Need a chip

[davidleeroth]

Basically the chip should have the same features as the lovely 74157 IC but
it should stay "pulling" on the input it was ordered by the select pin once
it received voltage on Vcc.  

So, no matter what voltage the select pin receives after receiving voltage
on Vcc, the input can't be changed but resetting the whole chip.

All the chips or relays I can think of function by changing the polarity.    

[NFG]

If it helps your search, you're looking for a latching chip, one that will 'latch' onto the signal and hold the output until the chip is signalled to reset.  I don't know of any, but that term should help you find one.

[davidleeroth]

Thanks Lawrence, not being familiar with these fancy terms does make it a bit hard to search what one wants.    

[hemphacker]

74373 or 74573 are a couple of latches and RadioShack sells them (along with many other places). For these two chips, you need to tie the OE (output enable) to ground and the LE (latch enable) to ground. When you want to capture the input, toggle the LE pin high then low. (all this is assuming that LE and OE are low active)