I have the schematic for my Connect4 project very nearly finished.

I'm going to use two AA batteries in series as my power supply, thus 
giving me 3 V. I'm going to use a voltage regulator called the LT1173-5 
to give me 5 V to power the PIC16F887.

I'll use the 5 V to power the microcontroller and also as a voltage 
reference for any pull-up resistors, but everywhere else I'm going to 
use the 3 V directly from the batteries for the driver chips which drive 
the LED's and also the piezo speaker.

My board will have a switch for turning the game on and off. This switch 
will make or break the connection to the output of the 5 V voltage 
regulator. This switch will have *no* effect on the 3 V supply that 
comes directly from the batteries to the driver chips. So long as 
there's batteries in the device, there'll always be a 3 V supply going 
to the driver chips regardless of whether the power switch is on or off.

My board will have a 6-pin header for hooking the Pickit2 up to it to 
program and debug it. Before the Pickit2 is hooked up, the power switch 
should be turned off. When the power switch is turned off, there'll be 
no 5 V supply for the microcontroller, nor will there be a 5 V reference 
for the pull-up resistors. There *will* however always be 3 V going to 
the driver chips.

When you hook the Pickit2 up to it, the Pickit2 will detect that there's 
no 5 V supply and so it will supply 5 V itself. That's the idea in anyway.

Here's my current schematic:

http://freepdfhosting.com/uploads/6640a7ea8a.pdf

The PDF file is high resolution so you can zoom in.

Here's my first question:
1) Do I need the RC circuit on the Vpp pin of the 887? I heard something 
about being able to use an internal pull-up?
2) I remember someone saying something about putting capacitors across 
the power supply as well... so if you could please give me pointers on that.

Please feel free to offer whatever *constructive* criticism you can. 
Also, you'll notice that I have 3 pins to spare on the microcontroller. 
If you can think of something frivolous to do with them then please let 
me know!

Also, can anyone suggest a good 3-pin LED for me to use? The forward 
voltage must be less than 3 V and also I'd rather if the colour 
combination wasn't Red and Green because most colour-blind people have 
difficulty distinguishing these colours. Also, I want the LED's to be 
nice and bright to that they can be seen lit outside in daylight. (My 
last project board looked crap because the LED's were very dim in daylight).

Comments, questions, suggestions welcomed :-)

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