DESCRIPTION
All changes of the Q outputs (except due to the asynchronous Master Reset in the LS161A) occur as a result of, and synchronous with, the LOW to HIGH transition of the Clock input (CP). As long as the set-up time requirements are met, there are no special timing or activity constraints on any of the mode control or data inputs. Three control inputs — Parallel Enable (PE), Count Enable Parallel (CEP) and Count Enable Trickle (CET) — select the mode of operation as shown in the tables below. The Count Mode is enabled when the CEP, CET, and PE inputs are HIGH. When the PE is LOW, the counters will synchronously load the data from the parallel inputs into the flip-flops on the LOW to HIGH transition of the clock. Either the CEP or CET can be used to inhibit the count sequence. With the PE held HIGH, a LOW on either the CEP or CET inputs at least one set-up time prior to the LOW to HIGH clock transition will cause the existing output states to be retained. The AND feature of the...
onsemi
