PCB wiring methods continue to improve, and flexible wiring techniques can reduce wire length and free up more PCB space. Pengkabelan PCB konvensional dibatasi oleh koordinat kabel tetap dan tidak adanya kabel bersudut sewenang-wenang. Menghapus batasan ini dapat secara signifikan meningkatkan kualitas kabel.

Let’s start with some terminology. Kami mendefinisikan pengkabelan Sudut sewenang-wenang sebagai pengkabelan kawat menggunakan segmen dan radian Sudut sewenang-wenang. Ini adalah jenis kabel kawat, tetapi tidak terbatas pada hanya menggunakan segmen garis sudut 90 derajat dan 45 derajat. 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. Mari kita definisikan istilah kabel fleksibel sebagai kabel kawat tanpa bentuk tetap yang memungkinkan penghitungan ulang bentuk kawat secara real-time untuk mencapai kemungkinan transformasi berikut. Hanya busur dari rintangan dan garis singgung bersamanya yang digunakan untuk membentuk bentuk garis. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Kabel hijau dan merah berjalan pada lapisan yang berbeda dari 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. Gambar 1B adalah model PCB menggunakan busur dan sudut arbitrer. 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. Menunjukkan PCB asli yang dikembangkan pada tahun 1972 oleh perusahaan Amerika bernama Digibarn untuk pengkabelan tangan lengkap. This is a PCB board based on Intel8008 computer. Pengkabelan Sudut sewenang-wenang yang ditunjukkan pada Gambar 2 sebenarnya serupa. Why would they use arbitrary Angle wiring? Karena jenis kabel ini memiliki banyak kelebihan. 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). Namun, saat memasang kabel di setiap Sudut, ada cukup ruang untuk meletakkan 4 kabel di jalur yang sama tanpa melanggar pemeriksaan aturan desain (DRC). Misalkan kita memiliki chip mode positif dan ingin menghubungkan pin chip ke dua pin lainnya. Using only 90 degrees takes up a lot of space. Menggunakan kabel Sudut sewenang-wenang dapat memperpendek jarak antara chip dan pin lainnya, sekaligus mengurangi jejak. 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. Ini bukan hanya teori, tetapi juga solusi praktis (terkadang satu-satunya solusi yang mungkin). 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. Anda membutuhkan lebih banyak area, dan jika Anda tidak memutar komponen, perangkat harus dibuat lebih besar. 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. Jika ada Sudut antara segmen kawat, maka saat Sudut ini meningkat, tingkat crosstalk akan berkurang. 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. Cabler secara otomatis menghitung bentuk kabel yang optimal (dengan mempertimbangkan jarak aman yang diperlukan). Flexible cabling can therefore greatly reduce the time required to edit the topology, nicely supporting multiple recabling to meet constraints. Ini menunjukkan desain PCB yang bergerak melalui lubang dan titik cabang. 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. Ketika jalan ditemukan, itu diperbaiki dan menjadi bagian dari labirin. Kerugian dari pengkabelan sekuensial adalah bahwa hasil pengkabelan mungkin bergantung pada urutan pengkabelan. Ketika kualitas topologi masih jauh dari sempurna, masalah “terjebak” terjadi di area kecil lokal. 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. Pembengkokan kawat mengacu pada fenomena bahwa kawat dalam satu jaringan harus berjalan di sekitar objek di jaringan lain untuk mengakses suatu objek. Rewiring a wire will not correct this. Contoh pembengkokan ditunjukkan. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Hasil pemrosesan otomatis ditampilkan. 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. Kabel bengkok merah disorot. Dalam pohon Steiner, semua garis harus dihubungkan sebagai segmen ke simpul (titik akhir dan tambahan). Di bagian atas setiap simpul baru, tiga segmen harus bertemu dan tidak lebih dari tiga segmen harus berakhir. 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. Dalam desain komunikasi praktis, berbagai jenis hambatan harus dipertimbangkan. Mereka membatasi kemampuan untuk membangun pohon merentang minimum menggunakan kedua algoritma dan pohon Steiner menggunakan metode geometris. 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. Mekanisme utama di sini adalah algoritma berbasis gaya yang menghitung gaya yang bekerja pada simpul baru dan berulang kali memindahkannya ke titik keseimbangan (besar dan arah gaya bergantung pada kabel pada titik cabang yang berdekatan). Jika Sudut antara sepasang segmen garis yang terhubung ke titik (terminal atau tambahan) kurang dari 120 derajat, titik cabang dapat ditambahkan, dan kemudian algoritma mekanik dapat digunakan untuk mengoptimalkan posisi titik. 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. Ini juga memungkinkan untuk area di mana koneksi titik akhir dilarang, dan jumlah node titik akhir dapat berubah-ubah.

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. Gambar 16 menunjukkan seperempat dari 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. Ini akan sangat mengurangi jumlah lapisan. For a component size of 28x28mm, 7 layers are sufficient. Untuk komponen yang lebih besar, ini adalah 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. Kabel otomatis topologi sudut sewenang-wenang dapat melakukan ini. 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.