Electronic appliance controller with flexible program and step duration

Abstract

An electronic sequence type controller structure having a high degree of flexibility in programming the time durations of particular steps in the program. The controller which includes a digital program sequence counter capable of stepping from one state to the next in response to inputted clock pulses, each state representing a particular program step. A programmable digital counter, programmed by a timer setting control, is operable to count inputted clock pulses and to output a signal when the number of clock pulses corresponding to a programmed time duration have been inputted. A program memory is responsive to the state of the program sequence counter for directing the timer setting control to program a time duration desired for any particular program step into the programmable timer. To direct the overall operation to effect periodic program advancing operations there is provided a control logic means. In operation, the control logic means is operable to direct a clock pulse to the programmable timer for each program advancing operation in the event a signal has not been received from the programmable timer and a program step is therefore in progress. When a program step is completed, a signal is received from the programmable timer and the control logic means is then operable to direct a clock pulse to the program sequence counter to cause stepping to the next program step, whereupon the program memory directs the timer setting control to program a new time duration into the programmable timer.