sn54ls696,sn54ls697,sn54ls699,
These low-power Schottky LSI devices incorporate synchronous up/down counters, four-bit D-type registers, and quadruple two-line to one-line mulTIplexers with three state outputs in a single 20-pin package. The up/down counters are programmable from the data inputs and feature enable P\ and enable T\ and a ripple-carry output for easy expansion. The register/counter select input R/C\, selects the counter when low and the register when high for the three-state outputs, QA, QB, QC, and QD. These outputs are rated at 12 and 24 milliamperes (54LS/74LS) for good bus driving performance.
Both the counter CCK and register clock RCK are posiTIve-edge triggered. The counter clear CCLR\ is acTIve low and is asynchronous on the 'LS696 and 'LS697, synchronous on the 'LS699.