SDLS191 - JANUARY 1981 - REVISED MARCH 1988
PRODUCTION DATA documents contain information current as of publicationdate. Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily include testingof all parameters.
These devices consist of bus transceiver circuits, D-type flip-flops, andcontrol circuitry arranged for multiplexed transmission of data directly fromthe data bus or from the internal storage registers. Enable GAB and G\BA are provided to control the transceiver functions. SAB and SBA controlpins are provided to select whether realtime or stored data is transferred.A low input level selects real-time data, and a high selects stored data.The following examples demonstrate the four fundamental bus-management functionsthat can be performed with the 'LS651, 'LS652, and 'LS653.
Data on the A or B data bus, or both, can be stored in the internal D flip-flopby low-to-high transitions at the appropriate clock pins (CAB or CBA) regardlessof the select or enable control pins. When SAB or SBA are in the real-timetransfer mode, it is also possible to store data without using the internalD-type flip-flops by simultaneously enabling GAB and G\BA. In thisconfiguration each output reinforces its input. Thus, when all other datasources to the two sets of bus lines are at high impedance, each set of buslines will remain at its last state.
The SN54LS651 through SN54LS653 are characterized for operation over thefull military temperature range of -55°C to 125°C. The SN74LS651 throughSN74LS653 are characterized for operation from 0°C to 70°C.
View more information about generic part numbers:SN74LS651, SN74LS652, SN74LS653
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