MAXPORTSIZE can be set to any architecturally defined value.

MAXPORTSIZE appears in the System Configuration Register. If CoreSight ETM11 is programmed with a port size greater than that specified by MAXPORTSIZE, the port size supported bit, bit 10 of the ETM System Configuration Register, is LOW. The debugger must check that this bit is HIGH before a debugging session to ensure that a valid port size has been programmed.