What is a compliance enable pin?

Compliance enable pins must be held with stable logic states as described in the boundary scan description language (BSDL) before the device can be engaged in any 1149.1 boundary scan activities. The compliance enable pins must be continuously maintained in their stable logic states till the completion of the 1149.1 boundary scan test activities.

Example: Compliance enable pins declaration in the BSDL:

Attribute COMPLIANCE_PATTERNS of Annex_A_Chip : entity is 
“(LSSD_A, LSSD_B, LSSD_P, LSSD_C1, LSSD_C2) (00011)”;