Welcome into PIC world

**shafi008** · - 24th April 2009, 04:40

Hello This is my first time in PIC's world.

I am using 16f84a with Melabs programmer.
I am trying to flash a led at PortB.0 and here is the code and
circuit diagram is at http://www.trendztechnologies.net/good.jpg

loop:
High PORTB.0 ' Turn on LED connected to PORTB.0
Pause 1000 ' Delay for .5 seconds

Low PORTB.0 ' Turn off LED connected to PORTB.0
Pause 1000 ' Delay for .5 seconds

Goto loop ' Go back to loop and blink LED forever
End

At all the ports i have 0.74 reading.
LED is constant but it is not blinking.

Could you please suggest me what's wrong with this.

Syed

**ScaleRobotics** · - 24th April 2009, 05:02

Its a little hard for me to follow your "diagram", but it doesn't look like your resonator is grounded to me..... The center pin should go to ground, no?

Also try trisb command.

Check out:
http://www.picbasic.co.uk/forum/showthread.php?t=7906

Walter

**Archangel** · - 24th April 2009, 05:08

Originally Posted by scalerobotics

Its a little hard for me to follow your "diagram", but it doesn't look like your resonator is grounded to me..... The center pin should go to ground, no?

Also try trisb command.

Check out:
http://www.picbasic.co.uk/forum/showthread.php?t=7906

Walter

Looks like the PIC is not hooked up to ground at all, notice the center pin of the resonator goes to the PICs ground leg but I see no ground wire there.

**shafi008** · - 24th April 2009, 15:12

Hi one of the document says the VSS should be connected to the middle pin of resonator, thats why it was connected to Vss and the pullup resistor i have used for MCLR is 4.7K. the other end of pullup resistor the voltage was around 2+_ volts.

As you said today let me try by connecting the resonator middle pin to Ground , i will post you the output later.

**Archangel** · - 24th April 2009, 18:25

Hello Syed,
I am looking at the picture you posted, you have a wire going from the center of the resonator to pin 5 of the PIC but no wire from Pin 5 to ground. It must be grounded to the 5v supply, otherwise the PIC receives no power.

**Archangel** · - 24th April 2009, 18:39

Originally Posted by Joe S.

Hello Syed,
I am looking at the picture you posted, you have a wire going from the center of the resonator to pin 5 of the PIC but no wire from Pin 5 to ground. It must be grounded to the 5v supply, otherwise the PIC receives no power.

See Attachment:
<img src=>http://www.picbasic.co.uk/forum/atta...1&d=1240594618