[SOLVED] PIC16F877A not working even after bieng programmed successfully using ICPROG

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yes i think You are rite.. I use 10 ms delay during that 6 times high /low on port B , but LEDes are not blinking with the same delay as specified they are blinking with their wish..
 

What are you using as a power supply?

Do you have a slower crystal, 4MHz?

Also remove the programmer and see if the LED stablizes.

BigDog
 

I have no doubt you have programmed the device successfully.

Stability is the issue. Do you have the crystal and capacitors as close to the PIC as possible?

BigDog
 


One other thing have you installed a 100nF capacitor across the Vdd and Vss pins (5v to GND), keeping it a close as possible to the PIC?
Click to expand...

why it need to be close as possible while if we place it a little far then it's the same connection.?
I believe this trick also I have experienced about this and Im puzzled why it needs to be close.. hmmm
 

Oh Sir thanks Alot for Your such a precious time... :-D
That was issue of supply .. I dont know why but i remove regulator and give direct 5V from supply it's working now.. :S
 

Well in regards to the crystal any relatively high frequency signal path should be keep to a minimum.

Stray capacitance, EMI, etc all play a role in the ability to deliver a clean clock signal.

The capacitor across the Vdd and Vss absorbs any EMI or noise on the +5V and GND lines keeping it to a minimum.

Does this make sense?

BigDog

---------- Post added at 05:17 ---------- Previous post was at 05:16 ----------

Glad to hear it. Good clocks and power supplies are essential with almost any MCU.
 

I dont know why.. As regulator was also giving 5 V ..

---------- Post added at 09:23 ---------- Previous post was at 09:19 ----------

Well thanks Romel and bigdogguru... ! Happy that You people are here to help beginners like us :razz:
 

I would have to see the regulator circuit to be able to give an opinion.

It obviously was not providing a stable 5V supply, perhaps noise, etc.

Did you put that 100nF capacitor between 5V and GND as close as possible to the PIC?

BigDog
 

Yes.. I did... But I think my supply still not giving stable voltages .. I should use regulator ..
I was using regulator 7805..

---------- Post added at 09:38 ---------- Previous post was at 09:30 ----------

hey guys my original program is also working...

---------- Post added at 11:28 ---------- Previous post was at 09:38 ----------

hello .. Again :smile:
my program shows output like this on virtual terminal (simulation)

this is due to line present in my code this is
Code: 
UART1_Write(13);
but in real hype terminal it is overwriting the same first line continuously..

Any Help ...
thank you..
 

illegal121 said:
but in real hype terminal it is overwriting the same first line continuously..
Click to expand...

You can output a newline character (\n} after each successive line.

You can also add a delay in your program after each outputted line, this will slow down the display on hyperterminal.

BigDog
 

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