I did try turning off the USB voltage. Same result.

I was leaving PortC.5 floating when running the pulses into PortC.4 and vice versa. By tying PortC.5 low or high thru a 1K resistor the problem does go away. Interesting that i don't have to tie PortC.4 low when putting pulses into PortC.5.

Will get another pulse input set up tomorow and see if the problem goes away.

I am using a water flow sensor that counts pulses of a magnetic rotor passing a hall effect switch. Am blowing air thru the sensor to test. Am assuming you are using a push button??

The board is my own design. It is intended as a solar collector control and monitor. This is about the last bug to have it all working.

Will let you know tomorow, if having both sensors connected works.


Thanks for the help!!

RD