16F877 Flickering LED

[koossa]

Here is my code:




Include "Modedefs.bas"

DEFINE OSC 20 ' Set the Xtal frequency to 20mHz
RFVDDPin VaR PORTA.3 ' RF Module Power Pin.

Main:
ADCON1 = 7 ' Set Analog pins to Digital.
TRISA = 0 ' Set all PortA Pins as output
high RFVDDPin ' Switch RF Module On.
end

[koossa]

What is looking weird about my circuit?

[mister_e]

by using end this make your pic to stop or goto lalaland IMHO.

what about

DEFINE OSC 20 ' Set the Xtal frequency to 20mHz

ADCON1 = 7 ' Set Analog pins to Digital.
TRISA = 0 ' Set all PortA Pins as output
RFVDDPin VaR PORTA.3 ' RF Module Power Pin.


Main:
    high RFVDDPin ' Switch RF Module On.
here:
     goto here

also be sure you set the oscillator configuration fuse to HS.

[koossa]

"also be sure you set the oscillator configuration fuse to HS."

How do I do this?

[mister_e]

in your PIC programmer software or into your code
click here to know set fuse into your code

be sure you have a PIC who can handle the 20Mhz clock. PIC16F877-20

[koossa]

Is _XT_OSC for a Crystal, because that is what I am using and that is what the Inc file's default is?

[mister_e]

XT_OSC is used for 4MHZ crystal/oscillator speed. HS_OSC is used for crystal/oscillator over 4MHZ. The default setting is XT_OSC. There's no difference for a PIC to see ceramic resonator or crystal... since it generate pulses.

So in your case you'll have to change it to HS, in the .INC file or as i suggest, comment the config lines in your .INC file and place all fuses setting in your code. Really handy.

[koossa]

Hi Steve

I have done the following:
Edit C:\pbp\16F877.INC, Replace _XT_OSC to _HS_OSC

And edit my code as followings:


Include "Modedefs.bas"

DEFINE OSC 20 ' Set the Xtal frequency to 20mHz
RFVDDPin VaR PORTA.3 ' RF Module Power Pin.

Main:
ADCON1 = 7 ' Set Analog pins to Digital.
TRISA = 0 ' Set all PortA Pins as output
high RFVDDPin ' Switch RF Module On.
here:
goto here
end



But with no luck, it is still flickering?