PCB Mekhoa ea wiring e ntse e tsoela pele ho ntlafala, ‘me mekhoa e metle ea mehala e ka fokotsa bolelele ba terata le ho lokolla sebaka se seng sa PCB. Mehala e tloaelehileng ea PCB e lekantsoe ke likhokahanyo tsa terata tse sa fetoheng le khaello ea likhoele tse sekameng ka mokhoa o ikhethileng. Ho tlosa mefokolo ena ho ka ntlafatsa haholo boleng ba wiring.

Let’s start with some terminology. Re hlalosa mohala o fapaneng oa Angle joalo ka likhoele tsa terata re sebelisa likarolo tsa Angle le mahlaseli. Ke mofuta oa terata ea terata, empa ha e felle feela ho sebelisa likarolo tsa 90 degree le 45 degree Angle line. Topological wiring is wire wiring that does not adhere to grids and coordinates and does not use regular or irregular grids like shape-based wiring. Ha re hlaloseng poleloana e reng, wiring e fetohang joalo ka terata e se nang sebopeho se sa fetoheng se nolofalletsang likhakanyo tsa nako ea terata ho fihlela menyetla e latelang ea phetoho. Ke li-arcs feela tsa litšitiso le li-tangents tsa bona tse tloaelehileng tse sebelisoang ho theha sebopeho sa mola. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Mehala e metala le e mefubelu e matha ka mekhahlelo e fapaneng ea mofuta oa PCB. The blue circles are the perforations. The red element is highlighted. There are also some red round pins. Use only line segments and models with an Angle of 90 degrees between them. Setšoantšo sa 1B ke mofuta oa PCB o sebelisang li-arcs le likhutlo tse hatellang. Wiring at any Angle may seem strange, but it does have many advantages. The way it is wired is very similar to how engineers wired it by hand half a century ago. E bonts’a PCB ea ‘nete e ntlafalitsoeng ka 1972 ke k’hamphani ea Amerika e bitsoang Digibarn bakeng sa likhoele tse felletseng tsa letsoho. This is a PCB board based on Intel8008 computer. Mehala ea Angle e hatellang e bontsitsoeng ho Setšoantšo sa 2 e hlile ea tšoana. Hobaneng ha ba ka sebelisa mohala oa Angle o hatellang? Hobane mofuta ona oa wiring o na le menyetla e mengata. Arbitrary Angle wiring has many advantages. Taba ea mantlha, ho se sebelise li-angles lipakeng tsa likarolo tsa line ho boloka sebaka sa PCB (li-polygone kamehla li nka sebaka se fetang sa tangents). Traditional automatic cablers can place only three wires between adjacent components (see left and center in Figure 3). Leha ho le joalo, ha o hokahanya mohala ho Angle efe kapa efe, ho na le sebaka se lekaneng sa ho beha lithapo tse 4 tseleng e le ‘ngoe ntle le ho tlola melao ea moralo (DRC). Ha re re re na le mokhoa o nepahetseng oa chip ‘me re batla ho hokahanya lithakhisa tsa chip le lithakhisa tse ling tse peli. Using only 90 degrees takes up a lot of space. Ho sebelisa mohala oa Angle o hatellang ho ka khutsufatsa sebaka se pakeng tsa chip le lithakhisa tse ling, ha o ntse o fokotsa leoto. In this case, the area was reduced from 30 square centimeters to 23 square centimeters. Ho potoloha chip ka Angle efe kapa efe ho ka fana ka liphetho tse betere. In this case, the area was reduced from 23 square centimeters to 10 square centimeters. It shows a real PCB. Arbitrary Angle wiring with rotating chip function is the only wiring method for this circuit board. Hona ha se khopolo feela, empa hape le tharollo e sebetsang (ka linako tse ling ke eona feela tharollo e ka bang teng). Shows an example of a simple PCB. Litholoana tsa cable ea topology, ha liphetho tsa cabler tse iketsang li ipapisitse le sebopeho se nepahetseng ke linepe tsa PCB ea ‘nete. An automatic cabler based on optimal shape cannot do this because the components are rotated at arbitrary angles. U hloka sebaka se eketsehileng, ‘me haeba u sa potolohe likarolo, sesebelisoa se tlameha ho holisoa. Layout performance would be greatly improved without parallel segments, which are often a source of crosstalk. The level of crosstalk increases linearly as the length of parallel wires increases. As the spacing between parallel wires increases, crosstalk decreases quadratic. Let’s set the level of crosstalk produced by two parallel 1mm wires spaced d to e. Haeba ho na le Angle lipakeng tsa likarolo tsa terata, joale ha Angle ena e ntse e eketseha, boemo ba crosstalk bo tla fokotseha. The crosstalk does not depend on the length of the wire, but only on the Angle value: where α represents the Angle between the wire segments. Nahana ka mekhoa e meraro e latelang ea wiring. On the left side of Figure 8 (90 degree layout), there is the maximum wire length and the maximum emi value due to parallel line segments. In the middle of Figure 8 (45 degree layout), the wire length and emi values are reduced. On the right-hand side (at any Angle), the wire length is shortest and there are no parallel wire segments, so the interference value is negligible. So arbitrary Angle wiring helps to reduce the total wire length and significantly reduce electromagnetic interference. You also remember the effect on signal delay (conductors should not be parallel and should not be perpendicular to the PCB fiberglass). Advantages of flexible wiring Manual and automatic movement of components does not destroy the wiring in flexible wiring. Cabler e ipapisa le sebopeho se nepahetseng sa terata (ho nahanoa ka tumello e hlokahalang ea polokeho). Ho fofa habonolo ho ka fokotsa haholo nako e hlokahalang ho hlophisa topology, ho ts’ehetsa hantle li-recaction tse ngata ho fihlela mathata. Sena se bontša moralo oa PCB o tsamaeang ka masoba le lintlheng tsa lekala. Nakong ea motsamao o iketsang, lintlha tsa makala a terata le likoti li phunyeletsoa hore li be boemong bo nepahetseng. In most computer-aided design (CAD) systems, the wiring interconnection problem is reduced to the problem of sequentially finding paths between pairs of points in a maze of pads, forbidden areas, and laid wires. Ha tsela e fumanoa, e lokisoa ebe e fetoha karolo ea maze. Bothata ba wiring e latellanang ke hore sephetho sa wiring se ka itšetleha ka tatellano ea wiring. Ha boleng ba topological bo ntse bo sa phethahala, bothata ba “ho ts’oaroa” bo hlaha libakeng tse nyane tsa lehae. But no matter which wire you rewire, it’s not going to improve the quality of the wiring. This is a serious problem in all CAD systems using sequential optimization. This is where the bending elimination process is useful. Ho kheloha ka terata ho bolela ntho e makatsang ea hore terata e neteng e le ‘ngoe e tlameha ho tsamaea ho potoloha ntho ho netweke e ngoe ho fihlela ntho. Rewiring a wire will not correct this. Ho bontšoa mohlala oa ho koba. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Liphetho tse iketsang tsa ts’ebetso li bonts’itsoe. In the second case (on another layer), a lighted green wire is automatically rewired by changing the wiring layer (from green to red). Eliminate wire bending by automatically optimizing wire shape (approximate arcs with line segments just to show any Angle examples without arcs). (top) original design, (bottom) after eliminating bending design. Ho totobatsoa lithapo tse khubelu. Sefateng sa Steiner, mela eohle e tlameha ho hokahanngoa joalo ka likarolo ho li-vertices (li-endpoints le litlatsetso). Karolong e kaholimo ea vertex e ncha, likarolo tse tharo li tlameha ho kopana mme likarolo tse fetang tse tharo li tlameha ho fela. The Angle between the line segments that converge to the vertex shall not be less than 120 degrees. Ha ho thata haholo ho aha Steiner ka thepa ena e nang le maemo a lekaneng, empa ha se hakaalo hore e nyane. Gray Steiner trees are not optimal, but black Steiner trees are. Ka moralo oa puisano o sebetsang, mefuta e fapaneng ea litšitiso e tlameha ho tsotelloa. Ba lekanyetsa bokhoni ba ho aha bonyane ba lifate tse haolang tse sebelisang algorithms ka bobeli le lifate tsa Steiner ba sebelisa mekhoa ea jiometri. The obstacles are shown in gray and we recommend starting at any end vertex. If there is more than one adjacent terminating vertex, you should choose one that allows you to continue using the second vertex. It depends on the Angle. Mochini o ka sehloohong mona ke algorithm e nang le matla e lekanyetsang matla a sebetsang linthong tse ncha ebe a a suthisetsa makhetlo a lekanang (boholo le tataiso ea mabotho li ipapisitse le lithapo libakeng tse haufi tsa lekala). Haeba Angle lipakeng tsa likarolo tsa line tse hokahantsoeng le vertex (terminus kapa addition) e ka tlase ho likhato tse 120, ntlha ea lekala e ka eketsoa, ​​ebe ho ka sebelisoa algorithm ea mochini ho ntlafatsa boemo ba vertex. It’s worth noting that simply sorting all angles in descending order and adding new vertices in that order doesn’t work, and the result is worse. After adding a new node, you should check the minimum of a subnet consisting of four pins:

1. If a vertex is added to the vicinity of another newly added vertex, check for the smallest four-pin network.

2. If the four-pin network is not minimal, select a pair of “diagonal” (belonging to the quadrilateral diagonal) endpoints or virtual terminal nodes (virtual terminal nodes – wire bends).

3. The line segment that connects the endpoint (virtual endpoint) to the nearest new vertex is replaced by the line segment that connects the endpoint (virtual endpoint) to the distant new vertex.

4. Use mechanical algorithms to optimize vertex positions.

This method does not guarantee to build the smallest network, but compared with other methods, it can achieve the smallest network length without grazing. E boetse e lumella libaka tseo likamano tsa bofelo li thibetsoeng, ‘me palo ea libaka tsa ho qetela e ka ba tse ikhethileng.

Flexible wiring at any Angle has some other interesting advantages. For example, if you can automatically move many objects with the help of automatic real-time wire shape recalculation, you can create parallel serpentine lines. This cabling method makes better use of space, minimizes the number of iterations, and allows for flexible use of tolerances. If there are two serpentine lines interlaced with each other, the automatic cabler will reduce the length of one or both, depending on rule priority.

Consider the wiring of BGA components. In the traditional peripheral-to-center approach, the number of channels to the periphery is reduced by 8 with each successive layer (due to a reduction in perimeter). For example, a 28x28mm component with 784 pins requires 10 layers. Likarolo tse ling tsa setšoantšo se balehile ka likhoele. Setšoantšo sa 16 se bonts’a kotara ea BGA. Ka nako e ts’oanang, ha o sebelisa “wiring to periphery” method wiring, palo ea liteishene tse hlokoang ho tsoa moeling ha e fetohe ho tloha mokatong o mong ho ea ho o mong. Sena se tla fokotsa haholo palo ea likarolo. Bakeng sa boholo ba karolo ea 28x28mm, mekato e 7 e lekane. Bakeng sa likarolo tse kholo, ke win-win. Figure 17 shows a quarter of the BGA. An example of BGA wiring is shown. When using the “center to periphery” cabling approach, we can complete the cabling of all networks. Ka mokhoa o ikhethileng Angle topological jarolla ka ho iketsa cabler e ka etsa sena. Traditional automatic cablers cannot route this example. Shows an example of a real PCB where the engineer reduced the number of signal layers from 6 to 4 (compared to the specification). In addition, it took engineers only half a day to complete the wiring of the PCB.