Target Interface JTAG

JTAG is the acronym for Joint Test Action Group. In the scope of this document, "the JTAG standard" means compliance with IEEE Standard 1149.1-2001.

Test access port (TAP)

JTAG defines a TAP (Test access port). The TAP is a general-purpose port that can provide access to many test support functions built into a component. It is composed as a minimum of the three input connections (TDI, TCK, TMS) and one output con- nection (TDO). An optional fourth input connection (nTRST) provides for asynchro- nous initialization of the test logic.