4 layers of circuit board processing

Single chip emulator is a set of hardware device specially designed and manufactured for the purpose of debugging single chip software.

SCM is the same as PC in the architecture, also includes * processor, input/output interface, memory and other basic units, so the software structure of PC and other devices is similar. Therefore, microcontroller in the process of software development also need to debug the software, observe the results, eliminate the problems in the software. However, due to the application of the microcontroller problem, it does not have a standard input and output device, limited by storage space, it is difficult to accommodate the software used for debugging procedures, so to debug the microcontroller software, the use of microcontroller simulator. 

Single chip emulator has the basic input and output device, with the support of program debugging software, so that the single chip developer can input and modify the program through the single chip emulator, observe the results of the operation of the program and the intermediate value, at the same time with the single chip supporting hardware detection and observation, can greatly improve the efficiency and effect of single chip programming.

The early single-chip emulator was a set of vertical devices with a keyboard and a display for inputting programs and displaying running results; With the popularity of the PC, most of the new generation of emulators are using the PC as the standard input and output device, and the simulator itself becomes the interface between the computer and the target system, the simulation way also from the beginning of the machine code development to assembly language, C language simulation, simulation environment and the PC language programming and debugging environment is very similar.

The simulator generally has a simulation head, used to replace the target system in the single chip microcomputer, that is, use the plug to imitate the single chip microcomputer, which is the name of the single chip emulator.

At present, with the microcontroller miniaturization, chip and the wide application of the microcontroller with ISP, IAP and other functions, the application range of the traditional microcontroller simulator has been reduced. And software SCM simulator (that is, SCM simulation program) is widely used, SCM simulation program is running on the personal computer, can simulate the hardware environment of SCM operation to a certain extent, and in the environment to run SCM target program, and can debug the target program, breakpoint, variable observation and other operations, It can greatly improve the debugging efficiency of SCM system. Pure software single-chip emulator is often integrated with the hardware design program released together, so that ** can develop the single-chip hardware and software synchronously.

(1) Manual manufacturing process of printed circuit board A basic process of manual manufacturing of PCB is the transfer of the designed PCB to the copper clad plate. The simple and effective method, etching, uses a protective anti-corrosion material to form a pattern on the copper-covered plate. Unwanted copper foil is removed with chemical corrosion. At the end of the corrosion, the resist layer is washed away so that the pattern can be seen.

(2) Factory production process of printed circuit boards Factory production of printed circuit boards need to go through complicated processes. In the production process, each technology has a clear operation method, in addition to the production of negatives, hole metallization and graphic plating etching is the key to production. Printed circuit original base map production method: for printed circuit board, what method is the best to meet the quality requirements of 1: There are two sources of original negatives: one is to make a photographic base and get the original negatives after taking photos; the other is to draw the original negatives directly by using computer system and optical drawing machine. PCB printing and etching and process: There are two general methods for making the mask graphics of corrosion resistance or electroplating: Screen leakage and photosensitive dry film method. Screen leakage method is generally used for single or double sided PCB production with large batch and low single precision, which is convenient for automation. The photosensitive dry film method is mainly to improve the production efficiency, simplify the process and improve the quality of the plate.

As a microelectronic IC learner, there is also a course in this semester: "Microelectronic devices", today I will talk about the basic devices: CMOS devices and circuits. We'll talk about latches and triggers later.

Today's main content is as follows:

· Brief introduction of MOS transistor structure and working principle

·CMOS unit circuit and layout

·CMOS gate circuit

· Power representation of CMOS

To be honest, CMOS is more micro electronic devices, micro electronic devices are really difficult... Here are a few things you might want to know about doing digital design