Hello,

I am trying to design a circuit using the 8052 that will perform acoustic depth ranging. The application has a keypad, LCD display, and external power management ICs. I have a question--to obtain "time of flight" information and to produce the frequency and the duration of the pulse, should I use circuits that are external to the 8052? These circuits would use a crystal oscillator and some digital logic to produce the frequency; and the circuits will also ensure that the pulse is of a proper duration. In this application, I am looking for relatively high accuracy (~0.01m, up to a distance of 5 m) in environments that can reach -40 degrees C. What are the benefits of using external circuits, as opposed to just using the 8052? In this setup, the 8052 would only be used for data processing, and the external circuitry would do all the work. Alternately, should I simply use the 8052 (instead of an external circuit) to produce the pulse frequency (and ensure that the pulse is of a proper duration)?

What are the pros and cons of such an approach? Which one should I use?

Thank you in advance for your time and assistance.

Nicholas Kinar