PCB design flow
PCB rule setting
Units designed to follow the rules set unit properties in the canvas, where the unit is mil. 10mil minimum conductor width; minimum spacing between different network elements 8mil; 24mil outer diameter of the hole, the hole inside diameter 12mil; line length is not provided; in the PCB design process, to be turned "real time detection rule", " distance detecting elements to the copper "and" displayed in the wiring DRC safety margin "function.
Layout principles
Layout generally comply with the following principles:
(1) Principle shortest wiring. For example, an integrated circuit (IC) of the decoupling capacitors should be placed in the corresponding VCC and GND
Between the pins and the distance between the IC as close as possible, so that the loop is formed between VCC and GND shortest.
(2) the same function block is a collection principles. Related i.e. to achieve the same functional circuit modules in the component concentration distribution near
Bureau.
(3) comply with the "small big after the first, after the difficult easy first" principle, that is an important element circuit, core components should be given priority layout.
(4) with reference to the schematic layout should, according to the main flow direction arrangement rule of the main components of the signal circuit.
(5) to facilitate the arrangement of components of the commissioning and maintenance, i.e., small components can not be placed around the large components, need to have enough space around debugging components.
(6) the same type of plug-in components should be placed in one direction in the X or Y direction. The same type of polar discrete components should be kept consistent in X or Y direction, to facilitate the production and testing.
(7) layout, the edge of the circuit board components, from the edge of the board is generally not less than 2mm, if space permits, it is recommended to maintain the distance at 5mm.
(8) Crystal layout, the IC should be as close as possible, and the capacitance of the crystal oscillator connected to close.
Layout Considerations
Wiring should note the following:
(1) to the power supply mains bold principle (in particular the power input board / output lines).
(2) PCB routing and not too close to the positioning hole of the circuit board frame, or when the PCB during drilling, a portion of the wire can easily be cut off even.
(3) prohibits the same layer as the wiring 90 ° corners, but via a wiring 90 ° between the different layers is permissible. Further, compliance with the horizontal wiring layer as wiring, take another vertical line principle.
(4) high-frequency signal line, such as a crystal oscillation circuit STM32 core wiring board, not bold, the proposed design according to 10mil width, and in the same layer as the wiring.
Video learning materials:
PADS-PCB原图绘制
http://www.makeru.com.cn/live/4006_1430.html?s=45051
PCB电路设计之PADS_LOGIC原理图设计
http://www.makeru.com.cn/live/1758_1053.html?s=45051
PCB电路设计之PADS_LAYOUT原理图设计
http://www.makeru.com.cn/live/1758_1072.html?s=45051
PCB电路设计之STM32开发板设计
http://www.makeru.com.cn/live/1758_1105.html?s=45051
老司机倾囊相授-PCB大牛修炼秘籍
http://www.makeru.com.cn/live/3472_1296.html?s=45051
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