Hi. 

I'm very new to this and it's just a hobby (I'm a full time software
developer but I've never gotten into hardware) so my question may be pretty
dumb... but here goes anyways: 

I want to control two 7-segment LEDs using a 12F675. Obviously I don't have
enough pins to do this straight up, so I figured I could use a 74HCT259
8-bit addressable latch as a 3-to-8 demultiplexer and hook up the common
cathodes on the seven-segments to pins on the PIC that can act as sinks. 

(I'm not concerned about whether or not this is a feasible solution to the
problem - I'm more concerned with just getting to at least try out my idea)

What I'm confused about is the operation of the latch. It seems like I would
have to set the 3 inputs to the latch (not a problem), set the associated
cathode pin on the PIC to act as a sink (also not a problem), and then
toggle the MR pin on the latch to reset the current output to 0, then toggle
the LE pin to remember my selection. That means I would need a total of 5
pins to operate the latch... which doesn't make sense to me because then you
are really only saving three pins on the PIC - and then I still don't have
enough pins left to control the cathodes. 

Am I missing something here? 

(http://rocky.digikey.com/WebLib/Texas%20Instruments/Web%20data/CD74HC(T)259
.pdf)

Thanks in advance!

-Steve W

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