The layout is plain to put devices on the board. At this time, if the preparations mentioned earlier are done, you can generate a network table (design- "Create Network on the schematic diagram, and then introduce the network table (Design-" Load Nets on the PCB diagram. I saw the device piled up all the time, and there were flying lines between the feet. Then you can lay the device layout. The general layout is performed as follows:

1. Reasonable partition according to electrical performance, generally divided into: digital circuit region (that is, fear of interference, and interference), analog circuit area (afraid of interference), power -driven area (interference source);

2. To complete the same function circuit, you should try to get closer as possible, and adjust the components to ensure the most concise connection; at the same time, adjust the relative position between each function block to make the connection between the function block the most concise;

3. For high -quality components, the installation location and installation intensity should be considered; the heating elements should be separated from the temperature sensitive components, and the heat -to -flow measures should be considered if necessary;

4.I/O driver device should be as close to the edge of the printing board as possible, and close the plug -in;

5. Clock generator (such as: crystal or clock vibration) should be closer to the device that uses the clock as much as possible;

6. Between the power input foot and ground of each integrated circuit, a decoupling capacitor needs to be added (generally a monolithic capacitor with high frequency performance); when the circuit board space is dense, you can also be around several integrated circuits around several integrated circuits. Add a 容 capacitor.

7. Put the diode at the relay coil (1N4148);

8. The layout requirements should be balanced, dense and orderly, and cannot be light or sinked with heads and feet -need special attention. When placing components, be sure to consider the actual size of the component (the area and height of the area), between the components, and the components The relative position to ensure the electrical performance of the circuit board and the feasibility and convenience of production and installation. At the same time, it should be properly modified to the above principles. Swing neat and consistent direction, we cannot put "staggered".