资 源 简 介
This synchronous, presettable, 4-bit binary counter has internal carry look-ahead circuitry for use in high-speed counTIng designs. Synchronous operaTIon is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable (ENP, ENT) inputs and internal gaTIng. This mode of operaTIon eliminates the output counting spikes that normally are associated with asynchronous (ripple-clock) counters. However, counting spikes can occur on the ripple-carry (RCO) output. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of CLK.
This counter is fully programmable. That is, it can be preset to any number between 0 and 15.
