Uniformity of 'POT' accross pins?

[peterdeco1]

Hi Anand. I had the same problem measuring resistors. And yes, I found that portc gave me entirely different results than portb on a 16F73. The portb pins were very close but 2 of the 4 used gave me a slightly different result. So, I modified the automatic calibration program shown in the PBP manual. Perhaps you can do a similar routine to calibrate your capacitors. Scale1, scale2, scale3 and scale4 get calibrated individually and I am getting consistent results reading resistors from 470 ohms to 47K. The gosub makesound simply beeps a sounder letting you know as each scale gets calibrated. I also have a program that will beep the scale value to let you know what the actual number is. Let me know if you want that.

Clear 'ALL VARIABLES = 0
LET SCALE1 = 1 'START CALIBRATION @ 1

TEST1:
Pot PORTB.7,SCALE1,Y 'START ADVANCING SCALE UNTIL THE DEFAULT RESISTOR 47K = 253
IF (Y < 253) Then LET SCALE1 = (SCALE1 + 1): GoTo TEST1
GoSub MAKESOUND 'CALIBRATION1 COMPLETED


LET SCALE2 = 1 'START CALIBRATION @ 1

TEST2:
Pot PORTB.6,SCALE2,Y 'START ADVANCING SCALE UNTIL THE DEFAULT RESISTOR 47K = 253
IF (Y < 253) Then LET SCALE2 = (SCALE2 + 1): GoTo TEST2
GoSub MAKESOUND 'CALIBRATION2 COMPLETED

LET SCALE3 = 1 'START CALIBRATION @ 1

TEST3:
Pot PORTB.5,SCALE3,Y 'START ADVANCING SCALE UNTIL THE DEFAULT RESISTOR 47K = 253
IF (Y < 253) Then LET SCALE3 = (SCALE3 + 1): GoTo TEST3
GoSub MAKESOUND 'CALIBRATION3 COMPLETED

LET SCALE4 = 1 'START CALIBRATION @ 1

TEST4:
Pot PORTB.4,SCALE4,Y 'START ADVANCING SCALE UNTIL THE DEFAULT RESISTOR 47K = 253
IF (Y < 253) Then LET SCALE4 = (SCALE4 + 1): GoTo TEST4
GoSub MAKESOUND 'CALIBRATION4 COMPLETED