Thanks for all the replies. It seems like it was a better question than I thought. This is a one-off hobby project, so component cost isn't much of issue. I'll go with the bigger pic because it is easier. Jason ----- Original Message ----- From: "Eisermann, Phil [Ridg/CO]" To: Sent: Tuesday, April 13, 2004 11:31 AM Subject: Re: [PIC:] Is it better to use Shift Registers or lots of I/O? > pic microcontroller discussion list wrote: > > As with most things in EE, it looks like the answer to this question > > depends on your individual problems and design goals. > > I think this about sums it up. It's always a tradeoff. Cost has been > mentioned already, but I feel like jumping in on this thread > > Cost and complexity are almost always interrelated. Cost is more > than just component cost. I personally think that component cost > only becomes relevant when you start talking about 10's or 100's of > thousands of boards. I look at it in terms of design time e.g. > engineering salary. In this case, DigiKey price for 100 16F872-ISO > is $2.81. 100 12F629-ISO plus 74HC164 is 1.32. Difference is $1.49 > times 100 units = $149 dollars. How much more it costs to design in > a shift register depends on many factors, but I doubt its more than > 30 minutes to an hour even if you include PCB layout. As long as this > isn't your first PIC project, clocking out serial data is trivial. So > the cost difference shrinks to maybe $100. Its pretty much a negligible > difference at low volumes in any case. But at higher volumes, the > component costs start to make a difference. > > In general, the simpler the design, the less can go wrong, the less > time it takes to design and develop, and the cheaper it becomes. > Unless you are doing it as a hobbyist, time is not free. > > So, there is no right answer to the original question, just guidelines :) > > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.