DM74LS491 Overview
The ten-bit counter can count up count down set and load 2 LSB’s 2 MSB’s and 6 middle bits high or low as a group All operations are synchronous with the clock SET overrides LOAD COUNT and HOLD LOAD overrides COUNT COUNT is conditional on CIN otherwise it holds All outputs are enabled when OE is low otherwise HIGH-Z The 24 mA IOL outputs are suitable for driving RAM PROM address lines in video graphics systems.