Ryan Starret

QG8 ADC Woes...

Discussion created by Ryan Starret on Jan 27, 2007
Latest reply on Jan 28, 2007 by Ryan Starret
I'm really just looking for some input...

I am using the ADC on the chip and it seems to work fine. If I hook a couple of AA batteries up to it the reading fluctuates at most +/-1 between each reading. if I attach ground to it I get a zero back every time and if I plug the demo board power into it I get 1023 steadily as well.

Problem comes in when I try to hook just about anything else up to it... I have an accelerometer from dimension engineering that when it's still it outputs 1.566-1.567V. I can watch it on the multimeter. However, these fluctuations translate into reading changes on the ADC within about 20 points of the actual reading. Just doing some quick math I found that it should fluctuate at most by 1. Same thing happens when I use an ADI Gyro. I was wondering if anyone had an insight as to how to either flatten these fluctuations (without averaging... mainly because it doesn't seem to help whatsoever) or eliminate them altogether.