Abstract: A method includes projecting light to obtain a reference measurement using a first photoresistor; collecting dust on a platform during a collection time interval; and projecting light across the platform to obtain a dust measurement using the first photoresistor or a second photoresistor.

Abstract: A control unit for a functional processor is disclosed which minimizes programming complexity by eliminating data transfers and the transfer control associated with two level memory systems and which improves flexibility in program task changeovers in pipelined arithmetic architectures. This is accomplished by employing common page addressing for accessing memory address stacks for storing either main memory addresses or address increments, coefficient address stacks for storing coefficient memory addresses or address increments, and microinstruction sequencing control branch stacks for storing branch and loop control parameters. This permits chaining of long sequences of signal processing subroutines without external control and the associated execution time overhead.