pcb identifier

cpus_runnable is 0, otherwise 1 This value is updated when the running queue is lockedunsigned long cpus_runnable, cpus_allowed;Pointer to run queuestruct List_head run_list;Sleep time of the processunsigned long sleep_time;Used to connect all processes in the system into a two-way circular linked list whose root is Init_taskstruct task_struct *next_task, *prev_task;struct Mm_struct *active_mm;struct List_head local_pages; Point to Local pageunsigned int allocation_order, nr_local_pages;struct

Address: http://pda.c114.net/164/a565914.html Introduction Signal integrity refers to the signal quality in the circuit system. If the signal can be sent from the source end to the receiving end without losing sight within the required time, it is called that the signal is complete. With the rapid development of semiconductor technology, the output speed of IC switches is improved, and the signal integrity problems (including signal overshoot and underloading, ringing, reflection, crosstalk, an

The testability concept of PCB DesignThe testability of the product design (De sign for testability. OFT) Product manufacturability is also the main content from the production point of view is also one of the design process. It refers to the design of the product performance can be considered difficult to detect, that is, design products should consider how to use the simplest method of product performance and processing quality testing, or product d

This article is reproduced on the Internet and is only for personal learning. The copyright belongs to the original work. 1. when you start to draw a PCB, please do not arrange your high-frequency cabling according to the common signal line. It is the right way to obtain the reference design from the chip manufacturer. the general chip data manual or related manual will have a high frequency part of the line reference. 2. High-frequency line

PCB Cabling 6 Major principles1 power, ground processing not only in the entire PCB board in the wiring is done well, but due to the power, grounding the consideration of the interference caused by, will make the performance of the product decline, and sometimes even affect the success rate of the product. Therefore, the wiring of electricity, grounding wire to be taken seriously, the electricity, ground no

Sinox, Macau, China many platform CAD graphics, PCB board, IC I know, HDL hardware description Language narrative, circuit simulation and design software, elemental analysis table, can open the eyes of the world.Recent research Sinox the implementation of Windows edition Protel,powerpcb,autucad, which is considered very cumbersome. On the other thought, Sinox the following in fact there are a lot of auxiliary design software available, but we do not k

PCB packaging is mainly divided into SMD and plug-in type1) SMD Component Package DescriptionLED: color has red, yellow, green, blue points, brightness divided Puliang, highlighting, super bright three and so onClass, the commonly used package form has three types: 0805, 1206, 121 (commonly used package is rb.1/.2)the extension is: 0805C, 0805D, 0805L, etc. Diode: According to the limit of the current withstand, the package form is broadly divide

, when the clock frequency exceeds 100 MHz or the rising edge is less than 1 ns, the signal integrity effect becomes important. In PCB, the signal line is the main carrier for signal transmission. The cabling of the signal line directly determines the superior signal transmission, thus directly affecting the performance of the entire embedded system. Unreasonable wiring will seriously lead to various signal integrity problems, and generate timing, noi

--------------------------------------------------------------------------------------------------------------- ---------------------Sheet TechnologyThe following parameters or tables represent only part of the plate process and simulation selection parameters, the actual production will have a certain difference (but not a small deviation!). ）The simulation software uses Polar's "Si9000".1oz=28.35g,1oz copper thickness refers to 1 square feet of area on average copper foil weight equa

1-2 is omited, for more detail please referWww.usb.org. ....... 3 layout guidelines 3.1 General Routing and placementUse the following general routing and placement guidelines when laying out a new design. TheseGuidelines will help to minimize signal quality and EMI problems. The high speed USB validation effortsFocused on a four-layer motherboard where the first layer is a signal layer, the second layer is power,Third layer is ground and the fourth is a signal layer. This results in placing mos

During circuit design, there are more and more power supplies and multiple locations on a PCB, such as 48 V, 12 V-Common types of power supplies such as 12 V, 5 V,-5 V, 3.3 V, 2.5 V, 1.8v1.v, agnd (analog location) dgnd (Digital location), pgnd (Protected Area) the ground plane required for different functions, some IC clearly requires the single point grounding, and the required power supply, ground plane hollowing. In order to ensure high reliabilit

When drawing a PCB, you often need to check the corresponding components on the schematic. If the number of components is small, you can find them. Also, alicloud designer provides a good cross-search function. Here I suggest using two monitors, one with a schematic diagram and the other with a PCB, which makes it easier to find out. 1 use the shortcut key T + c This shortcut key is used in both the schem

Formula for propagation delay of cabling in PCB The first half is information from altera. The propagation latency (tPD) is the time required to transmit a signal from one point to another. Transmission Line propagation delay is a function of the relative dielectric constant of materials. Propagation delay of micro-Strip Layout You can use formula 5 to calculate the propagation delay of the strip layout. Formula 5: Delayed propagation in the line

Shortcut Keys for protel99 and power PCB (pads layout)Shortcut for protel99 I. Principle Image Library P/P: Draw component pins P/A: draw an arc P/L: draw a straight line P/A: Draw a rectangle T/C: Create a new component T/R: Delete the component T/E: Rename the component t/W: Create a new child for the component T/T: delete a child of the component Ii. Schematic diagram CTRL + backspace: Repeat the previous operation Ctrl + backspace: cancel the pre

Note: belong to reprint Many people for the PCB traces of the reference plane is confused, often asked: for the inner layer traces, if the line side is VCC, the other side is GND, then which is the reference plane? To figure this out, you have to understand the concept of transmission lines. We know that the transmission line must be used to analyze the signal transmission on the PCB in order to explain th

transistors and variable resistors, their packaging is the most headache, the same packaging, its pin is not necessarily the same. For example, for packaging such as to-92b, usually 1 feet is e (emitter), and 2 feet may be B-pole (base), or C (collector), the same, 3 feet may be C, also may be B, specifically that, only to get the components can be determined. Therefore, the circuit software is not hard to define the name of the pad (pin name), the same, FET, MOS tube can also be used in the sa

A process is a dynamic description of a program, which is the smallest unit of the operating system's resource allocation (the thread is the smallest unit of the operating system execution entity). for a multi-channel program system, there may be many processes in memory, in order to facilitate the management of these processes, the operating system kernel for each created process to establish a structure to save its related information. This structure is the

High Frequency Circuit Wiring techniques in PCB Layout 1. Multi-board wiring High-frequency circuits often have a high degree of integration and a high wiring density. Using a multi-layer board is not only required for wiring, but also an effective means to reduce interference. In the PCB Layout stage, a proper selection of printing board sizes of a certain number of layers can make full use of the middle

Because COB does not have IC sealed Leadframe (Guide frame), but uses the PCB to replace, so the PCB welding mattress design Handy is very important, and fihish can only use electricity plated gold or enig (isotopes leaching gold), whether the Gold line or aluminum line, Even the latest brass lines have problems that can't be beaten up.PCB Design requirements for COB The finished surface of PC board

Address: http://blog.csdn.net/qq736934266/article/details/3582764 1. General rules1.1 Pre-division of digital, analog, DAA signal cabling areas on the PCB.1.2 numbers, analog components and corresponding cabling should be separated and placed in their respective cabling areas as far as possible.1.3 high-speed digital signal cabling as short as possible.1.4 The sensitive analog signal must be as short as possible.1.5 reasonably allocate power supplie