In the Microprocessor Circuit Board Cloning, there are many types of ground wires, such as system ground, shield ground, logic ground, analog ground, etc. Whether the ground wire is properly layout will determine the anti-interference ability of the circuit board reverse engineering.
In the Microprocessor Circuit Board Cloning, there are many types of ground wires, such as system ground, shield ground, logic ground, analog ground, etc. Whether the ground wire is properly layout will determine the anti-interference ability of the circuit board reverse engineering
When designing ground wires and ground points, the following issues should be considered:
The logic ground and the analog ground should be wired separately and cannot be used together.
Connect their respective ground wires to the corresponding power ground wires. When cloning Microprocessor Circuit Board, the analog ground wire should be as thick as possible, and the grounding area of the terminal should be enlarged as much as possible.
Generally speaking, for the input and output analog signals, it is best to isolate them from the single-chip microcomputer circuit through optocouplers. When cloning the micro-controller printed circuit board of the logic circuit, the ground wire should form a closed-loop form to improve the anti-interference ability of the circuit.
The ground wire should be as thick as possible. If the ground wire is very thin, the resistance of the ground wire will be large, causing the ground potential to change with the change of the current, resulting in unstable signal level, resulting in a decrease in the anti-interference ability of the circuit.
When cloning the micro-controller printed circuit board of the logic circuit, the ground wire should form a closed-loop form to improve the anti-interference ability of the circuit
When the wiring space allows, ensure that the width of the main ground wire is at least 2-3mm, and the ground wire on the component pins should be about 1.5mm. Pay attention to the choice of grounding point. When the signal frequency on the circuit board is lower than 1MHz, since the electromagnetic induction between the wiring and the components has little influence, and the circulating current formed by the grounding circuit has a greater influence on the interference, it is necessary to use a little grounding so that it does not form a loop.
When the signal frequency on the circuit board is higher than 10MHz, due to the obvious inductance effect of the PCB layout design, the impedance of the ground wire becomes very large, and the circulating current formed by the ground circuit is no longer the main problem. Therefore, multi-point grounding should be used to reduce the ground wire impedance as much as possible.
