DM54LS469

DM54LS469 DM74LS469 8-Bit Up Down Counter July 1989 DM54LS469 DM74LS469 8-Bit Up Down Counter General Description The ‘LS469 is an 8-bit synchronous up down counter with parallel load and hold capability Three function-select inputs (LD UD CBI) provide one of four operations which occur synchronously on the rising edge of the clock (CK) The LOAD operation loads the inputs (D7 – D0) into the output register (Q7 – Q0) The HOLD operation holds the previous value regardless of clock transitions The INCREMENT operation adds one to the output register when the carry-in input is TRUE (CBI e LOW) otherwise the operation is a HOLD The carry-out (CBO) is TRUE (CBO e LOW) when the output register (Q7 – Q0) is all HIGHs otherwise FALSE (CBO e HIGH) The DECREMENT operation subtracts one from the output register when the borrow-in input is TRUE (CBI e LOW) otherwise the operation is a HOLD The borrow-out (CBO) is TRUE (CBO e LOW) when the output register (Q7 – Q0) is all LOWs otherwise FALSE (CBO e HIGH) The output register (Q7 –Q0) is enabled when OE is LOW and disabled (HI-Z) when OE is HIGH The output drivers will sink the 24 mA required for many bus-interface standards Two or more ‘LS469 octal up down counters may be cascaded to provide larger counters Features Benefits Y Y Y Y Y Y Y 8-bit up down counter for microprogram-counter DMA controller and general-purpose counting applications 8 bits matches byte boundaries Bus-structured pinout 24-pin SKINNYDIP saves space TRI-STATE outpu...