Mobile phones are a kind of MCU, but the hardware it uses is not 51 chip

Now the higher the automation of the plant PLC The more , Now many factories will organize highly educated maintenance personnel to study PLC, Unfortunately, there are too few professional counterparts , Talk to each other .

Now most of the single-chip computers are directly applied to product development , If you open Taobao and look at smart toys, you will know how widely it is used , Even mobile phones are a kind of MCU , But the hardware it uses is not 51 Chip , Software is not the programming language I learned .

however 51 SCM can be said to be the foundation of the foundation , even 51 I don't know , It's estimated that a higher level will be very tired . 

PIC Single chip microcomputer

PIC MCU series is American micro chip company （Microship） Products , There are three levels , Basic level 、 intermediate 、 senior , It is one of the fastest growing single chip computers in the current market share ,CPU use RISC structure , There were 33、35、58 Orders , Is a reduced instruction set , Simultaneous adoption Harvard Dual bus structure , Fast running speed , It can make program memory access and data memory access

The article is relatively long , More words , You can first open the avatar and pay attention to me , Then take your time ,/// Insert a ： At the beginning of this year, I recorded a set of systematic introductory single chip microcomputer tutorial , If you want, just ask me for it. It's free , I can send a private message ~ Click the black font in the lower left corner of my avatar and I can also get it . I've been relatively idle recently , Take me to finish the design , Take students to provincial or above competitions ///

parallel processing , This instruction pipeline structure , Complete two parts of the work in one cycle , One is to execute instructions , The second is to take out the next instruction from the program memory , In general, each instruction only needs one cycle , This is also One of the reasons for efficient operation , Besides PIC The reason why the single-chip computer has become a very hot single-chip computer is nothing more than the following characteristics ：

characteristic ：

1. With low working voltage 、 low power consumption 、 Driving power and other characteristics .PIC A series of single chip computers I/O The mouth is two-way , Its output circuit is CMOS Complementary push-pull output circuit .I/O The pin adds a direction register for setting the input or output state , So it solved 51 series I/O The foot is in the state of input and output when the electricity is high .

2. When set 1 Is the input state , And no matter the pin is high or low , All of them are in high resistance state ; Set up 0 Is the output state , Regardless of the level of the pin , All of them are in low resistance state , There is considerable driving power , Low level suction current up to 25mA, High level output current up to 20mA. be relative to 51 In terms of series , This is a great advantage

3. It can directly drive the nixie tube display and the external circuit is simple . its A/D by 10 position , It can meet the accuracy requirements . With online debugging and programming （ISP） function .

deficiencies ：

Its special register （SFR） Don't like 51 Series like that are concentrated in a fixed address range （80～FFH）, It's spread over four address ranges . Only 5 Special registers PCL、 STATUS、FSR、PCLATH、INTCON stay 4 All of them are present at the same time , But in the process of programming , It's necessary to deal with special registers , You have to select the corresponding storage repeatedly

That is to say, for the state register STATUS Of the 6 position （RP1） And the 5 position （RP0） To set or clear . Data transmission and logical operation basically have to go through the working register W（ amount to 51 Accumulation of series device A） To carry out , and 51 Series can also be directly transmitted to each other through registers , thus PIC The bottleneck phenomenon of single-chip microcomputer 51 The series is serious , This in the programming of friends should have a deep understanding of

The most used devices ：PIC16F873、PIC16F877

PIC SCM is based on RISC Single chip microcomputer of system structure , The original design was to support PDP( Programming data processor ) Computer . A large number of operations can be used to control peripheral devices .

pic Principle and application of single chip microcomputer

PIC MCU has faster program execution ability than microcontroller . It was developed by microchip technology company in 1889 Invented in , It's a kind of 8 Bit MCU . as everyone knows , SCM is actually a processor , A combination of memory and peripherals in a single chip .PIC Single chip microcomputer uses data RAM And hundreds ROM Store the required program in a similar way ROM, some I/O port , One has 8 A pin timer .

It is called peripheral interface controller , Because it is designed to execute simple control applications . But now , It is often called a programmable intelligent computer . as everyone knows , The components of single chip microcomputer are basically embedded in the chip . therefore , External memory 、I/O Ports or timers cannot be added further . However , This attribute is also used in various applications of single chip computers .

Whenever we talk about embedded systems , Obviously , Although there are external controllers , But they still have internal microcontrollers . MCU in embedded system ROM Usually, the functions that the storage system wants to perform .

As we discussed , It consists of a processor 、I/O port 、 Timer and memory organization .