This standard formalizes how to describe, in a way that extends IEEE 1687 ICL and PDL, retargetable access circuitry within an IC relevant to testing analog functions of the IC. The description is also relevant to insertion of such test access circuitry, to generation of tests using this access circuitry, and automating these tasks. Analog test access includes access to analog and digital signals; analog test control includes control of circuits under test (CUTs), control of test instruments within the IC, and control of the access paths between CUTs and test instruments, the latter including on- and off-chip instruments. The access may be aimed at, but not limited to, testing for manufacturing defects, measuring, deciding pass/fail, trimming, or binning an IC, or may be for in-field testing to indicate failure to a higher-level function, activate redundant circuitry, indicate impending failure, etc.
In this context, "retargetable" access circuitry means circuitry that is automatically re-configurable without significantly affecting its performance, and an "analog" function means a function that has input, internal, or output signals with meaningful values in a defined continuous range, and the function has at least one non-deterministic performance parameter that has upper and/or lower test limits (the limits may be real numbers or quantized digital equivalents). An analog instrument is one that measures analog properties of signals.