Core independent peripheral based ultrasonic ranging peripheral

摘要

A ranging function is implemented using a collection of core independent peripherals (CIPs) in a microcontroller without software overhead to the central processor during operation thereof. A pulse width modulation (PWM) peripheral generates a high frequency drive signal, a counter to set the duration of the PWM drive signal (pulse), and a second timer coupled to a comparator to measure the time it takes to receive back a reflection of the ranging signal from an object. The ranging peripheral starts ranging with ultrasonic pulses, and when corresponding reflected ultrasonic pulse are receives an interrupt signal is provided when the ranging measurement is complete. Time dependent sensitivity and/or gain adjustments are contemplated. The ultrasonic ranging peripheral uses on chip resources for most of its functions and therefore requires very few external components. It's set and forget nature may be based on CIP based timers, signal generators and configurable logic cells.