Abstract: Method and circuitry for automatic resetting of an integrated circuit upon power up handles multiple clock sources and minimizes power dissipation. A robust voltage sensing circuit detects power up and triggers resetting of most of the circuit with the exception of the initialization circuit that includes an internal oscillator. After the circuit determines that the internal oscillator signal has settled, contents of non-volatile register are read to select the clock source for the circuit. Upon successful selection and clean up of system clock, the reset is removed.

Abstract: A system and method for device authentication are disclosed. In one embodiment, a random security code is generated during a boot operation to verify authenticity of a device. The random security code may comprise a rolling code based on a static number and a seed number, where the static number does not change between successive boots and the seed number changes between boots. A random number generator algorithm may provide the seed number.

Abstract: Method and circuitry for automatic resetting of an integrated circuit upon power up handles multiple clock sources and minimizes power dissipation. A robust voltage sensing circuit detects power up and triggers resetting of most of the circuit with the exception of the initialization circuit that includes an internal oscillator. After the circuit determines that the internal oscillator signal has settled, contents of non-volatile register are read to select the clock source for the circuit. Upon successful selection and clean up of system clock, the reset is removed.

Abstract: Method and circuitry for automatic resetting of an integrated circuit upon power up handles multiple clock sources and minimizes power dissipation. A robust voltage sensing circuit detects power up and triggers resetting of most of the circuit with the exception of the initialization circuit that includes an internal oscillator. After the circuit determines that the internal oscillator signal has settled, contents of non-volatile register are read to select the clock source for the circuit. Upon successful selection and clean up of system clock, the reset is removed.

Abstract: A programmable multi-scheme clocking circuit supports multiple applications. In one implementation, the clocking circuit includes multiple clock sources such as a crystal oscillator, a RC oscillator, an internal oscillator, and an external clock. Each of the clock sources can be enabled by a respective control signal. A multiplexer couples to the clock sources and provides a clock signal from one of the clock sources as the output clock signal. External support circuitry (e.g., external tank circuits) for some of the clock sources (e.g., the crystal oscillator and the RC oscillator) can be coupled to the clocking circuit through one or more device pins. The pins to support the crystal oscillator, the RC oscillator, and the external clock signal are shared so that no additional device pins are required.