AVR-Chat

At 06:57 PM 6/22/2004 +0000, p_anglum wrote:

>I'm using a Tiny 15 to convert a 0-10 volt input to PWM output.
>I use a voltage divider (10K - 10K) to scale the 0-10 down to 0-5 
>before applying it to PB3(ADC3).
>
>Everything seems to work except at the lowest range of input voltage 
>the A/D seems to always read some small voltage.  In fact, with my 0-
>10V input removed and only the voltage divider on the input to to 
>ADC3 I read about .9 volts on ADC3.  It appears the source of the 
>voltage is the ADC3 pin itself.  Any ideas?
>(All voltage measurements were made in refernce to pin4 - GND on the 
>Tiny15)

You may have too high an input impedance. 
Also, what's your reference voltage? On the Tiny-26's, the 2.5V "precision" reference comes out at 2.7V.