PIC16F84A input

I am building a small wheeled robot for a project and I am having trouble with the input on the PIC16F84A microcontroller. I want to make
some basic pushbutton/switch inputs on Port B. How do I wire this? Do I run a wire from the positive power rail to the switch and then to the input, or from the input to the switch to the negative power rail? Also, will I need a resistor in there to keep the circuit from getting damaged?
Also, how does the input appear programming-wise? Does the input pin simply return a 1 or a 0? I'd greatly appreciate any help on the matter.
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Garrison,
Now is the time to brush off your analytical skills, that alone will answer your questions. But, until then... The best way to implement this is to use a pull up resistor from the IO line to 5V. 10K is a good value. Now you connect the common of the switch to the IO line and the NO (normally open) side of the switch to the ground. The pin will read '1' until the button is pressed, then it will read '0'. Since you appear to be a newcomer to the art I strongly suggest that you put a buffer resistor between the IO line of the PIC to the switch. In this way if you goof, make the IO line an output and them short that to ground via the switch you won't let the magic smoke out of the PIC.
Now on to the other bit, why on Earth are you using a 16F84A? That is last century's news. You should be using something like a 16F628A or 16F88, items with built in UARTs, more interrupt sources and way better hardware peripherals - Also, if you check the part costs, these newer parts are cheaper.
DLC
: I am building a small wheeled robot for a project and I am having : trouble with the input on the PIC16F84A microcontroller. I want to make : some basic pushbutton/switch inputs on Port B. How do I wire this? Do I : run a wire from the positive power rail to the switch and then to the : input, or from the input to the switch to the negative power rail? : Also, will I need a resistor in there to keep the circuit from getting : damaged?
: Also, how does the input appear programming-wise? Does the input pin : simply return a 1 or a 0? I'd greatly appreciate any help on the matter.
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Or even an 18fxxx as the prices are dropping. Also there is the free microchip student version of the C18 compiler if you use c. <http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId 06&dDocName=en010014&part=SW006011>
18f's are faster and a lot have a good bit more flash and ram for not much more.
16fxx code will run a lot of the time without changes for the 18f's, just have to use the 18f fuse settings.
Think I'm going to find the time to put a short doc on how to change 16f code to 18f on my site. Probably need a few 18f examples.
In the middle of writing up how to get eclipse and gnu arm installed and running on os x as an addon to the doc on new micros on getting eclipse and gnu arm running on windows.
Add it to this weekend's (long weekend) list this doc , uni HPC fortran assignment , uni grid computing report, uni group assignment on Terrahertz imaging.
Also don't forget to check the circuit cellar site their Philips arm7 contest starts tomorrow.
Alex
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Garrison Benson wrote:

schematic and routines at: http://www.dontronics.com/psbpix/button.html
Don...
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