PCB wiring methods continue to improve, and flexible wiring techniques can reduce wire length and free up more PCB space. Mae gwifrau PCB confensiynol wedi’i gyfyngu gan gyfesurynnau gwifren sefydlog a diffyg gwifrau ongl fympwyol. Gall dileu’r cyfyngiadau hyn wella ansawdd y gwifrau yn sylweddol.

Let’s start with some terminology. Rydym yn diffinio gwifrau Angle mympwyol fel gwifrau gwifren gan ddefnyddio segmentau Angle mympwyol a radianau. Mae’n fath o weirio gwifren, ond nid yw’n gyfyngedig i ddefnyddio segmentau llinell Angle 90 gradd a 45 gradd yn unig. 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. Gadewch inni ddiffinio’r term gwifrau hyblyg fel gwifrau gwifren heb siâp sefydlog sy’n galluogi ailgyfrifo siâp gwifren amser real i gyflawni’r posibiliadau trawsnewid canlynol. Dim ond arcs o rwystrau a’u tangiadau cyffredin sy’n cael eu defnyddio i ffurfio siâp y llinell. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Mae’r gwifrau gwyrdd a choch yn rhedeg ar wahanol haenau o’r model 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. Mae Ffigur 1B yn fodel PCB sy’n defnyddio arcs ac onglau mympwyol. 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. Yn dangos PCB go iawn a ddatblygwyd ym 1972 gan gwmni Americanaidd o’r enw Digibarn ar gyfer gwifrau llaw cyflawn. This is a PCB board based on Intel8008 computer. Mae’r gwifrau Angle mympwyol a ddangosir yn Ffigur 2 yn debyg mewn gwirionedd. Why would they use arbitrary Angle wiring? Oherwydd bod gan y math hwn o weirio lawer o fanteision. Arbitrary Angle wiring has many advantages. First, not using the angles between line segments saves PCB space (polygons always take up more space than tangents). Traditional automatic cablers can place only three wires between adjacent components (see left and center in Figure 3). Fodd bynnag, wrth weirio ar unrhyw Angle, mae digon o le i osod 4 gwifren ar yr un llwybr heb fynd yn groes i wirio rheolau dylunio (DRC). Tybiwch fod gennym sglodyn modd positif ac eisiau cysylltu’r pinnau sglodion â dau binn arall. Using only 90 degrees takes up a lot of space. Gall defnyddio gwifrau ongl mympwyol fyrhau’r pellter rhwng y sglodyn a phinnau eraill, gan leihau’r ôl troed. In this case, the area was reduced from 30 square centimeters to 23 square centimeters. Rotating the chip at any Angle can also provide better results. 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. Mae hon nid yn unig yn theori, ond hefyd yn ateb ymarferol (weithiau’r unig ateb posibl). Shows an example of a simple PCB. Topology cabler results, while automatic cabler results based on optimal shape are photos of the actual PCB. An automatic cabler based on optimal shape cannot do this because the components are rotated at arbitrary angles. Mae angen mwy o arwynebedd arnoch chi, ac os na fyddwch chi’n cylchdroi’r cydrannau, mae’n rhaid gwneud y ddyfais yn fwy. 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. Os oes Angle rhwng y segmentau gwifren, yna wrth i’r Angle hwn gynyddu, bydd lefel y crosstalk yn gostwng. 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. Consider the following three wiring methods. 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. Mae’r ceblwr yn cyfrifo siâp gorau’r wifren yn awtomatig (gan ystyried y cliriad diogelwch angenrheidiol). Flexible cabling can therefore greatly reduce the time required to edit the topology, nicely supporting multiple recabling to meet constraints. Mae hyn yn dangos dyluniad PCB sy’n symud trwy dyllau a phwyntiau cangen. During automatic movement, wire branch points and through-holes are adjusted to the optimal position. 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. Pan ddarganfyddir llwybr, mae’n sefydlog ac yn dod yn rhan o’r ddrysfa. Anfantais gwifrau dilyniannol yw y gall canlyniad y gwifrau ddibynnu ar y gorchymyn gwifrau. Pan fydd ansawdd topolegol yn dal i fod ymhell o fod yn berffaith, mae’r broblem o “fynd yn sownd” yn digwydd mewn ardaloedd bach lleol. 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. Mae plygu gwifren yn cyfeirio at y ffenomen bod yn rhaid i wifren mewn un rhwydwaith gerdded o amgylch gwrthrych ar rwydwaith arall i gael mynediad at wrthrych. Rewiring a wire will not correct this. Dangosir enghraifft o blygu. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Arddangosir canlyniadau prosesu awtomatig. 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. Amlygir gwifrau plygu coch. Mewn coeden Steiner, rhaid cysylltu pob llinell fel segmentau â fertigau (endpoints ac ychwanegiadau). Ar ben pob fertig newydd, rhaid i dri segment gydgyfeirio a rhaid i ddim mwy na thair segment ddod i ben. The Angle between the line segments that converge to the vertex shall not be less than 120 degrees. It is not very difficult to construct a Steiner with these sufficient conditional properties, but it is not necessarily minimal. Gray Steiner trees are not optimal, but black Steiner trees are. Wrth ddylunio cyfathrebu ymarferol, rhaid ystyried gwahanol fathau o rwystrau. Maent yn cyfyngu ar y gallu i adeiladu coed rhychwantu lleiaf gan ddefnyddio algorithmau a choed Steiner gan ddefnyddio dulliau geometrig. 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. Y prif fecanwaith yma yw algorithm sy’n seiliedig ar heddluoedd sy’n cyfrifo’r grymoedd sy’n gweithredu ar y fertigau newydd ac yn eu symud dro ar ôl tro i bwynt ecwilibriwm (mae maint a chyfeiriad y grymoedd yn dibynnu ar y gwifrau yn y pwyntiau cangen cyfagos). Os yw’r Angle rhwng pâr o segmentau llinell sy’n gysylltiedig â fertig (terfynfa neu ychwanegiad) yn llai na 120 gradd, gellir ychwanegu pwynt cangen, ac yna gellir defnyddio algorithm mecanyddol i wneud y gorau o safle’r fertig. 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. Mae hefyd yn caniatáu ar gyfer ardaloedd lle mae cysylltiadau endpoint wedi’u gwahardd, a gall nifer y nodau endpoint fod yn fympwyol.

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. Some of the layers in the diagram have escaped wiring. Mae Ffigur 16 yn dangos chwarter BGA. At the same time, when using the “center to periphery” wiring method, the number of channels required to exit to the periphery does not change from layer to layer. Bydd hyn yn lleihau nifer yr haenau yn fawr. Ar gyfer maint cydran o 28x28mm, mae 7 haen yn ddigonol. Ar gyfer cydrannau mwy, mae’n ennill-ennill. 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. Gall ceblwr awtomatig topolegol Angle Mympwyol wneud hyn. 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.