Welcome into PIC world

[Archangel]

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

[shafi008]

Hi Guys,

Bad luck i tried changing another Pic16f84a
no work, i tried with multiple resonators and 4mhs with 47 / 10 pf that also doesnt' work.

here is the code file in two formats, probably i will update my cirucit picture tomorrow.
Code :

@ DEVICE pic16F84A
define OSC 4
TrisB = %00000000

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

and in Hex:
0000- 2828 018f 008e 30ff 078e 1c03 078f 1c03
0008- 2823 3003 008d 30df 200f 2803 018d 3ee8
0010- 008c 098d 30fc 1c03 2818 078c 1803 2815
0018- 078c 0064 0f8d 2815 180c 281e 1c8c 2822
0020- 0000 2822 0008 1383 1303 1283 0064 0008
0028- 1683 0186 1283 1406 1683 1006 1283 3003
0030- 008f 30e8 2002 1006 1683 1006 1283 3003
0038- 008f 30e8 2002 282b 0063 283c


I noticed when i take off the Vss pin then the led is constantly lighting up.
if i connect Vss then nothing comes up. no power in the pins . with the multimeter i checked the pullup capacitor
is giving me 1.24 reading and no power on the pins,

what would be the problem. Is there any way of tracing this where it is going wrong?

[Archangel]

Hi Syed,
Try this code:

@ DEVICE pic16F84A
define OSC 4
PortB = 0 ' set port latches low
TrisB = %00000000 ' set portb as outputs

loop:
PORTB.0 = 1' Turn on LED connected to PORTB.0
Pause 1000 ' Delay for .5 seconds

PORTB.0 = 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

I have had the high low operators fail to work for me and I do not know why.
EDIT: Make sure to hook up that ground wire to vss pin 5

[shafi008]

I tried with the code which you gave joe. still i have the same issue.
i appreciate your patience, i am just wondering about the diagram, please check the attachement. i have tried with 2 microcontrollers. is there any way of checking the microcode programming / fault pic .

[Archangel]

Hi shafi008,
Ok this picture looks much better, I HAVE FOUND, on some low cost breadboards, the power bus strips have gaps that must be bridged. I have some like that which needed 3 jumpers to make the strips have continuity all the way across, so just for practice, please use a meter or led and check yours, just to make sure.

[shafi008]

Hi

I tried with a new bread board from radioshack. same issue.
i checked with multimeter the power from the pullup resistor to ground is giving 1.24 volts and from VDD it is 5.08. is there any way to blame this 16f84A but i am wondering if i take off the VSS then the led is constantly ligting up and the power is 0.79. i am planning to order another pic16f84a and try. i already tried with 2 pics. Is there any known institutes in Newjersey. brother if you are residing in USA, i can send it to you by post. i am trying this for the past 4 weeks to fix this... any suggestions...........Hmmmmmm

[ScaleRobotics]

When you program it with your melabs programmer, can you check the fuse settings that are shown in the programmer. I believe there is a window you can open that shows you fuse settings. Can you make sure these are set correctly. The default settings that are in picbasic should do just fine. The file it is picking these up from is in c:/pbp/16f84a.inc

You could post a screen shot of these fuse settings from your melabs programmer. What we are looking for is this window:


The meat of the 16f84a.inc file should read something like:

        __config _XT_OSC & _WDT_ON & _CP_OFF

xt osc should be right, but you might want to turn your watch dog timer off.

I would have to see if I even have a 16f84a, but you might post your hex file and I am sure someone will load it to a 16f84a and see if they get life from it.