I want to us use an Analog input pin on an AVR to read a voltage from 0 to 30 volts.
I'm thinking I will divide the incoming voltage equally 6 times to give me 0-5 volts to connect to the pin, then use the software to multiply the value by 6.
To figure the values of the resistors I need to know the input impedance of the analog pin as this will be seen as a resistance in parallel to the divider.
I looked through the 300+ page data sheet but didn't see any min/max values for the pin - but I could have missed it.
Anyone know the input impedance of the analog pins - or is there a better way to do this?