On Thu, Jun 26, 2008 at 5:50 PM, Tom=E1s =D3 h=C9ilidhe w= rote: > > 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. Why do you need 5V? The 16F887 is happy at 3V. It's important to read the "electrical characteristics" part of the datasheet when you're doing the circuit design. Here's the datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/41291E.pdf See figure 17-1. I don't know how to say this any clearer. Regards, Mark markrages@gmail -- = Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist