PCB Mitohy manatsara ny fomba fitifirana, ary ny teknikan’ny tariby malefaka dia afaka mampihena ny halavan’ny tariby sy manafaka toerana bebe kokoa PCB. Ny tariby PCB mahazatra dia voafetra amin’ny kofehin-tariby raikitra sy ny tsy fisian’ny tariby misy zoro arbitrary. Ny fanesorana ireo fetra ireo dia afaka manatsara ny kalitaon’ny tariby.

Let’s start with some terminology. Izahay dia mamaritra ny tariby Angle tsy ara-dalàna ho toy ny tariby tariby amin’ny alàlan’ny fizarana sy ny radiana an-tendrony. Izy io dia karazana tariby tariby, saingy tsy voafetra amin’ny fampiasana segondra 90 degre sy 45 degree Angle fotsiny. 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. Andao hofaritana ny teny hoe fantsom-pifandraisana mora azo tariby toy ny tariby tariby tsy misy endrika raikitra izay mamela ny famerenana amin’ny laoniny tariby tena izy mba hahatratrarana ireto fiovana manaraka ireto. Ny arcs avy amin’ny sakana sy ny tangents iraisana no ampiasaina hanefena ny endrika tsipika. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Ny tariby maitso sy mena dia mihazakazaka amin’ny sosona samihafa amin’ny maodely 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. Ny sary 1B dia maodely PCB mampiasa arcs sy zoro arbitrary. 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. Mampiseho tena PCB novolavolaina tamin’ny taona 1972 nataon’ny orinasa amerikana antsoina hoe Digibarn ho an’ny tariby tariby feno. This is a PCB board based on Intel8008 computer. Ny tariby Angle tsy ara-dalàna aseho amin’ny sary 2 dia tena mitovy. Why would they use arbitrary Angle wiring? Satria ity karazana tariby ity dia manana tombony maro. Arbitrary Angle wiring has many advantages. Voalohany, ny tsy fampiasana ny zoro eo anelanelan’ny tsipika dia mitahiry ny habaka PCB (ny polygons dia mitaky habaka bebe kokoa noho ny tangents). Traditional automatic cablers can place only three wires between adjacent components (see left and center in Figure 3). Na izany aza, rehefa mandeha tariby amin’ny zoro rehetra, misy toerana ampy hametrahana tariby 4 amin’ny lalana iray ihany nefa tsy mandika ny fitsipiky ny famolavolana fitsipika (DRC). Eritrereto hoe manana chip maody miabo isika ary te hampifandray ireo paingotra amina pin hafa roa. Using only 90 degrees takes up a lot of space. Ny fampiasana tariby Angle tsy ara-dalàna dia afaka hanafohezana ny elanelana misy eo anelanelan’ny puce sy ny tsimatra hafa, sady mampihena ny dian-tongotra. 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. Tsy teôria fotsiny io, fa vahaolana azo ampiharina (indraindray ihany no vahaolana tokana). Shows an example of a simple PCB. Valin’ny topology cabler, raha ny valin’ny cabler mandeha ho azy miorina amin’ny endrika tsara indrindra dia sarin’ny PCB tena izy. An automatic cabler based on optimal shape cannot do this because the components are rotated at arbitrary angles. Mila faritra bebe kokoa ianao, ary raha tsy ahodinao ireo singa, dia tokony hihoatra ny fitaovana. 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. Raha misy Angle eo anelanelan’ny fizarana tariby dia rehefa mihabetsaka ity Angle ity dia hihena ny haavon’ny crosstalk. 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. Diniho ireto fomba telo manaraka ireto. 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. Ny cabler dia manisa avy hatrany ny endrika tariby tariby (mihevitra ny fahazoan-dàlana fiarovana ilaina). Ny cabling malefaka dia afaka mampihena be ny fotoana takiana amin’ny fanitsiana ny topolojia, manohana tsara ny famerenana maro hihaona amin’ny teritery. Ity dia mampiseho famolavolana PCB izay mamakivaky ny lavaka sy ny tebon’ny sampana. Mandritra ny hetsika mandeha ho azy, ny teboka misy ny sampana tariby sy ny lavaka dia ahitsy amin’ny toerana mety indrindra. 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. Rehefa hita ny làlana iray dia raikitra ary lasa ampahany amin’ilay maze. Ny fatiantoka ny filaharana mifandimby dia ny valin’ny tariby dia mety miankina amin’ny filaharana mifehy. Raha mbola tsy lavorary ny kalitao topolojika, ny olana “mihitsoka” dia miseho amin’ny faritra kely eo an-toerana. 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. Ny famolahana tariby dia manondro ny trangan-javatra misy tariby amin’ny tambajotra iray dia tsy maintsy mandeha manodidina ny zavatra amin’ny tambajotra hafa mba hidirana amin’ny zavatra iray. Rewiring a wire will not correct this. Ohatra iray amin’ny hiondrika no aseho. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Aseho ny valin’ny fikarakarana mandeha ho azy. 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. Misongadina ny tariby mena miforitra. Ao amin’ny hazo Steiner, ny tsipika rehetra dia tsy maintsy ampifandraisina ho toy ny fizarana amin’ny tampon (teboka farany sy fanampiana). Eo an-tampon’ny tampon’ny vertex vaovao dia misy fizarana telo tsy maintsy mihodina ary tsy mihoatra ny telo ny fizarana tokony hifarana. The Angle between the line segments that converge to the vertex shall not be less than 120 degrees. Tsy dia sarotra loatra ny manamboatra Steiner miaraka amin’ireto toetra misy fepetra ireto, fa tsy voatery ho kely. Gray Steiner trees are not optimal, but black Steiner trees are. Amin’ny famolavolana fifandraisana azo ampiharina dia tsy maintsy dinihina ny karazana sakana samihafa. Mametra ny fahafaha-manamboatra hazo farafahakeliny farafahakeliny izy ireo amin’ny alàlan’ny algorithma sy ny hazo Steiner amin’ny alàlan’ny fomba geometrika. 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. Ny rafitra lehibe eto dia ny algorithm mifototra amin’ny hery izay manisa ny hery miasa amin’ny tampon-tampony vaovao ary mamindra azy ireo hatrany amin’ny teboka mandanjalanja (miankina amin’ny tariby amin’ireo teboka mifanila aminy ny habeny sy ny fitarihan’ny herin’ny hery). Raha ny Angle eo anelanelan’ny tsanganana tsipika mifandraika amin’ny vertex (terminus na fanampiana) dia latsaky ny 120 degre, dia azo ampiana teboka iray ny sampana, ary avy eo ny algorithm mekanika dia azo ampiasaina hanatsarana ny toerana tampon’ny 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. Izy io koa dia mamela ireo faritra izay voarara ny fifandraisana endpoint, ary ny isan’ny teboka fiafarana dia mety ho tsy ara-dalàna.

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. Mampiseho ny ampahefatry ny BGA ny sary 16. Mandritra izany fotoana izany, rehefa mampiasa ny fomba fitifirana “centre par perhery”, ny isan’ny fantsona takiana mba hivoahana amin’ny sisin-tany dia tsy miova amin’ny sosona iray. Io dia hampihena be ny isan’ny sosona. Ho an’ny haben’ny singa 28x28mm, sosona 7 dia ampy. Ho an’ireo singa lehibe kokoa, fandresena azo. 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. Mahavita manao izany ny cabler automatique topical arbitrary zoro. 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.