[PIC] PIC18F4550 ADC sampling frequency

[patelvivekv1993]

i am having trouble understanding the ADC module of PIC18F4550
i have configured it as follows
clock 20MHz
PLL prescaler divide by 5

System post scaler
96Mhz/6

Hence my Fosc = 16MHz
now i selected Tad = 16Tosc(101)
also Tacq = 4Tad
hence by adding above two i will get 5us which means sampling frequency is 200KHz?????

and if my sampling frequency is 200KHz(5us) then if i input a square wave of 2KHz(500us) then i think for one cycle of square wave i must get 100samples in which 50samples with 5 and 50 samples with 0??

but it is not happing....
i am using proteus for simulation...

 

[wp100]

Hi,

The ADC input is for measuring an Analogue signal.
This tutorial might help is you are using C


To measure the frequency of a square wave you use the CCP Capture Compare module.
https://ww1.microchip.com/downloads/en/DeviceDoc/ccpwm.pdf

 

[patelvivekv1993]

Hi,
thnx for the tutorial link...
i just wanted to know that whether my adc is working at the sampling rate which i have calculated......bcuaz this is the initial phase then i want to make a PLL using dsPIC...i know its pretty much big step but i wanted to go..by taking small steps...so if by any means we can know at which frequency it practically runs..then it would be helpful to debug in my future application...so is there any way??