Various aspects include a clock monitoring unit/component that is configured to repeatedly/continuously monitor a clock with the speed required to support automobile automation systems without the use of a reference clock. The clock monitoring unit/component may be configured to identify, report, and/or respond to variations or abnormalities in the monitored clock, and initiate an action to prevent the variation from causing or resulting in a failure or a vulnerability to attack. The clock monitoring unit/component in the various aspects may be configured, organized, or arranged to operate so that the circuit is immune or resistant to manipulation, modification, tampering, hacks, and other attacks.