Abstract: An apparatus for preventing physical intrusion on a data bus includes a data bus state sensor coupled to the data bus for monitoring a state of the data bus, a power circuit for generating multiple voltages supplied to functional circuitry in the apparatus, and a variable override circuit. The variable override circuit receives one or more voltages from the power circuit and selectively gates the voltages onto the data bus as a function of one or more control signals. A controller coupled to the variable override circuit, the power circuit and the state sensor receives state information from the state sensor and generates the control signals in response to detection of physical intrusion on the data bus. The controller controls a voltage level of at least one of the voltages generated by the power circuit for overriding the data bus when physical intrusion is detected on the data bus.

Abstract: An apparatus for preventing physical intrusion on a data bus includes a data bus state sensor coupled to the data bus for monitoring a state of the data bus, a power circuit for generating multiple voltages supplied to functional circuitry in the apparatus, and a variable override circuit. The variable override circuit receives one or more voltages from the power circuit and selectively gates the voltages onto the data bus as a function of one or more control signals. A controller coupled to the variable override circuit, the power circuit and the state sensor receives state information from the state sensor and generates the control signals in response to detection of physical intrusion on the data bus. The controller controls a voltage level of at least one of the voltages generated by the power circuit for overriding the data bus when physical intrusion is detected on the data bus.