1, If the designed circuit system contains FPGA devices, the pin assignments must be verified using the Quartus II software before drawing the schematic. (Some special pins in the FPGA can not be used as normal IO).

2, 4-layer pcb board from top to bottom are: signal plane layer, ground, power, signal plane layer; 6 layers from top to bottom are: signal plane layer, ground, signal internal layer, Power supply, signal plane layer. 6 layers above the board (the advantage is: anti-interference radiation), give priority to select the inner layer traces, can not get away from the choice of plane layer, to prohibit the ground from the ground or power line (reason: will split the power layer, resulting in parasitic effects).

3, multi-power system wiring: FPGA + DSP system to do 6-layer board, generally at least 3.3V + 1.2V + 1.8V +5 V.
3.3V is generally the main power supply, directly shop the power layer, through the hole is easy to release the global power network;
5V may be the power input, only in a small area of ​​copper shop. And as thick as possible
1.2V and 1.8V are core power (if the direct use of the line will be faced in the BGA device encountered great difficulties), the layout as much as possible to 1.2V and 1.8V separately, and 1.2V or 1.8V connected The components are arranged in a compact area and are connected using copper.
In short, because the power network throughout the PCB, if the use of the way the line will be very complicated and will be very far away, the use of copper method is a good choice!

4, between the adjacent lines using cross-way: both parallel wires can reduce the electromagnetic interference between, and easy to track.

5, the analog number to be isolated, how to isolate the layout of the device used for analog signal and digital signal devices separately, and then from the middle of the AD chip across the board!
Analog signal shop analog ground, analog ground / analog power supply and digital power supply through the inductive / magnetic single point connection.

6, PCB design software based on the PCB design can also be seen as a software development process, software engineering, the most focus on "iterative development" thinking, reduce the probability of PCB errors.
(1) schematic inspection, with particular attention to the device power and ground (power and the system is the blood of the system, can not have the slightest negligence);
(2) PCB packaging rendering (to confirm the schematic diagram of the pin is wrong);
(3) PCB packaging size confirmed one by one, add a verification label, add to the design package library;
(4) into the netlist, while adjusting the edge of the layout of the signal sequence (after the layout can no longer use OrCAD's automatic component function);
(5) manual wiring (edge ​​cloth edge check the power to the network, said earlier: the power network using copper way, so less with the alignment);
In short, the guiding ideology in PCB design is to draw the layout of the package layout and routing feedback (from the correctness of the signal connection, the convenience of signal routing considerations).

7, crystal from the chip as close as possible, and the crystal as far as possible without alignment, paving the network copper. Use multiple clocks using a tree clock tree.

8, the arrangement of the signal on the connector on the difficulty of the greater degree of wiring, so the edge of the wiring to adjust the schematic on the signal (but do not re-symbolize the components).

9, multi-board connector design:
(1) the use of cable connection: the same interface up and down;
(2) straight socket: upper and lower interface mirror symmetry, as shown below:

10, the module connection signal design:
(1) If the two modules placed on the same side of the PCB, the discipline number is large then large (mirror connection signal);
(2) If the two modules on the PCB in different faces, the discipline number is small and then large.
Doing so can place the signal as if it were on the right as above. Of course, the above method is not a rule, I always say, everything on demand and change (this can only own comprehend), but in many cases in this way design is very useful.

11, the power of the loop design:
The power supply area on the map area is large, susceptible to electromagnetic interference.
The figure above is improved - the power supply is close to the ground line, reducing the area of ​​the circuit and reducing the electromagnetic interference (679 / 12.8, about 54 times). Therefore, the power and ground should be close to the alignment! And between the signal lines should try to avoid parallel alignment, reduce the mutual inductance between the signal effect.