SN74HC193D (TEXAS INSTRUMENTS)

The SN74HC193D is a 4-bit Synchronous Up/Down Counter (dual clock with clear), operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincidentally with each other when so instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters. The outputs of the four flip-flops are triggered on a low-to-high-level transition of either count input. The direction of counting 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 simply by modifying the count length with the preset inputs.