reasonable value of potentiometer for adc in pic

Hi,
what is the most reasonable value of potentiometer for getting adc value in pic18f2431?

hello,

i can propose :
1K , 2,2K or 4,7K
internal resistance of voltage source must be as low as possible
... ideal source of voltage generator is 0 ohms !

thanx paulfjujo, one more thing, there is also an issue that my adc is not ending its conversion in debugging i.e. ADCON0.GO doesn't clear after it has been set. I am using a loop which waits until ADCON0.GO is cleared. In some compilers it works well. Also, there is no output appearing in real hardware, can you diagnose the problem?

ADC_Acquisition
bsf ADCON0, 1 ; Start ADC Conversion
WAIT ; Wait for A/D conversion

btfsc ADCON0, 1
goto WAIT
call Update_Val
continued..............

i am initializing/configuring adc control registers in following way to get the data from AN4, single channel,8 MHz internal clock,



movlw 0x10
movwf ANSEL0
movlw 0x10 RA<3:0> as outputs
movwf TRISA

ADCON0=00000000 (later on ADCON.ADON is set)
ADCON1=00001000
ADCON2=00000011
ADCON3=0xC0

bcf ADCHS, GASEL1
bsf ADCHS, GASEL0

hello,

there is no output appearing in real hardware

Click to expand...

???
How do you test and see ADC result ?

This PIC has some special features like a FIFO on ADC
this bit (BFEMT) is read only, and FIFOEN=0 so disabled
left justified ? No delay ? FRC/4 ?
try with
Right justified, 12 TAD delay , FOSC/16

i am checking it by making port c output for ADC value. the data on port c (of adc value) is random and inconsistent with the potentiometer value (only one or two values appear for whole range of variation in potentiometer). i am making use of 8 bits of adc so left justified, i am attaching code with thread. plz review and tell me what should be the value in adc configuration/control registers for a simple single channel <AN4>, internally clocked adc. the code is working fine in proteus. proteus file is also attached.

View attachment no_int.zip