74LS191.pdf Synchronous 4-Bit Up Down Counters with Mode Control DM54LS190 DM74LS190 DM54LS191 DM74LS191 May 1989 DM54LS190 DM74LS190 DM54LS191 DM74LS191 Synchronous 4-Bit Up Down Counters with Mode Control General Description These circuits are synchronous reversible up down coun- Two outputs have been made available to perform the cas- ters The LS191 is a 4-bit binary count……