I gotta give credit to the PIC!

[Krumlink]

3v0 and I were doing a lesson, and we successfully programmed a 18F1320 PIC (18pin) to do a fancy flasher. After we were finished with it, I decided to run it stand alone. I hooked up a 9v Battery directly to the PIC without thinking. for 5 MINUTES it was connnected up. It was not flashing so I looked and saw the non existant regulator. I took the 9v from the PIC quickly and hoped it would work. I hooked it back up the the Inchworm+ and it reprogrammed and is still working! I was suprised that the little pic withstood 9V for over 5 minutes!

I gotta give credit to it!

 

[justDIY]

goes to show how impotent a 9v battery is! glad your pic survived

 

[bananasiong]

Wow you're lucky. I've blown out two PICs without putting any current limiting resistor to the LED

 

[blueroomelectronics]

PICs are pretty tough little beasts. LCDs not so much.

 

[Funny NYPD]

Wow you're lucky. I've blown out two PICs without putting any current limiting resistor to the LED

That's sad to hear. Did you use PICs source the current? Or have an external power source for the LEDs?

 

[bananasiong]

Yeah, I used PIC to source the LED.

 

[Gayan Soyza]

Load a big long program & see how it works if you are lucky will still contains all the RAMs if you are unlucky??????????????

I recently burned a PIC recently giving over voltage.
After burning it I gave a 3V supply & checked. The PIC starts to heat up quickly & not working.It was internally shorted.

 

[Krumlink]

I guess I win then

 

[Funny NYPD]

Yeah, I used PIC to source the LED.

Did you also return the current back to the Chip?
Microchip FAE claims it is quite safe to drive LED directly without damage either the Micro or the LED.

 

[Gayan Soyza]

If you are driving with a low duty cycle no problem & no need extra resister.If not need a 50 cent resister.

 

[bananasiong]

No resistor, no duty cycle (100 % I mean )
I source the LED directly from the PIC's output, cathode was connected to the ground.
I didn't know about current limiting resistor for the PIC last time

 

[Gayan Soyza]

same here i also not adding resisters for some fancy circuits

Here is an example of mine but the code is adjusted for varying duty cycles the 100% comes in very smaller time so no time to burn or heat the LED.To morrow I'll try to get a video of this project.

 

[Nigel Goodwin]

No resistor, no duty cycle (100 % I mean )
I source the LED directly from the PIC's output, cathode was connected to the ground.
I didn't know about current limiting resistor for the PIC last time

Really you're asking for trouble, you wouldn't stick an LED directly across a battery, so why should you do so on a PIC?.

PIC's don't provide current limited outputs, they merely specify a maximum safe current - however, they are extremely hardy devices, but abusing anything is never a good idea.

 

[OY2L]

Use always a resistor in series with a LED everything else is BAD pratice, if it's not are a blinkled having often hava a internal resistor

 

[atferrari]

A 16F877, working basically to drive some LEDs got fried when Vdd applied was close to 6V. Died on the spot.

A 18F452 survived being inserted into the breadboard (and turned on) with pin 1 in place of the 2 and so on. It was HOT to touch.

Two 16F877 survived after being inserted in the PICStart plus upside down.

A 16C57 (yes, some 12++ years ago) got one pin unusable (and consequently impossible to program) after shorting two consecutive pins (as outputs), one low and the other high.