MC74F543

The MC74F543 contains two sets of eight D-type latches, with separate input and controls for each set. For data of MC74F543 flow from A to B, for example, the A-to-B Enable (EAB) Input must be LOW in order to enter data from A0A7 or take data from B0B7, as indicated in the Function Table. With EAB LOW, a LOW signal on the A-to-B Latch Enable (LEAB) input makes the A-to-B latches transparent; a subsequent LOW-to-HIGH transition of the LEAB signal puts the A latches in the storage mode and their outputs no longer change with the A inputs. With EAB and OEAB both LOW, the 3-State B output of MC74F543 buffers are active and reflects the data present at the output of the A latches. Control of data flow from B to A is similar, but using the EBA, LEBA, and OEBA inputs.