Hi Steve,

Most Holtek encder/decoder ICs have internal pull-ups, so floating these pins is the same
as connecting them to Vcc. This should be in the data sheet. The 8-bit series are tri-state.

But I never allow them to float. Especially in an application with an oscillator or embedded
controller that's going to indroduce a ton of digital switching noise to the power supply rails.

I've only seen maybe 1 in 10K failures with a set of Holtek encoder/decoder ICs. 9 times out
of 10 it's something simple like noise, a single bit difference in the address, bad connection,
wrong oscillator resistor value (voltage dependant), or just plain wired wrong that's the
cause of failure.