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In addition to the BC_1 Boundary Scan cell type, there are more Boundary Scan cell types that can be used to create a Boundary Scan Register and implement the IEEE 1149.1 operations within a Boundary Scan device. The type(s) of Boundary Scan cell(s) implemented within a device are listed in the BSDL. Basic Cell (BC)_0 through BC_7 are the standard Boundary Scan cell types commonly found in an IEEE 1149.1 compliant Boundary Scan device. You may ask the question, โ€œAre there more Boundary Scan cells than BC_0 through BC_7?โ€
Boundary Scan Description Language (BSDL) provides a description of testability features within ICs that comply with the IEEE 1149.1 Standard (hereinafter used interchangeably with the term โ€œJTAGโ€). Having a good understanding of the BSDL leads to a deeper knowledge of JTAG, that in turn grants insight into the technology behind IEEE 1687, also known as IJTAG.
With IEEE 1687 (aka IJTAG) making its way into a great many chips as a mainstream mechanism for access and control of embedded instrumentation, Iโ€™ve taken an interest in explaining this often complicated technology in simple terms. Iโ€™ll start with describing the syntax, semantics and overall structure of Instrument Connectivity Language (ICL) and Procedural Description Language (PDL).
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