help using adcin

[Dave]

F1CHF, The probable reason for the A/D reading jumping around is the input has some noise on it and it is being digitized. With a 5 volt reference for the A/D the minimum resolution per bit is 4.9 Millivolts. You should either do some kind of analog filtering using an RC network or do some kind of software filtering. The A/D is only telling you what it sees. Also make sure you have a ROCK stable reference voltage at the PIC. If you have access to a scope, use it, you will be supprised at what you see...

Dave Purola,
N8NTA

[F1CHF]

Sir ... you got it !
I use to "play" with a homemade dev board with a lot of stuff things
like LCD, switches, push button, led, In situ prog, etc ...
this developpement board is OK for normal use.
In this case .. I discover that the small power supply has a 0.120 volt
ripple .. with some spikes !
2200 µF on the power itself, the well know trio of decoupling capacitors
near the +5 volts regulator, and also near VCC and VDD on the PIC !
you got it !
I have forgotten the basic rule of electronic .. have a CLEAN power supply!
it was clean for basic opération since 5 years ! not for analogique use !
you are the winner !

I am working on the following project :
Using an On Screen Display IC (STV5730) show the antenna rotor position
used in a radio amateur TVA repeater.
I need to find a very good potentiometer to avoid variations in the reading
thanks a lot 73's from F1CHF

[harryweb]

Bonjour CHF,

J'ai essayé avec ta méthode, sans succès.... bon c'était de la simulation et ce prg fonctionne (en simul) sur pic16f88, pic16f87x.... je vais essayer avec un vrai 18f1220.

Mais j'y pense, f1chf.... ne nous connaissons nous pas ? ce call me rappelle qq chose... du temps ou je faisais de l'émission OM et de la TVA... mon ex call F1SLU herve (pres de melun)

73's