STMicroelectronics SPC572L series Reference Manual page 1742

JTAG Controller (JTAGC)
To initialize the JTAGC block and enable access to registers, the following sequence is
required:
1. Set the JCOMP signal to the JTAGC enable value, thereby enabling the JTAGC TAP
controller
2. Load the appropriate instruction for the test or action to be performed
1742/2058 DocID027809 Rev 4
RM0400