DM7556 - National Semiconductor

DM7556 TRI-STATE Programmable Binary Counters

These circuits are synchronous edge-sensitive fully-programmable 4-bit counters The counters feature both conventional totem-pole and TRI-STATE outputs such that when the outputs are in the high impedance mode they can be used to enter data from the bus lines In addition the clear input operates completely independent of all other inputs During the programmi.

Features

Y Y Y Y Y Typical clock frequency 35 MHz TRI-STATE outputs Fully independent clear Synchronous loading Cascading circuitry provided internally Connection Diagram Dual-In-Line Package TL F 6588
  – 1 Order Number DM7556J or DM8556N See NS Package Number J16A or N16A Function Table Control Inputs LOAD H H H H L H H CE X X X X H L L CLK X X L L OD L H L H L L H Reset H H L L L L L I OA L Z QA0 Z a Z I O Ports I OB I OC I OD L Z QD0 Z d Z QA L L QA0 QA0 A Active Outputs QB QC QD L L QD0 QD0 D u u u L L Z Z QB0 QC0 Z Z b c COUNT Z Z L L L L QB0 QC0 QB0 QC0 B C COUNT COUNT The I O pins are us.