How can you design digital circuits for easy debugging and diagnosis?

1 Use modular and hierarchical design

One of the best ways to simplify your digital circuit design is to use modular and hierarchical design. This means that you divide your circuit into smaller and independent modules that perform specific functions, and then connect them in a hierarchical structure that reflects the overall logic and behavior of the system. Modular and hierarchical design allows you to isolate and test each module separately, and to reuse and modify them as needed. It also helps you to avoid errors and conflicts that may arise from overlapping or redundant signals and components.

2 Incorporate test points and probes

Another way to make your digital circuit design easier to debug and diagnose is to incorporate test points and probes. Test points are locations on the circuit board or the chip where you can access and measure the signals or voltages of interest. Probes are devices that connect to the test points and provide the output to a display or a recorder. Test points and probes enable you to monitor and analyze the performance and behavior of your circuit under different conditions and inputs. They also help you to identify and locate faults and anomalies that may affect the functionality or reliability of your circuit.

3 Use design for testability methods

Design for testability (DFT) is a set of methods and techniques that aim to improve the testability and quality of digital circuits. To achieve this, DFT adds extra hardware or software features that facilitate testing, verification, and diagnosis. Scan design inserts scan chains into the circuit that allow you to control and observe the internal states. Built-in self-test embeds test generators and test analyzers into the circuit to perform self-testing and self-diagnosis. Boundary scan uses a special type of scan chain that connects the boundary pins of the circuit to the internal logic, enabling you to test interconnections between the circuit and other devices or components, as well as its functionality. Utilizing these methods can reduce the need for external test equipment, increase speed and efficiency of testing, and ultimately improve the quality of digital circuits.

4 Apply coding standards and conventions

Coding standards and conventions are important rules and guidelines that should be applied to digital circuit design to make the code easier to read, understand, and debug. To do this, you should use meaningful and consistent names for variables, signals, modules, and functions. Additionally, comments and documentation should be used to explain the purpose and logic of the code. Indentation, spacing, and alignment are also important for organizing and structuring the code. Consistent and appropriate data types, operators, and expressions should also be used. Furthermore, hard-coded values, magic numbers, and literals should be avoided, as well as using a modular and hierarchical code structure that matches your circuit design.