Technical
How to Judge the Acceptance of PCB Quality
Which Color Circuit Board Sells the Most Expensive
Method to Solve the Noise Interference of Power Supply on High-frequency PCB Board
Disassembly Skills of Chip Components on PCB
What Factors Should Be Considered in the Selection of High-frequency PCB CCL
How to Place Special Components during PCB Layout
What Are the Functions of Capacitors in Circuits?
Testing Techniques for Common Electronics Components
What to do if There is a Short Circuit on the PCB
Desoldering Principles and knowhow during PCBA Processing
Black Oxidation of the Inner Layer of the Multilayer PCB
How to Ensure the High-performance Design of PCB
What Is the Printing Process of SMT Solder Paste?
PCB without fiducial mark, Is There Any Way to do SMT for It
What Are the Benefits of Reserving Break-up Tab for PCB Production
How Does SMT Affect PCB Production Time and Speed It Up
Classification of PCBs from three aspects
Common Problems and Solutions for Dry Film pasting during PCB Manufacturing process
Several Elements to Inspect after PCB Design
What is a halogen-free circuit board?
What Do Capacitive Coupling and Decoupling Mean?
What Are the Differences Between PCB Paste Mask and Solder Mask?
How PCBA Is Packaged and Shipped
How long can PCBA finished products be stored?
What Are the Differences and Relations Between PCB, PCBA, and SMT?
PCB Baking Specifications
PCB "Solder Mask Tenting" and "Solder Mask Opening"
Five reasons for PCB deformation and six solutions
Importance of first article inspection of PCBA board
Temperature zone standard for SMT reflow soldering
Small and medium volume PCB manufacturers in China
The main reason for PCBA cleaning
For power filter, the more capacitors, the better?
What does PCBA programming mean?
Content of PCB incoming testing
What conditions must be met for PCB circuit board soldering?
What is Blind via and Buried via
PCBA Manufacturers Temperature and Humidity Sensitive Components Management
Why choose Shenzhen SMT processing factory?
How long does it take to calculate the quotation for PCBA manufacturing?
Introduction of PCB design clearance requirements
Explanation of BOM, DIP, SMT, SMD
Introduction of the process of PCBA prototype
How to prevent pseudo soldering or cold soldering defects in PCBA manufacturing?
Factors that affect the Price of FPCB
What information is required for SMT processing at PCBA factory?
Skills of using 0ohm resistor in PCB design
How to select a PCBA manufacturer
SMT processing solder joint quality inspection
Characteristics difference between immersion gold PCB and gold plating PCB
Common malfunctions of Circuit Board Caused by Moisture
A Few Rules about PCB Panelization
Compare of multi-layer PCB with single/double layer PCB
Why do we need to introduce so many subdivided GND
Difference between immersion gold boards and gold plating boards
Aluminum PCB structure
Classification of different GND in circuit
Why PCB baking is necessary during manufacturing process
The handle and precautions of OSP board in SMT process
How to choose capacitors for filter decoupling
How to choose filter capacitor for switching power supply
5 database need for SMT process
Function of three-terminal capacitor
Introduction of PCB OSP surface treatment
Method of inspecting the quality of SMT by step
How to find the short point between VCC and GND
Difference between 850nm and 940nm infrared LED
Component layout of PCB SMT DFM
Pad shape influence on the strength and reliability of the soldering joints
The difference between high temperature solder paste and low temperature solder paste
Introduction to manual welding processing
Manual visual inspection in PCBA processing
Characteristics of the conformal coating process
Difference between hardware engineers and software engineers
PCBA processing operation rules
China PCB upstream materials has continued to soar
Difference between serial buses and parallel buses
The key points of quality control in PCBA processing
Common causes of solder beading during SMT process
Analysis of the advantages and disadvantages of HASL PCB surface
Requirements for layout of components during SMT assembly
Selection of electronic components and CCL for PCBA
Performance and appearance quality inspection of components.
Quality and Reliability of SMT Chip Processing and Production
Coupling and decoupling function of capacitor
Two methods to connect digital ground and analog ground
Common sense in SMT process

Difference between serial buses and parallel buses

What are serial buses and parallel buses?

Literally, serial means sending data one by one, and parallel means sending data in groups.

The memory chip DDR is a parallel transmission. It has a set of data lines D0-D7, plus DQS, DQM. This set of lines is transmitted together. As long as one of the lines is wrong, the data cannot be transmitted correctly and needs to be retransmitted. The serial data is transmitted bit by bit, and there is no connection between bit and bit, don’t have situation that the next bit cannot be transmitted because of an error in this bit.

Old-fashioned devices in the early years all used parallel transmission, while current devices all use serial transmission. Why is parallel transmission replaced by serial transmission?

Parallel bus
Parallel buses need to consider the cooperativity of data because multiple data are transmitted at the same time, which leads to the fact that the frequency of parallel transmission cannot be made very high. In contrast, the serial bus has only one link, so the frequency can be made very high, and the transmission speed can be increased. The increased speed can make up for the defect that only one data can be transmitted at a time.

In addition, the data of two adjacent links of the parallel bus are transmitted at the same time, which will cause serious interference between them. The more parallel links, the stronger the interference. Therefore, the parallel bus needs to strengthen the anti-interference ability, otherwise the data may be damaged during the transmission. If the data fails during the transmission, the data needs to be realigned and then transmitted. However, if a data error occurs on a serial bus, it only needs to be retransmitted once. Due to the high frequency of the serial bus, the erroneous data can be retransmitted soon.

Thirdly, because the parallel bus is a multi-link data transmission, it needs a lot of wires and the interface needs a lot of pins. The parallel interface in the old computer is very large, the wiring is relatively wide, and many pins are needed. In this way, the installation is also very troublesome, because the wiring is inconvenient and the interface is large.

It is precisely because of these shortcomings that the computer bus has gradually changed from parallel transmission to serial transmission, such as USB, hard disk SATA, and so on.

It should be noted that the gold fingers on the bottom of the graphics card PCB are densely packed in a large row, and the interface is PCIE x16, which looks like a parallel bus, but is actually a serial bus. The serial bus can be used for multi-link transmission. Unlike parallel links, each of its links is independent data, which has nothing to do with each other and will not be interfered by other data.