--- In AVR-Chat@yahoogroups.com, "Dave McLaughlin" <dave_mclaughlin@...> wrote: > I would put a 5.1V zener diode across the input to the AVR ADC If you do so, you must be careful to select a size for the upper resistor in the divider so that the current is limited to a safe level for the zener. Most modern AVRs do have clamping diodes to Vcc and ground on all I/O pins but you can add an external clamping diode (instead of the zener). The external diode should have a forward voltage lower than 0.5V since that appears to be the forward voltage of the internal clamping diodes. Here, again, the upper resistor in the divider must be large enough to limit the current to a safe level for the clamping diodes. Don Kinzer ZBasic Microcontrollers http://www.zbasic.net
Message
Re: Butterfly mod
2009-08-12 by Don Kinzer