hi everybody again,
I'm dealing with a design here, where a CAN AVR is powered from 5V, and I have to measure signals varying from 0V to 6V.
I don't need to measure once it is above 5V. The only information I need is voltage when it's from 0V to 5V or if it is above 5V.
Before using a zener to limit input voltage, I thought it might be possible to use the AVR's internal protection diodes to do the limiting. Maybe 4.7k series resistor between input voltage (which is low impedance) and AVR's AD pin.
Of course this probably isn't the best way, but I would like to know if anyone did something similar for a design.
On the other hand, the closest zener I found is 5.1V, which may help, but according to the datasheet the AVR will tolerate up to VCC+0.5V only.. maybe powering a little bit above, like 5.3V, may do.
thanks in advance,