SN74HC193-Q1，PDF（4-Bit Synchro

The SN74HC193 device is a 4-bit synchronous, reversible, up/down binary counter. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change simultaneously with each other when dictated 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 (clock) input (UP or DOWN). 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 (LOAD) input and entering the desired data at the data inputs.