1. If the PCB has a large amount of ground, such as SGND, AGND, GND, etc., it is necessary to use the most important "ground" as the reference for independent copper coating based on the different positions of the PCB surface. Separate the digital and analog power lines for copper coating, and before copper coating, thicken the corresponding power lines: 5.0V, 3.3V, etc.

2. For single point connections to different locations, the method is to connect through a 0 ohm resistor, magnetic bead, or inductor.

3. The crystal oscillator in the circuit is a high-frequency emission source. For the copper coating near the crystal oscillator, the method is to surround the crystal oscillator with copper coating, and then ground the outer shell of the crystal oscillator separately.

4. If the problem of islands (dead zones) is significant, then define a place and add it through a hole.

5. When starting wiring, the ground wire should be treated equally. When wiring, the ground wire should be properly routed and no through holes should be added to increase the ground pin.

6. It is best not to have sharp corners on the board (<=180 degrees), as from an electromagnetic perspective, this constitutes a transmitting antenna! It is recommended to use the edges along the arc.

7. Open areas for wiring in the middle layer of multi-layer boards should not be covered with copper.

8. The metal inside the equipment, such as metal radiators, metal reinforcement strips, etc., must be well grounded.

9. The heat dissipation metal block of the three terminal voltage regulator must be well grounded; The grounding isolation strip near the crystal oscillator must be well grounded.