器模式时，外部事件计数脉冲由T0或T1 引脚输入到计数器。在每个机器周期的S5P2期间采 样T0、T1引脚电平。当某周期采样到一高电平输入， 而下一周期又采样到一低电平时，则计数器加1，更 新的计数值在下一个机器周期的S3P1期间装入计数 器。由于检测一个从1到0的下降沿需要2个机器周期， 因此要求被采样的电平至少要维持一个机器周期。当 晶振频率为12MHz时，最高计数频率不超过1/2MHz， 即计数脉冲的周期要大于2 s。
51单片机中断控制
51单片机中断控制在单片机的世界里，中断控制就像是一位高效的调度员，能够让单片机在处理各种任务时更加灵活和高效。
今天，咱们就来好好聊聊 51 单片机的中断控制。
咱们先来了解一下啥是中断。
简单说，中断就是在单片机正常执行主程序的时候，突然有个更紧急或者更重要的事情需要处理，这时候单片机就会暂停主程序，先去处理这个紧急的事情，处理完了再回来继续执行主程序。
51 单片机有 5 个中断源，分别是外部中断 0 和 1、定时器/计数器 0 和 1 的溢出中断，还有串行口中断。
每个中断源都有自己的中断标志位和中断允许位。
外部中断 0 和 1 可以通过单片机的引脚来触发。
比如说，当外部引脚检测到一个下降沿或者低电平时，就可以产生中断。
这在很多实际应用中非常有用，比如检测按键按下、外部设备的信号变化等。
定时器/计数器 0 和 1 的溢出中断则是当定时器或者计数器的值达到设定的最大值时产生中断。
这就好比一个闹钟，设定好时间，时间一到就响铃提醒单片机去做相应的处理。
串行口中断则是在串行通信过程中，当发送或者接收完一帧数据时产生中断，方便单片机及时进行数据处理。
要让中断能够正常工作，还得设置好相关的寄存器。
中断允许寄存器 IE 用来控制各个中断源是否允许中断。
比如说，如果要允许外部中断 0 中断，就需要把 IE 寄存器中的相应位设置为 1。
中断优先级寄存器 IP 则用来确定各个中断源的优先级。
当多个中断同时发生时，优先级高的中断会先得到处理。
在编写中断服务程序的时候，有几个要点需要注意。
首先，中断服务程序要有一个特定的函数格式，一般是以“void 中断服务函数名(）interrupt 中断号”这样的形式来定义。
然后，在中断服务程序中，要尽量快速地完成关键处理，因为中断服务程序会打断主程序的执行，如果处理时间过长，可能会影响主程序的实时性。
比如说，在一个温度控制系统中，主程序负责采集温度数据、显示温度等常规操作。
而外部中断0 可以用来检测温度超过设定的上限值，一旦触发中断，中断服务程序就会迅速采取降温措施，比如启动风扇或者关闭加热设备，然后迅速返回主程序。
简述中断优先级的处理原则
简述中断优先级的处理原则
中断优先级的处理原则是指当多个中断源同时发生，系统按照它们的
优先级来处理。
优先级越高，代表事件处理的优先程度越高，处理的越早，在多个中断源发生时，系统会先处理高优先级中断，而忽略低优先级中断。
一般而言，每个中断源都拥有自身的中断优先级，可以通过设置来调整，典型的中断优先级可以分为“最高”，“高”，“中”，“低”，
“最低”等几个等级，可以根据处理中断源的实时应用需求调整中断优先级。
在中断处理过程中，如果优先级较高的中断发生时，系统将会忽略低
优先级的中断，但是当所有优先级比较高的中断处理完毕后，系统还会处
理低优先级的中断，这样可以确保系统按照中断优先级的顺序处理中断，
防止高优先级的中断被低优先级的中断延缓。
51单片机中断(51singlechipinterrupt)
51单片机中断（51 singlechip interrupt）51单片机中断(51 singlechip interrupt)Say the most basic, the old 51 single chip microcomputer (80C51 Series) has 5 interrupt source, 2 priority, can achieve two levels of interrupt service nesting. Many expanded 51 microcontrollers now have 4 priority levels (or more) and more interrupt sources.Before talking about interruption, I first define the priority, understand what the priority is, and the later statement is easy to understand. In fact, many people are confused about the priority of meaning, so that in disorderly fashion.There are two priority levels for the interrupt: query priority and execution priority.What is the optimal query? The default we see from the datasheet or the book (the IP register is not set, the power on reset is 00H) priority: external interrupt 0 > timer / counter 0 > external interrupt 1 > timer / counter 1 > serial interruptOr INT0, timer0, INT1, Timer1, serial, port or INT0, T0, INT1, T1, UART, or PX0>PT0>PX1>PT1>PS>......Is the query quality. First, the query priority cannot be changed and set. This is a problem of queuing priority with interruption. When multiple interrupt sources interrupt the signal at the same time, the interrupt arbiter selects the order in which interrupt source priority should be processed. This does not have anything to do with theinterruption of the nesting of service programs. When the CPU query interrupt flag all the time, will be in accordance with the above 5 querypriority order query, when the number of interrupt requests at the same time, will give priority to the high quality query query first level interrupt flag, but does not represent a high priority interrupt query can interrupt the already low priority and executing the query interrupt service.For example: when the counter 0 interrupt and 1 (according to the query priority, counter 0 external interrupt interrupt > 1) when they arrive at the same time, will enter the timer 0 interrupt service function; but in the external interrupt interrupt service function 1 is service, then any interruptions are not to interrupt it, including external logic it is higher priority than interrupt 0 interrupt counter 0.The priority of the interrupt is the setting of your IP register. In the case of 2 priority, a bit is 1, then the corresponding interrupt source is of high priority; 0 is a low priority.There are three principles for the priority of interrupts:1 and CPU receive several interrupts at the same time, first responding to the highest priority interrupt request;2, the ongoing interrupt process cannot be interrupted by a newlevel or low level interrupt request;3, the ongoing low level, first class interrupt service, can be interrupted by the higher level of the first interrupt;If there is more than one interrupt application in the sameexecution priority, there is an interrupt priority queuing problem. Interrupt priority queue with an execution priorityinterrupt priority, formed by the natural system hardware to determine the priority from high to low order: 0> external interrupt timer / counter 0> 1> external interrupt timer / counter serial interface 1> For example: set IP = 0x10, which is set as the highest priority is the serial port, serial port interrupt can interrupt any other interrupt service function nested, and only can interrupt other serial interrupt interrupt service function. If the serial interrupt is not triggered, the other interrupts remain logical priority and cannot be nested with each other.About interrupt nesting. It can be said that when an interrupt is executed, if set interrupt priority register IP, so when a higherpriority interrupt arrival will interrupt nesting, if not set, therewill not be any nested; if the same interrupt priority level trigger, it is not in "application", but it will be the corresponding interrupt flag register IE position is a position, when the CPU executes the current interrupt, according to each query query priority interrupt flag, enter the corresponding interrupt.Remember that when you do not set up the IP, the microcontrollerwill queue up to enter the service in terms of query priority (orlogical priority). If you want a priority response from an interrupt,set IP and change the priority level (or physical priority). Note that when the IP is set, when the low execution priority interrupt is running, if there is a high execution priority interrupt, nested interrupts are called into the high execution priority. If you are a program written in C, and whenyou break the service, the using has the storage group. Be awarethat two interrupt service programs with different execution priorities do not using the same set of registers.Look at the following two questions:1 when each interrupt is low priority, if the overflow of timer 0 goes into interrupt. In this interrupt process, the external interrupt 0 is also triggered, so is the interrupt nesting necessary?2 if the timer 0 breaks, enter the interrupt handler,At this time, 1 conditions were interrupted and the condition was satisfied. Because the timer 0 has a natural priority higher than the external interrupt 1, then the interrupt handler for timer 0 continuesto execute. Assuming that the timer interrupt handler executes the process, the external interrupt 1 is triggered. If the condition is gone, then when the timer 0 is interrupted, will the program go into the external interrupt 1 program?Answer 1: in the IP prior to setting the external interrupt 0priority, CUP will interrupt the timer 0 interrupt service, access tothe external interrupt 0 service program, after the execution, then go back to timer 0 interrupt service program. Otherwise.Answer: 2 will enter the interrupt; external interrupt 1 trigger condition will set external interrupt flag 1, even though the external interrupt trigger condition 1 disappeared,also not clear the interrupt flag has been set, so the timer 0 interrupt processing after the procedures for contracting external interrupt interrupt flag off the 1 still will enter the 1 external interrupt handling procedures, only when the external interruptexecution instructions will remove reti hardware interrupt flag 1 1 external interrupt handler (which is why interrupt return using the reti instruction and can not be replaced by ret.)...The internal MCS -51 microcontroller has a full duplex serial port, serial send and receive buffer (SBUF), the two physically separate receiver transmitter, which can receive data can also send data. However, the receive buffer can only be read out and cannot be written, while the transmit buffer can only be written and cannot be read out. Their address is 99H. The communication port can be used for network communication, serial asynchronous communication and synchronous shift register. If a level converter is added to the input and output pins of the line, it is easy to form a standard RS-232 interface. Here are some of them.[1]. basic conceptsThe mode of transmission of data communicationThe transmission mode is often used for data communication are simplex, half duplex and full duplex and multiplex method.Simplex mode: data only in a fixed direction. Therefore, this modeof transmission is limited in use. It is used for data transmission between serial ports and data acquisition betweensimple systems.Half duplex mode: data can be transmitted in two directions, but not at the same time. The actual application uses some protocol to realize the switch of receive / output.Full duplex mode: both sides are allowed to perform two-way data transmission at the same time, but the circuit and equipment in general full duplex transmission are more complicated.Multi way: more than three kinds of transmission is a transmission frequency signal with the same line, in order to make full use of the line resources, by using a multiplexer or multiplexer hub, using frequency division and time-division and code division multiplexing technology can be realized on the same line of resource sharing, wefilled the multiplex transmission.There are two forms of serial data communicationAsynchronous communication: in this communication, the receiver and the transmitter has its own clock, their work is not synchronous, asynchronous communication with a frame to represent a character, its contents are as follows: a start bit, only then is the number of bits of data, figure 2 is the transmission of 45H data format.Synchronous communication: synchronous communication format, transmitter and receiver clock source controlled by the same time, in order to overcome in asynchronous communication, each transmission frame character must be coupled with start andstop bits, occupy the transmission time in a large amount of data transmission requirements of occasions, speed is much slower. The synchronous transfer mode removes these start bits and stop bits and sends only a synchronous header (character) flag only when the data block is transmitted.Synchronous transmission is faster than asynchronous transmission, which is its advantage. But synchronous transmission has its drawback, that is, it must use a clock to coordinate the work of transceiver, so its equipment is also more complex.2008-3-10 upload and download attachments at 10:13 (10.44, KB)Transmission rate of serial data communicationThere are two concepts of serial data transmission rate, i.e. the number of BPS per second transfer (Bit per second) and the number of symbols per second - baud rate (Band rate), in communication with the modem, the baud rate associated with the modulation rate.[2]. MCS-51 serial port and control registerSerial port control registerThe serial port register structure of MCS -51 single chip microcomputer is shown in figure 3. SBUF is the transceiver buffer of serial port. It is an addressable special register, which contains thereceiver and transmitter register, so that full duplex communication can be realized. But the tworegisters have the same address (99H). MCS-51's serial data transfer is simple, and you can send data as long as you write data to the send buffer.Data is received from the receive buffer to receive data.2008-3-10 upload and download attachments at 10:13 (8.4, KB)In addition, as can be seen from the figure, before receiving buffer plus an input shift register, MCS-51 is the structure of receiving data to avoid data frame overlap, to avoid mistakes, some literature called the structure of double buffer structure. This is not necessary when sending data, because CPU is active when sending, and this phenomenon is not possible.Serial communication control registerIn the previous section, we have analyzed the SCON control register, which is an addressable dedicated register for serial data communication control. The cell address is 98H, and its structure is as follows: Table 1 SCON register structureSCOND7D6D5D4D3D2D1D0SM0SM1SM2RENTB8RB8TIRIBit address9FH9EH8DH9CH9BH9AH99H98HBelow we introduce the function of each control bit as follows: (1).SM0 and SM1: serial port, operation mode, control bit.SM0, SM1 mode of operation00 way 001 way 110 way 211 way 31) mode 0When set to SM1, SM0 is 00, the serial port work in 0 ways, in0, RXD for data input / output, TXD synchronization pulse output, sending or receiving data is 8 bits, low in front, high in the way, the baud rate of 0 /12, which is fixed? Each machine cycle a data transmission. Mode 0 can be externally connected with a shift register, extending the serial port to a parallel port, or an external synchronous input / output device.2) mode 1When setting SM1 and SM0 to 01, the serial port works 1. 1 to 8 baud rate variable asynchronous communication mode, receiving sent by TXD RXD, a frame of data is 10 bits, 1 start bit (low), 8 data bits (LSB first) and 1 stop bit (Gao Dianping), the baud rate depends on the T timer overflow rate (1/ overflow cycle the choice of SMOD and baud rate).Baud rate = * (timer T overflow rate)3) mode 2 and mode 3When SM0 and SM1 are set to 10 or 11, the serial port operates in mode 2 or mode 3, and the two methods are 9 bit asynchronous communication, only baud rate is different, and is suitable for multi machine communication. In 2 or 3, receive data sent by TXD RXD, the 1 frame data is 11 bits, 1 start bit (low), 8 data bits (LSB first), 1 bitprogrammable bits (Ninth bits of data, used for parity or address / data selection), 1 stop a (Gao Dianping). Compared with the method 1, thereis more than one programmable bit. When transmitting, the ninth bit data is TB8, and the ninth bit data is sent into the RB8 when received.Mode (2) baud rate = *Mode (3) baud rate = * (timer T overflow rate)(2).SM2: multi computer communication control bit.Multi machine communication is operated in the manner 2 and mode 3, and the SM2 bit is mainly used in the mode 2 and mode 3. The receiving state, when the serial port in mode 2 or 3, and SM2=1, only when receiving ninth bits of data (RB8) is 1, only to receive the first 8bits of data into SBUF, and set a RI interrupt application, otherwisethe data received will be given up. When SM2=0, regardless of the first bit of data is 0 or 1, it is difficult to send data to SBUF, and sendout an interrupt request.When working at 0, the SM2 must be 0.(3).REN: allow receive bit.REN is used to control the acceptance and prohibition of data reception, and when REN=1 is allowed, the REN=0 is forbidden to receive.(4).TB8: send receive data bit 8.In mode 2 and mode 3, the TB8 is to be sent - the ninth bit databits. In multi machine communication, this bit is also transmitted, andit represents the address or data of transmission, TB8=0 is data, andTB8=1 is address.(5).RB8: receive data bit 8.In mode 2 and mode 3, the RB8 stores the received ninth bit data to identify the received data characteristics.(6).TI: send interrupt flag bit.Addressable flag bit. Mode 0, after sending eighth bits of data, the hardware settings, in other ways, in the transmission or stop bit before the hardware settings, so TI=1 indicates the end of frame transmission, TI can be cleared by software 0".(7).RI: receive interrupt flag bit.Addressable flag bit. After receiving eighth bits of data, the bitis set by the hardware, in other ways, the bit is set by the hardware, and the RI=1 indicates the completion of the frame reception.Power management register PCONPCON is mainly for the CHMOS microcontroller power control set of dedicated registers, the unit address is 87H, its structure is as follows:Table 2 PCON power management register structurePCOND7D6D5D4D3D2D1D0Bit symbolSMOD---GF1GF0PDIDLInterrupt enable register IEThe interrupt permission register has been described in the previous section, where the bits ES that affect the serial port are restated. The ES allows control bits for serial interrupts, and the ES=1 allows serial interrupts, ES=0, and serial interrupts are prohibited.Table 3 IE interrupt enable control register structureBit symbolEA--ESET1EX1ET0EX0Bit address AFHAEHADHACHABHAAHA9HA8H。
单片机中断系统
单⽚机中断系统中断系统的概念和基本结构中断发⽣：CPU正在处理某⼀程序时，发⽣了另⼀突发事件请求CPU迅速去处理；中断响应： CPU暂时停⽌当前的⼯作，转到需要处理的中断源的服务程序的⼊⼝，⼀般在⼊⼝处执⾏⼀跳转指令转去处理中断事件(中断服务)；中断返回：待CPU将中断事件处理完毕后，再回到原来程序被中断的地⽅继续处理执⾏程序，这⼀处理过程称为中断返回。
当CPU与外设交换信息时，由于外设的速度⽐较慢，若⽤查询的⽅式，则CPU就要浪费很多时间去等待外设。
这样就存在⼀个快速的CPU与慢速的外设之间的⽭盾。
为了解决这个问题，就引⼊了“中断”的概念中断的优点分时操作有了中断功能，就可以使CPU和多个外设同时⼯作。
提⾼了CPU的利⽤率。
实时处理实时控制时，需要现场的各种参数、信息，可在任何时间发出中断申请，CPU就可以马上响应加以处理。
故障处理计算机在运⾏过程中，往往会出现事先预料不到的情况，或出现⼀些故障。
中断源引起中断的原因，或能发出中断申请的来源，称为中断源。
通常中断源有以下⼏种：外部输⼊、输出设备故障源控制对象定时/计数脉冲，当定时/计数器溢出时产⽣中断请求。
对于每种中断事件，要求其能够发出中断请求信号，⽽且要符合CPU响应中断的条件，即要明确属于哪种中断源。
中断源是系统规定的可引起中断的部件或来源。
中断系统的功能实现中断及返回能实现优先权排队⾼级中断源能中断低级的中断处理MCS-51单⽚机的中断系统提供5个中断申请源外部中断0和外部中断1；定时/计数器(T0)和(T1)的溢出中断；串⾏接⼝的接收和发送中断。
这5个中断源可分为两个优先级，可实现两级中断服务程序嵌套。
MCS-51单⽚机的中断系统可以提供5个中断申请源，它们的控制与实现由⽚内4个SFR来完成。
定时/计数器的控制寄存器(TCON)和串⾏接⼝控制寄存器(SCON)的相应位规定中断类型和触发⽅式；中断允许寄存器(IE)控制CPU是否响应中断请求；中断优先级寄存器(IP)安排各中断源的优先级，同⼀优先级内各中断同时提出中断请求时，由内部的查询逻辑按规定的⾃然优先级确定其响应次序。
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51单片机中断优先级基本原则
中断是指在程序执行的过程中，由硬件或软件触发，跳转至另一个函数或子程
序中执行一段代码，然后再返回原来的程序执行点。
中断可以提高系统的响应速度和效率，并且可以优先处理紧急事件。
在51单片机的编程中，正确设置中断优先
级是一项重要的任务，本文将介绍51单片机中断优先级的基本原则。
1. 中断的分类
51单片机中的中断主要分为外部中断和定时器中断两种。
外部中断是通过外部引脚触发的，例如按键、传感器等外部事件。
而定时器中断是由定时器计算得出的，用于定时触发一些任务。
2. 中断优先级的概念
在51单片机中，有多个中断源时，中断优先级决定了哪个中断先被执行。
较
高优先级的中断会打断正在执行的较低优先级中断，这样可以保证紧急任务的及时处理。
3. 默认的中断优先级
在51单片机中，默认情况下，各个中断的优先级是相同的。
如果不进行设置，那么多个中断发生时会按照它们的优先级设置顺序进行处理。
4. 中断优先级的设置方法
在51单片机的编程中，可以通过设置中断优先级来控制各个中断的执行顺序。
下面是一种设置中断优先级的方法：
a. 在程序中开启中断：通过设置中断打开寄存器（IE）的对应位来开启相应
的中断源。
b. 设置中断优先级：通过设置中断控制寄存器（IP）的对应位来设置中断的
优先级。
IP寄存器的每一位对应一种中断源，可以根据需要设置为高优先级或低
优先级。
5. 中断优先级的基本原则
在设置中断优先级时，需要遵守一些基本的原则：
a. 优先处理时间敏感的中断：对于需要立即响应的事件，例如紧急报警、高
优先级的通信等，应该将其设置为较高的中断优先级。
这样可以保证紧急任务的及时处理。
b. 避免高优先级中断长时间持续运行：较高优先级的中断可能会一直打断低
优先级的中断，导致低优先级的任务得不到处理。
因此，需要合理设置中断优先级，避免高优先级中断长时间占用CPU资源。
c. 合理规划定时器中断和外部中断的优先级：定时器中断一般用于周期性任务，例如控制任务的周期性执行。
而外部中断一般用于处理紧急事件。
在设置这两种中断的优先级时，需要根据具体应用场景进行合理规划。
d. 细分中断优先级：有时候，多种中断源需要按照不同的优先级进行处理。
可以通过使用多级中断优先级（如高中低三个级别）或者使用软件实现优先级的细分。
6. 中断优先级的调试和验证
在编写程序时，设置中断优先级后需要进行调试和验证。
可以通过模拟测试，
在特定的条件下触发多个中断，观察程序的执行顺序和中断的响应情况，以确保中断优先级的设置符合设计要求。
总结：
本文介绍了51单片机中断优先级的基本原则。
正确设置中断优先级可以提高
系统的响应速度和效率，能够优先处理紧急事件。
在设置中断优先级时，需要考虑时间敏感性、避免长时间占用CPU资源、合理规划不同类型中断的优先级等因素。
调试和验证是确保中断优先级设置正确的重要步骤。
只有正确设置中断优先级，才能充分发挥51单片机的中断机制，提高系统的稳定性和可靠性。