Stupid newb (Moi) has some questions!

Alrighty, I'm rather new to electronics allaround, but for X-mas I ordered a bit of PIC uC stuff and just got it not too long ago. A few basic questions I have:

Do I have a very specific power min/max in terms of current? I certainly don't want to cook the thing, especially since it isn't the most affordable thing to replace over and over. The specific uC I have is the PIC16F876A, just in case different IC's have different power ratings (Doubtful, but hey, what do I know?)

Next! Does the aforementioned PIC have any internal oscillator speed so I can skip having to hunt down 30pF caps for the 20Mhz oscillation?

Annnnnd, is the output of the data pins the same as my input voltage, or slightly lower?

ArtemisGoldfish said:

Alrighty, I'm rather new to electronics allaround, but for X-mas I ordered a bit of PIC uC stuff and just got it not too long ago. A few basic questions I have:

Do I have a very specific power min/max in terms of current? I certainly don't want to cook the thing, especially since it isn't the most affordable thing to replace over and over. The specific uC I have is the PIC16F876A, just in case different IC's have different power ratings (Doubtful, but hey, what do I know?)

Click to expand...

Like almost any electronic device, the PIC will only take what it needs - which in a PIC's case is VERY little. Output wise you can supply about 20-25mA from an output pin - but you are also limited by the total amount the chip can supply - details are given in the datasheet.

Next! Does the aforementioned PIC have any internal oscillator speed so I can skip having to hunt down 30pF caps for the 20Mhz oscillation?

Click to expand...

No it doesn't have an internal oscillator.

Annnnnd, is the output of the data pins the same as my input voltage, or slightly lower?

Click to expand...

It's slightly lower, but not of any concern - they are logic inputs and outputs, and behave as such - with the obvious exception of pins set to be analogue inputs!.

Do I have a very specific power min/max in terms of current? I certainly don't want to cook the thing

Click to expand...

Just power it with 5Vdc of the correct polarity and the smoke will stay inside.

Does the aforementioned PIC have any internal oscillator speed so I can skip having to hunt down 30pF caps for the 20Mhz oscillation?

Click to expand...

You can use the RC oscillator option if you don't need an accurate clock speed higher than 4Mhz.
Also look into a 20Mhz ceramic resonator with built in caps if the crystal hunt gets you down. I've used the ZTT-20.00MX with PICs and it is available from mouser and digikey, etc.

Yeah, you can't let the magic smoke out the little black box or the PIC (or any other IC for that matter) stops working.

It's not that hard to find pF capacitors. Just don't go to radioshack or something. I find that my local electronics stores carries a ridiculous number of itty bitty precision caps, presumably for clocks. I can actually find capacitors for crystals more easily than 0.1uF bypass capacitors. Maybe I'm wrong, but you're in New York...I thought you could get almost anything there it's such a large city?

You can also order ten 33pF caps from from www.glitchbusters.com for $0.49 (+2.95 shipping, $1.95 for orders $14+). He is closing down soon and you can also order other bits and pieces that you need.

If the magic smoke gets out you are done for sure. But talk about magic.

If you are in a hurry to play with the chip and "JUST" need the 33pF caps (you have a 4-20Mhz Xtal). If you have some wirewrap or small gauge insulated wire. Like 26 gauge.

Take some wirewrap, bend it in 1/2, and twist it tight 3 times. Trim/strip the bottom two wires short and cut the loop off the top. Poof.. ~33pF cap. There is an old website with this information on it. If it does not work trim a little off, but I have never had too.

I have done this to many times to count (in the past; years ago) and it works very well. I recall 3 and 33pF. This is just to play with the chip, I would never count on this with viberation, etc..

Ah, thanks everyone. I wondered about the whole current thing because I had previously tried to make an audio amp with a pretty dern good IC and I put alittle too much current through it, causing it to explode and a little piece of the package to fly off and hit me in the face.

Anyways, like I said, thanks everyone!

Yeah, you need amplifiers (and maybe DACs) for things like that. The PIC can't provide too much power on it's own- not enough magic smoke inside.