ICL and PDL are both related to testing and instrumentation within integrated circuits, but they serve different purposes. ICL (Instrument Connectivity Language) describes scan paths, while PDL (Procedural Description Language) defines an instrument's operations and functions.
Here's a breakdown of their differences:
Key Differences Between ICL and PDL
| Feature | ICL (Instrument Connectivity Language) | PDL (Procedural Description Language) |
|---|---|---|
| Purpose | Describes the scan paths within a circuit. | Defines the instrument's operations and functions. |
| Scope | Focuses on how instruments are connected for data access. | Focuses on the actions, sequences, and test procedures of the instruments. |
| Output | Path description; outlines connections and data flow. | Test vectors and documentation on instrument actions. |
| Usage | Used to specify and configure how data travels through the embedded instruments. | Used to dictate the function and expected behavior of each instrument. |
| Relation to IJTAG | Describes the scan paths used by IEEE P1687 IJTAG instruments. | Used to document the actions of IEEE P1687 IJTAG instruments. |
Further Explanation
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ICL (Instrument Connectivity Language): Think of ICL as the map for accessing embedded instruments within a chip. It tells the testing system how to move data to and from these instruments using scan paths. According to the provided reference, "ICL is used to describe each of these scan paths." Without a proper ICL description, the test system wouldn’t know how to communicate with, and test embedded instruments.
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PDL (Procedural Description Language): PDL is like the instruction manual for the embedded instruments. It defines what each instrument does, how it's used, and the sequence of operations for testing. The provided reference states, "PDL defines the instrument's operations and functions and it is eventually turned into test vectors... In addition, PDL will document each instrument's actions and sequences." PDL is what turns the theoretical description of an instrument into practical testing methods. It's the basis for generating test vectors.
Practical Example
Imagine you have a complex machine (the chip).
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ICL would be like the schematics of all the internal pathways and connections that allow access to specific testing points.
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PDL would be the detailed step-by-step instructions on how to test each individual part of the machine using those access points, including what results to expect.
Key Takeaways:
- ICL and PDL work together in the testing and verification of embedded instruments.
- ICL provides the necessary connectivity while PDL defines the operations.
- Both are essential for effectively testing modern complex integrated circuits.
