Maximum allowable TTL input voltage

Hello there.

I am doing a final year university project and I need to read a voltage from a sensor into a microcontroller. The output signal from the sensor will be read in to the the microcontroller through a port set up to read inputs.

The sensor output is 12volts, what I want to know is will inputting 12volts into a 5volt ttl logic pin fry my chip, so to speak.

Thanks for any responses.

Steve

 

Do you think you could elabourate slightly? Its slightly unclear what exactly you are doing. Is it into a serial port, or paralell port, or into a completley independant unit? What does the sensor read, and can you not get a compatible sensor for the chip/whatever?

I probably personally cannot be of much use, but I'm sure expanding slightly on your problem will allow some other people to help you

 

Yes it will. Do not apply +12V to a TTL level input!

You will need to use a 5V sensor, or reduce that sensor output to 4V ~ 5V, perhaps with a zener diode?

 

Thanks for your replies, thinking about it I may be able to get round it by using a potential divider to reduce the voltage down to a safe level.