Copied directly from the Internet. I don’t know if you can use it.

How does IP realize network interconnection? Network systems and equipment produced by various manufacturers, such as Ethernet, packet switching network, etc., cannot interoperate with each other. The main reason why they cannot interoperate is because of the basic unit of data they transmit (technically called "frame"). The format is different. The IP protocol is actually a set of protocol software composed of software programs. It uniformly converts various "frames" into "IP data packet" format. This conversion is one of the most important features of the Internet, enabling all kinds of computers to All can achieve interoperability on the Internet, that is, they have the characteristics of "openness". So, what is a "packet"? What are its characteristics? Data packets are also a form of packet switching, which means to segment the transmitted data into "packets" and then transmit them out. However, unlike traditional "connection-type" packet switching, it is "connectionless". Each "packet" (group) is sent out as an "independent message", so it is called "data". Bag". In this way, there is no need to connect a circuit before starting communication, and each data packet is not necessarily transmitted through the same path, so it is called "connectionless". This feature is very important as it greatly improves the robustness and security of the network. Each data packet has two parts: header and message. The header contains necessary content such as the destination address, so that each data packet can accurately reach the destination without going through the same path. Reassemble and restore the original sent data at the destination. This requires IP to have the functions of packet packaging and collection assembly. During the actual transmission process, the length of the data packet must also be changed according to the packet size specified by the network it passes through. The maximum length of the IP data packet can reach 65535 bytes. There is also a very important content in the IP protocol, which is that every computer and other device on the Internet is assigned a unique address, called an "IP address." Because of this unique address, it is ensured that users can efficiently and conveniently select the objects they need from thousands of computers when operating on connected computers. Now the telecommunications network is integrating with the IP network. New technologies based on IP are popular technologies. For example, the technology of using IP network to transmit voice (ie VoIP) is very popular. Others such as IP over ATM, IP over SDH, IP over WDM Etc., are all the focus of research on IP technology.

[Edit this paragraph]IPV4 address

The so-called IP address is a 32-bit address assigned to each host connected to the Internet. According to the TCP/IP (Transport Control Protocol/Internet Protocol) protocol, IP addresses are represented in binary. Each IP address is 32 bits long. When bits are converted into bytes, they are 4 bytes. For example, an IP address in binary form is "00001010000000000000000000000001". It is too laborious for people to process such a long address. In order to facilitate people's use, IP addresses are often written in decimal form, with the symbol "." in the middle to separate different bytes. Therefore, the above IP address can be expressed as "10.0.0.1". This representation of IP addresses is called "dotted decimal notation", which is obviously much easier to remember than 1 and 0. Some people may think that a computer can only have one IP address. This view is wrong. We can specify a computer to have multiple IP addresses, so when accessing the Internet, do not think that one IP address is one computer; in addition, through specific technologies, multiple servers can also use one IP address. The server looks like a host to the user. By dividing the IP address into two parts, the network number and the host number, the designer must decide how many bits each part contains.

The number of digits in the network number directly determines the number of networks that can be allocated (calculation method 2^number of digits in the network number); the number of digits in the host number determines the maximum number of hosts in the network (calculation method 2^number of digits in the host number-2) . However, since the network size contained in the entire Internet may be relatively large or relatively small, the designers finally cleverly chose a flexible solution: dividing the IP address space into different categories, each category has a different network number digits and host number digits. The IP address is the basis for data transmission in the IP network. It identifies a connection in the IP network. A host can have multiple IP addresses. The IP address in the IP packet remains unchanged during network transmission. (1) Basic address format (IPv4) Current IP networks use 32-bit addresses, expressed in dotted decimal notation, such as 192.168.0.1. The address format is: IP address = network address + host address or IP address = network address + subnet address + host address. Network addresses are assigned by ICANN (the Internet Corporation for Assigned Names and Numbers) of the Internet Society, which includes InterNIC responsible for North America, RIPENIC responsible for Europe, and APNIC responsible for the Asia-Pacific region. The purpose is to ensure the global uniqueness of network addresses. Host addresses are assigned by the system administrator of each network. Therefore, the uniqueness of the network address and the uniqueness of the host address within the network ensure the global uniqueness of the IP address. (2) Allocation of reserved addresses Depending on the purpose and security level, IP addresses can be roughly divided into two categories: public addresses and private addresses. Public addresses are used on the Internet and can be accessed anywhere on the Internet. Private addresses can only be used within the internal network and can communicate with the Internet only through a proxy server.

IP address query

Start---Run, enter cmd---enter ipconfig/all in the pop-up dialog box, and then press Enter to display a list, one of which is: ip address is the IP address

Classification of IP addresses

Network number: used to identify the network where the host is located; host number: used to identify the host in the network. IP addresses are divided into five categories, Class A is reserved for government agencies, Class B is allocated to medium-sized companies, Class C is allocated to anyone who needs it, Class D is used for multicast, Class E is used for experiments, and various types can accommodate The number of addresses is different. Characteristics of the three types of IP addresses A, B, and C: When the IP address is written in binary form, the first digit of the Class A address is always 0, the first two digits of the Class B address are always 10, and the first three digits of the Class C address are always 0. Always 110. 1. Class A address (1) The first byte of the Class A address is the network address, and the other 3 bytes are the host address. (2) Class A address range: 1.0.0.1---126.255.255.254 (3) Private addresses and reserved addresses in Class A addresses: ① 10.X.X.X is a private address (the so-called private address is not used on the Internet, and are used in local area networks). Range (10.0.0.0---10.255.255.255) ② 127.X.X.X is a reserved address and is used for loop testing. 2. Class B address (1) The first and second bytes of the Class B address are the network address, and the other two bytes are the host address. (2) Class B address range: 128.0.0.1---191.255.255.254. (3) Private addresses and reserved addresses of Class B addresses ① 172.16.0.0---172.31.255.255 is a private address ② 169.254.X.X is a reserved address. If your IP address is obtained automatically and you do not find an available DHCP server on the network. You will get one of the IPs.

3. Class C address (1) The 1st, 2nd and 3rd bytes of the Class C address are the network address, and the 4th byte is the host address. In addition, the first three digits of the first byte are fixed to 110. (2) Class C address range: 192.0.0.1---223.255.255.254. (3) Private address in Class C address: 192.168.X.X is a private address. (192.168.0.0---192.168.255.255) 4. Class D address (1) Class D address does not distinguish between network address and host address. The first four digits of its first byte are fixed to 1110. (2) Class D address range: 224.0.0.1---239.255.255.254 5. Class E address (1) Class E address does not distinguish between network address and host address. The first five digits of its first byte are fixed to 11110 . (2) Class E address range: 240.0.0.1---255.255.255.254 The concept of IP is very broad, including brand, trademark, copyright, and very importantly, business secrets, business models, business standards, etc. The amount of IP owned is the most important indicator that distinguishes manufacturing from creation. If a country owns too little IP, its industries or enterprises can only play the role of primary processors in the international division of labor.

Special IP addresses

In the IP address space, some IP addresses cannot be assigned to devices, some IP addresses cannot be used on the public network, and some IP addresses can only There are many special IP addresses used on this machine: Multicast address, pay attention to the difference between it and broadcast. This is the address from 224.0.0.0 to 239.255.255.255. 224.0.0.1 refers specifically to all hosts, and 224.0.0.2 refers specifically to all routers. Such addresses are mostly used for some specific programs and multimedia programs. If your host has the IRDP (Internet Route Discovery Protocol, using multicast function) function enabled, then there should be such a route in your host's routing table. 169.254.x.x If your host uses the DHCP function to automatically obtain an IP address, then when your DHCP server fails, or the response time is too long and exceeds a system-specified time, the Windows system will assign such an address to you. If you find that your host IP address is an address such as this, unfortunately, your network is probably not functioning properly. Restricted Broadcast Address Broadcast communication is a one-to-all communication method. If the binary numbers of an IP address are all 1, that is, 255.255.255.255, then this address is used to define the entire Internet. If the device wants the IP datagram to be received by the entire Internet, it sends a broadcast packet with a destination address of all 1, but this will bring a catastrophic burden to the entire Internet. Therefore, all routers on the network prevent packets of this type from being forwarded, limiting such broadcasts to the local network segment. Direct broadcast address The last address in a network is the direct broadcast address, that is, the address whose HostID is all 1. The host uses this address to send an IP datagram to all devices on the local network segment, and the router forwards this datagram to all hosts on the specific network. Note: This address can only be used as the destination address in IP datagrams. In addition, direct broadcast addresses reduce the number of addresses that can be assigned to devices in a network segment by one. The IP address is 0.0.0.0. If the IP address is all 0, that is, 0.0.0.0, then this IP address can only be used as the source IP address in the IP datagram. This happens when the device starts but does not know its own IP. Address case. Such addresses are common in network environments that use DHCP to assign IP addresses.

In order to obtain an available IP address, the user host sends an IP packet to the DHCP server, using such an address as the source address, and the destination address is 255.255.255.255 (because the host does not yet know the IP address of the DHCP server at this time). An IP address with a NetID of 0 can be used when a host sends packets to other hosts on the same network segment, and the packet will not be forwarded by the router. For example, when a host 12.12.12.2/24 in the network 12.12.12.0/24 communicates with another host 12.12.12.8/24 in the same network, the destination address can be 0.0.0.8. Loopback address All addresses in the 127 network segment are called loopback addresses, which are mainly used to test whether the network protocol is working properly. For example, you can use ping 127.1.1.1 to test whether the local TCP/IP protocol has been installed correctly. Another use is when the client process uses the loopback address to send a message to the server process located on the same machine. For example, enter 127.1.2.3 in the browser. This can be used to test whether IIS starts normally when network routing is excluded. . Private addresses In the IP address space, some IP addresses are defined as private addresses. Such addresses cannot be assigned to devices on the Internet network and can only be used within the enterprise, so they are also called private addresses. To use such an address on the Internet, network address translation or port mapping technology must be used. These private addresses are: 10/8 Address range: 10.0.0.0 to 10.255.255.255 *** There are 2 to the power of 24 addresses 172.16/12 Address range: 172.16.0.0 to 172.31.255.255 *** There are 2 of 20 Addresses 192.168/16 Address range: 192.168.0.0 to 192.168.255.255 *** There are 2 addresses. Extended functionality to support authentication, data integrity, and (optional) data confidentiality is specified in IPv6. .

[Edit this paragraph] Development and characteristics of IPV6

IPv6 is the abbreviation of "Internet Protocol Version 6", also known as the next generation Internet protocol. It was developed by the IETF group ( A new IP protocol designed by the Internet Engineering Task Force to replace the current IPv4 (current IP) protocol. We know that all hosts on the Internet have a unique IP address. The IP address uses a 32-bit binary number to represent a host number. However, the 32-bit address resources are limited and cannot meet the needs of users. Therefore, the Internet Research Organization released a new Host identification method, IPv6. In RFC1884 (RFC is the abbreviation of Request for Comments Document. RFC is actually some standards for Internet services), the specified standard syntax recommends writing the 128 bits (16 bytes) of the IPv6 address as eight 16-bit unsigned Integers, each integer is represented by four hexadecimal digits, and these numbers are separated by colons (:), for example: 3ffe:3201:1401:1280:c8ff:fe4d:db39 IPv6 features: Extended addressing capabilities IPv6 Extend the IP address length from 32 bits to 128 bits to support more levels of address hierarchies, more addressable nodes, and simpler address auto-configuration. Improved scalability of multicast routing by adding a "scope" field to the multicast address.

A new address type is also defined, called an "anycast address", for sending packets to any one of a group of nodes; simplified header format Some IPv4 header fields were removed or made optional to reduce packet size Consumption of routine processing during processing and limiting the bandwidth consumed by IPv6 headers; Improved support for extended headers and options. Changes in IP header option encoding can improve forwarding efficiency, make restrictions on option lengths more relaxed, and provide the opportunity to introduce new ones in the future. Greater flexibility in options; The ability to identify flows adds a new ability to identify packets belonging to a specific communication "flow" that the sender requires special handling (such as non-default quality of service or "real-time" service) Become possible; Authentication and encryption capabilities IPv6 specifies extended capabilities to support authentication, data integrity and (optionally) data confidentiality.

[Edit this paragraph] Proxy IP

Proxy IP is a proxy server, and its full English name is Proxy Server. Its function is to act as a proxy for network users to obtain network information. To put it figuratively: it is a transfer station for network information. Under normal circumstances, when we use a web browser to directly connect to other Internet sites to obtain network information, we must send a Request signal to get a reply, and then the other party sends the information back in bit mode. The proxy server is a server between the browser and the Web server. With it, the browser does not go directly to the Web server to retrieve the web page but sends a request to the proxy server. The Request signal will be sent to the proxy server first. The proxy server retrieves the information needed by the browser and sends it to your browser. Moreover, most proxy servers have a buffering function, just like a large Cache, which has a large storage space. It constantly stores newly obtained data in its own memory. If the data requested by the browser If it already exists and is the latest in its local memory, then it will not re-fetch the data from the Web server, but directly transfer the data in the memory to the user's browser, which can significantly improve browsing speed and efficiency. More importantly: Proxy Server (proxy server) is an important security function provided by the Internet link-level gateway. It works mainly in the conversation layer of the Open Systems Interconnection (OSI) model. The main functions are: 1. Break through your own IP access restrictions and access foreign sites. Network users such as Education Network and 169 Network can access foreign websites through proxies. 2. To access internal resources of some units or groups, such as FTP of a certain university (provided that the proxy address is within the allowed access range of the resource), you can use the free proxy server in the address segment of the education network, which is open to the education network. Various FTP downloads and uploads, as well as various data query and other services. 3. Break through China Telecom's IP blockade: China Telecom users have restricted access to many websites. This restriction is artificial, and different Serves block addresses differently. Therefore, if you cannot access it, you can try a foreign proxy server. 4. Improve access speed: Usually proxy servers set up a large hard disk buffer. When external information passes through, it is also saved in the buffer. When other users access the same information again, it is directly accessed by The information is taken out from the buffer and passed to the user to improve access speed. 5. Hide real IP: Internet users can also hide their IP through this method to protect themselves from attacks.

[Edit this paragraph]IP certification

IP certification (Identity Preservation Certification) is a guarantee system established by enterprises to maintain the specific identity of products (such as genetically modified identity). According to specific The process of standard review and certification.

The IP system is to prevent the contamination of potential genetically modified ingredients in food, feed and seed production by strictly controlling the entire production supply chain from the sowing of non-GMO crop seeds to the field management, harvesting, transportation, export and processing of agricultural products. , testing, the establishment of traceability information and other measures to ensure the purity of the "identity" of non-GMO products and improve the production and quality assurance system of product value. The characteristics of the IP system are: (1) Traceability, providing products with comprehensive information on the entire production supply chain (2) Strict isolation to prevent the accidental mixing of all uncontrolled materials (3) Strategic representative sampling and Test and verify the non-GMO identity of products (4) Complete system documents and procedure manuals, the basis for product quality assurance (5) Strict internal and external controls to ensure the effective operation of the IP system. Another: The world's largest paper products and forest products company: International Paper, abbreviated as IP

[Edit this paragraph] Other meanings of IP

1. In electronic products, another meaning of IP is waterproof and dustproof The IP (International Protection) protection level system is drafted by the IEC (International Electro Technical Commission). Lamps are classified according to their characteristics of being dust-proof, preventing the intrusion of foreign objects, being waterproof, and being moisture-proof. Foreign objects referred to here include tools, human fingers, etc. Do not touch the live parts of the lamp to avoid electric shock. The IP protection level is composed of two numbers. The first number indicates the level of dust-proofing and preventing the intrusion of foreign objects; the second number indicates the degree of sealing of the lamp against moisture and waterproof intrusion. The larger the number, the higher the protection level. The protection levels represented by the two marked numbers are as shown in Table 1 and Table 2. The first marked characteristic number (number) refers to the degree of protection. The first marked number: 0 No protection. No special protection for outside people or objects. IP0- 1. Prevent the intrusion of solid objects larger than 50mm and prevent the human body (such as the palm of your hand). Accidental contact with internal parts of the lamp. Prevent the intrusion of large-sized foreign objects (diameter greater than 50mm) IP1- 2 Prevent the intrusion of solid objects greater than 12mm and prevent human fingers from contacting the internal parts of the lamp. Prevent the intrusion of medium-sized foreign objects (diameter greater than 12mm, length greater than 80mm) IP2-3 Prevent the intrusion of solid objects greater than 2.5mm, prevent the intrusion and contact of tools, wires or similar small foreign objects with a diameter or thickness greater than 2.5mm The internal parts of the lamp are IP3-4 to prevent the intrusion of solid objects larger than 1.0mm, and to prevent the intrusion of tools, wires or similar small foreign objects with a diameter or thickness larger than 1.0mm and contact with the internal parts of the lamp. IP4-5 are dustproof and completely protected. Foreign object intrusion.

Although it cannot completely prevent the intrusion of dust, the amount of intruded dust will not affect the normal operation of the lamp. IP5-6 dust tightness completely prevents the intrusion of foreign objects and can completely prevent the intrusion of dust. IP6- The second marked characteristic number (number) indicates Refers to the second number indicating the degree of protection: 0 No protection No special protection for outside people or objects IP-0 1 Prevent the intrusion of dripping water, vertical dripping water droplets (such as condensation water) will not cause harmful effects on the lamps IP-1 2 It can still prevent the intrusion of dripping water when it is tilted to 15°. When the lamp is tilted from vertical to 15°, dripping water will not have any harmful effect on the lamp. IP-2 3 It can prevent the intrusion of sprayed water, rain or the angle between the upper and the vertical is less than IP-3 4. Prevent water sprayed from 60° direction from entering the lamp and causing damage. IP-3 4. Prevent the intrusion of splashing water and prevent water splashing from all directions from entering the lamp and causing damage. IP-4 5. Prevent the intrusion of sprayed water from the nozzle from all directions. IP-5 6: Prevent the intrusion of large waves from intrusion of lamps and lanterns. For lamps installed on the deck, prevent damage caused by immersion in water due to the intrusion of large waves. IP-6 7: Prevent water intrusion during immersion. The lamps must be immersed in water for a certain period of time. If the time or water pressure is below a certain standard, it can ensure that it will not be damaged due to water ingress. IP-7 8 can prevent water intrusion during sinking. The lamp will sink indefinitely and the specified water pressure will ensure that it will not be damaged by water ingress. Cause damage IP-8 2.IP stands for Ingress Protection (ingress protection). The first marked number of the level, such as IP6_, indicates the dust protection level (6 means no dust ingress, see the table below). The second marked number, such as IP_5, indicates the waterproof protection level ( 5 indicates protection against water jets, see table below) Protection against intrusion of solid matter The first number defines Description Protection against intrusion of liquids – The second number defines Description 0 No protection. No special protection. 0 No protection. No special protection. 1 Protects against solid foreign objects with a diameter of 50mm and larger. Protects against objects with large surface areas such as hands (does not protect against intentional intrusion). 1 Protection against water droplets (vertically falling water droplets) 2 Protection against solid foreign objects with a diameter of 12mm and larger. Protect against fingers or other objects not exceeding 80mm in length. 2 When the equipment is tilted 15 degrees, it is protected from water drops. Vertically falling water drops should not cause damage. 3 Protects against solid foreign objects with a diameter of 2.5mm and larger. Protect tools, metal wires, etc. whose diameter or thickness exceeds 2.5mm. 3 Protect against splashing water. Water splashing from both sides of the vertical line at an angle of 60 degrees should not cause damage. 4 Protects against solid foreign objects with a diameter of 1.0mm and larger. Protect metal wires or strips with a thickness greater than 1.0mm. 4 Protection against water spray. Water spray directed at the equipment from any direction should not cause damage when the equipment is tilted 15 degrees from its normal position. 5 Protection from dust. It is impossible to completely prevent dust from entering, but the amount of dust that enters will not affect the normal operation of the equipment. 5 Protection against water jets. Water jets directed at the equipment from any direction should not cause damage. 6 Impermeable to dust. No dust enters. 6 Protection from big waves. The amount of water entering the equipment from large waves or strong jets should not cause damage. 7 Protection against water immersion. When immersed in water at defined pressures and times, there should be no intrusion of water in quantities capable of causing damage. 8 Protection against flooding. The device may be immersed in water for extended periods of time under the conditions specified by the manufacturer. The test method and main test conditions of the waterproof test (IP_5) are defined as follows: Test method – The inner diameter of the water outlet of the nozzle is 6.3mm, and it is placed 2.5-3m away from the test sample. Water flow rate – 12.5 l/min ±5 Test duration – 1 min/m2 but for at least 3 minutes.

Test conditions – spray the test sample from every feasible angle 3. In 8088 or 8086, IP (instruction pointer) refers to the instruction pointer register, which is a register inside the CPU used to store the offset of the next instruction to be executed Quantity, its value can be changed through the JMP instruction, for example: JMP AX uses the AX value to change the IP, thereby realizing jumps between segments. 4.Intellectual Property IP is the abbreviation of intellectual property, which means intellectual property (full name: intellectual property right). Intellectual property rights are an intangible property right, also known as the right to intellectual achievements. It refers to the results obtained through intellectual creative work, and is the exclusive right to the results enjoyed by intellectual workers in accordance with the law. Such rights include personal rights and property rights, also known as moral rights and economic rights. The so-called personal rights refer to rights that are inseparable from the person who has achieved intellectual achievements, and are the legal reflection of personal relationships. For example, the author's right to sign on his or her work, or the right to publish or modify his or her work, etc. The so-called property rights are the rights that the obligee can use the results of intellectual work to obtain remuneration or receive rewards after the results of intellectual work are recognized by law. This right is also called economic rights. The object of intellectual property protection is the human mind and human intelligence. Creation is a person's right to intellectual achievements. It is the legal right to intellectual achievements created by engaging in all intellectual activities in the fields of science, technology, culture, and art. Intellectual property is a legal concept widely used internationally. Intellectual property rights include industrial property rights and copyright (called copyright in our country). Industrial property rights include patents, trademarks, service marks, manufacturer names, names of origin, suppression of unfair competition, etc. Copyright is the legally stipulated right for a certain unit or individual to print, publish and sell a certain work. Anyone who wants to copy, translate, adapt or perform must obtain the permission of the copyright owner, otherwise it will be an infringement of the rights of others. Behavior. The essence of intellectual property rights is to treat human intellectual achievements as property. Trademark rights refer to the exclusive rights granted by the trademark authorities to trademark owners to protect their registered trademarks under national laws. A trademark is a commercial sign used to distinguish goods and services from different sources. It consists of words, graphics, letters, numbers, three-dimensional signs, color combinations, or a combination of the above elements. To obtain trademark rights in my country, the trademark registration procedure must be followed, and the first-to-file principle must be implemented. Copyright is a civil right enjoyed by the original creator of literary, artistic, scientific and technological works in accordance with the law. Patent rights and patent protection refer to an invention-creation that submits a patent application to the National Patent Office, and after passing the examination in accordance with the law, the patent applicant is granted the exclusive right to the invention-creation within a specified period of time. After an invention is granted a patent, the patentee has exclusive rights to the invention. No unit or individual may exploit the patent without the permission of the patentee, that is, they may not manufacture, use, offer for sale, or sell the invention for production and business purposes. Sells and imports its patented products. Exploiting the patent without the permission of the patentee will infringe upon the patent right. If a dispute arises, it shall be resolved by the parties through negotiation; if the parties are unwilling to negotiate or the negotiation fails, the patentee or a closely related person may sue the People's Court or request management. The department handles patent work. Patent protection adopts a protection model of “two channels, parallel operations, and judicial guarantee” of judicial and administrative law enforcement. Administrative protection in this region adopts the form of patent enforcement in the form of roving enforcement and joint enforcement, concentrating efforts and focusing on intensifying the crackdown on group infringement, repeated infringement and other phenomena that seriously disrupt the patent legal environment. Three characteristics of intellectual property rights: 1. The exclusivity of intellectual property rights, that is, exclusivity or monopoly; 2. The regional nature of intellectual property rights, that is, it is only valid within the confirmed and protected area; 3. The temporal nature of intellectual property rights, That is, protection is only provided for a specified period.

IP abbr. 1. =Internet Protocol Computer International Internet Communication Protocol 5. A police rank of the Hong Kong police. IP is the abbreviation of Inspector (Inspector of Police): squad commander. 6. The abbreviation of Interpol, ip, is also the abbreviation of International Criminal “P”olice Organization. 7. Intellectual property core (module) The use of IP (Intellectual Property) on-chip is an important feature of building a SOC. IP is defined as a pre-designed circuit function module used in ASIC or FPGA/CPLD. IP is divided into soft IP, fixed IP and hard IP. Soft IP core: Function module described in Verilog HDL. Solid IP core: Comprehensive functional modules are completed, with a large depth of involvement, and are submitted to customers in the form of netlist files. Hard IP core: Provides the final product of the design - mask.

[Edit this paragraph]IP register

IP (Interrupt Priority) Interrupt priority control register The interrupt priority control register IP in the MCS-51 microcontroller is the user's interrupt priority control service program until the end of the program, execute the last return instruction to return to the main program, and then execute the basis of the next instruction. If a bit in IP is set to 1, the corresponding interrupt is set to high priority, otherwise it is set to low priority. The format of the interrupt priority control register is as follows: IP D7 D6 D5 D4 D3 D2 D1 D0

/ / / PS PT1 PX1 PT0 PX0

Bit address / / / BCH BBH BAH B9H B8H

The meaning of IP valid control bits: PX0: Interrupt priority control bit of external interrupt 0, PX0=1, external interrupt 0 is defined as a high-priority interrupt; PX0=0, external interrupt 0 is defined It is a low priority interrupt. PT0: Interrupt priority control bit of timer/counter T0. PT0=1, timer/counter T0 is defined as a high-priority interrupt; PT0=0, timer/counter T0 is defined as a low-priority interrupt. PX1: Interrupt priority control bit of external interrupt 1, PX1=1, external interrupt 1 is defined as a high-priority interrupt; PX1=0, external interrupt 1 is defined as a low-priority interrupt. PT1: Interrupt priority control bit of timer/counter T1. PT1=1, timer/counter T1 is defined as a high-priority interrupt; PT1=0, timer/counter T1 is defined as a low-priority interrupt. PS: Serial port interrupt priority control bit, PS=1, the serial port interrupt is defined as a high-priority interrupt; PS=0, the serial port interrupt is defined as a low-priority interrupt.