The 'LS597 comes in a 16-pin package and consists of an 8-bit storage latch
feeding a parallel-in, serial-out 8-bit shift register. Both the storage register
and shift register have positive-edge triggered clocks. The shift register
also has direct load (from storage) and clear inputs.
The 'LS598 comes in a 20-pin package and has all the features of the 'LS597
plus 3-state I/O ports that provide parallel shift register outputs and also
has multiplexed serial data inputs.