The SN74ALS193AD is a 4-bit synchronous Up/Down Binary Counter with dual clock and clear. Synchronous counting operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous counters. The outputs of the four flip-flops are triggered on a low-to-high-level transition of either count/clock input. The direction of the count is determined by which count input is pulsed while the other count input is high. All four counters are fully programmable, that is, each output may be preset to either level by placing a low on the load input and entering the desired data at the data inputs. The output changes to agree with the data inputs independently of the count pulses. This feature allows the counters to be used as modulo-N dividers by simply modifying the count length with the preset inputs.
Look-ahead circuitry enhances cascaded counters
Fully synchronous in count modes
Parallel asynchronous load for modulo-n count lengths
