PCB metode ožičenja se še naprej izboljšujejo, prilagodljive tehnike ožičenja pa lahko skrajšajo dolžino žice in sprostijo več prostora na tiskani vezji. Običajno ožičenje tiskanih vezij je omejeno s fiksnimi koordinatami žic in pomanjkanjem poljubno nagnjenih žic. Odprava teh omejitev lahko bistveno izboljša kakovost ožičenja.

Let’s start with some terminology. Določimo poljubno kotno ožičenje kot žično ožičenje z uporabo poljubnih kotnih segmentov in radianov. To je neke vrste žično ožičenje, vendar ni omejeno na uporabo samo segmentov 90 -stopinjskega in 45 -stopinjskega kota. 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. Opredelimo izraz fleksibilno ožičenje kot žično ožičenje brez fiksne oblike, ki omogoča ponovni izračun oblike žice v realnem času, da se dosežejo naslednje možnosti transformacije. Za obliko črte se uporabljajo samo loki ovir in njihove skupne tangente. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Zelena in rdeča žica potekata na različnih plasteh modela 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. Slika 1B je model tiskane plošče z loki in poljubnimi koti. 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. Prikazuje pravo PCB, ki jo je leta 1972 razvilo ameriško podjetje Digibarn za popolno ročno ožičenje. This is a PCB board based on Intel8008 computer. Samovoljno kotno ožičenje, prikazano na sliki 2, je dejansko podobno. Zakaj bi uporabili poljubno kotno ožičenje? Ker ima ta vrsta ožičenja veliko prednosti. Arbitrary Angle wiring has many advantages. Prvič, če ne uporabljate kotov med segmentnimi črtami, prihranite prostor na PCB -ju (poligoni vedno zavzamejo več prostora kot tangente). Traditional automatic cablers can place only three wires between adjacent components (see left and center in Figure 3). Vendar pa pri ožičenju pod katerim koli kotom obstaja dovolj prostora za polaganje 4 žic na isto pot, ne da bi kršili preverjanje pravil oblikovanja (DRC). Recimo, da imamo čip v pozitivnem načinu in želimo priključke čipa priključiti na dva druga zatiča. Using only 90 degrees takes up a lot of space. Uporaba poljubnega kotnega ožičenja lahko skrajša razdaljo med čipom in drugimi zatiči, hkrati pa zmanjša odtis. In this case, the area was reduced from 30 square centimeters to 23 square centimeters. Vrtenje čipa pod katerim koli kotom lahko prinese tudi boljše rezultate. 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. To ni le teorija, ampak tudi praktična rešitev (včasih edina možna rešitev). Shows an example of a simple PCB. Rezultati topologije kabla, medtem ko so rezultati samodejnega kabla na podlagi optimalne oblike fotografije dejanskega tiskanega vezja. An automatic cabler based on optimal shape cannot do this because the components are rotated at arbitrary angles. Potrebujete več prostora in če ne obračate komponent, morate napravo povečati. 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. Če med žičnimi segmenti obstaja kot, se bo stopnja preslušavanja zmanjšala, ko se bo ta kot povečal. 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. Razmislite o naslednjih treh načinih ožičenja. 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. Kabel samodejno izračuna optimalno obliko žice (ob upoštevanju potrebne varnostne razdalje). Prilagodljivo ožičenje lahko torej močno skrajša čas, potreben za urejanje topologije, kar lepo podpira večkratno ponovno kabliranje, da se zadovoljijo omejitve. To prikazuje zasnovo tiskanega vezja, ki se premika skozi luknje in veje. Med samodejnim premikanjem se točke vej žice in luknje prilagodijo optimalnemu položaju. 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. Ko je pot najdena, je fiksna in postane del labirinta. Pomanjkljivost zaporednega ožičenja je, da je lahko rezultat ožičenja odvisen od vrstnega reda ožičenja. Ko topološka kakovost še zdaleč ni popolna, se problem “zatikanja” pojavi na lokalno majhnih območjih. 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. Upogibanje žice se nanaša na pojav, da mora žica v enem omrežju za dostop do predmeta hoditi okoli predmeta v drugem omrežju. Rewiring a wire will not correct this. Prikazan je primer upogibanja. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Prikažejo se rezultati samodejne obdelave. 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. Rdeče upognjene žice so označene. V Steinerjevem drevesu morajo biti vse vrstice povezane kot odseki z oglišči (končne točke in dodatki). Na vrhu vsakega novega oglišča se morajo zbližati trije segmenti in končati se morajo največ trije segmenti. The Angle between the line segments that converge to the vertex shall not be less than 120 degrees. Zgraditi Steinerja s temi zadostnimi pogojnimi lastnostmi ni zelo težko, ni pa nujno, da je minimalen. Gray Steiner trees are not optimal, but black Steiner trees are. Pri oblikovanju praktičnega komuniciranja je treba upoštevati različne vrste ovir. Omejujejo zmožnost gradnje minimalnih razsežnih dreves z uporabo algoritmov in Steinerjevih dreves z uporabo geometrijskih metod. 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. Glavni mehanizem tukaj je algoritem, ki temelji na silah, ki izračuna sile, ki delujejo na nova oglišča, in jih večkrat premakne v ravnovesno točko (velikost in smer sil sta odvisni od žic na sosednjih vejah). Če je kot med parom odsekov črt, povezanih z ogliščem (končnico ali seštevkom), manjši od 120 stopinj, lahko dodamo točko razvejanja, nato pa lahko uporabimo mehanski algoritem za optimizacijo položaja teme. 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. Omogoča tudi območja, kjer so povezave s končnimi točkami prepovedane, število vozlišč končnih točk pa je lahko poljubno.

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. Nekaterim slojem na diagramu je ušlo ožičenje. Slika 16 prikazuje četrtino BGA. Hkrati se pri uporabi ožičenja “center to periferija” število kanalov, potrebnih za izhod na obrobje, ne spreminja od plasti do plasti. To bo močno zmanjšalo število plasti. Za komponente 28×28 mm zadostuje 7 slojev. Za večje komponente je to 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. To lahko izvede topološki avtomatski kabel s poljubnim kotom. 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.