Patent ID: 7675447

Claim:
A method comprising: using an eight-bit processor to set a programmable internal reference voltage source to output a first reference voltage; using the eight-bit processor to establish a first signal path such that the first reference voltage is supplied via the first signal path onto a first differential input lead of a sigma-delta analog-to-digital converter (SDADC); using the eight-bit processor to establish a second signal path such that a pyroelectric sensor output signal present on a terminal is supplied from the terminal via the second signal path onto a second differential input lead of the SDADC; performing a plurality of analog-to-digital conversions and thereby generating a plurality of ADC digital output values, wherein each ADC digital output value has more than ten bits; low pass filtering the plurality of ADC digital output values and thereby generating a plurality of processed sample values, wherein the low pass filtering is performed by a hardware state machine that does not fetch instructions; and using the plurality of processed sample values to perform a motion detection decision function, wherein the SDADC, the eight-bit processor, the programmable internal reference voltage source, the first signal path, the terminal, and the second signal path are parts of a single microcontroller integrated circuit.