View Full Version : 18F2525 ADC Accuracy
mungam753
- 28th December 2005, 02:57
I am seeing a number jump of 144 to 155 on my analog conversions of 5VDC with a 740 millivolt input. I don't see the input changing but the conversion seems to be not as accurate as I would like it to be. I am using a 10 bit result and a 4mhz crystal.
Is this normal or do I have some settings hosed up?
Bruce
- 29th December 2005, 03:49
It's very normal to see AD values jump if you're not using a filter circuit on the input.
Try a filter something like this;
AD input
o-----/\/\/\/\---1K--- external analog input
|---| |---0.1uF---gnd
There are other simple tricks like using sleep mode, and filters on Vref for noisy power rails.
mungam753
- 29th December 2005, 04:48
I am testing right now and it seems to have cut the jumping around in half. I thank you for your help as this has been driving my nuts for the last week.
Powered by vBulletin® Version 4.1.7 Copyright © 2025 vBulletin Solutions, Inc. All rights reserved.