optoisolators

[Foaad]

I put the signal through two inverters and now its a perfect square
wave but somehow the voltage became 5.12V instead of the previous
4.88V so i sticked in a 120K resistor and now the voltage is back to
4.9V
You think its safe to use this as an input to the microcontroller?

 

[James Beck]

I put the signal through two inverters and now its a perfect square
wave but somehow the voltage became 5.12V instead of the previous
4.88V so i sticked in a 120K resistor and now the voltage is back to
4.9V
You think its safe to use this as an input to the microcontroller?

The only way the signal could become 5.12V after the inverters is if you
are powering the inverters from a voltage of at least 5.12V. If the
inverters are running off the same power as the MCU you shouldn't have
any problems, BUT you still need to make sure you take care of the other
issues mentioned in earlier posts. Working now does not mean working
later. Sticking a resistor in line with the signal is not a good ideas
BTW.

Jim