the act16646 are 16-bit bus transceivers consisting of d-type flip-flops and control circuitry with 3-state outputs arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. the devices can be used as two 8-bit transceivers or one 16-bit transceiver. data on the a or b bus is clocked into the registers on the low-to-high transition of the appropriate clock (clkab or clkba) input. figure 1 illustrates the four fundamental bus-management functions that can be performed with the bus transceivers and registers. output-enable and direction-control (dir) inputs are provided to control the transceiver functions. in the transceiver mode data present at the high-impedance port may be stored in either register or in both. view all in datasheet