The CoreSight debug system is spread across three power domains. Although all power-domains should be turned on, the basic JTAG functions work as long as the low-power domain (LPD) and PL power domain (PLPD) are active. The PL TAP controller is required to run a boundary scan (BSCAN). The DAP controller has components in the full-power domain (FPD) for APU debug. See Table: JTAG and CoreSight Split Between Power Domains.