how to send signal (Logic high) to PIC microcontroller?do i need any interfacing that connect the signal ranging from 3-5V to PIC pins,such as the PIC may need special interfacing technique?or i can directly feed the 3-5V output to the PIC?

It would be as simple as a wire to a +5V supply. Just like with any other chip.... the difference you program what happens when there is such a signal instead of having say just a AND gate all the time.

What are you doing?

Ivancho

i am dealing with a RF remote control toy car.i want to use the output voltages from the receiver side and interface it to the PIC.the output voltages of the receiver are ranging from 6-8V.the questions are:

i want to use 7805 regulator to step down the voltage to 5V only.can it be done with the 7805 regulator?how much input voltage should be fed to 7805 so that it will maintain its output at 5V? (i am poor in reading the data sheet,sorry).

are CMOS and TTL compatible with each other?

can anyone help me?

The input to the PIC is fairly high impedance, you can probably just attenuate the signal with a voltage divider to acheive a safe level for the PIC.

From the datasheet:

http://www.onsemi.com/pub/Collateral/MC78L00A-D.PDF

NOTE: THIS IS A PDF DOCUMENT
(I hate when websites don't tell you this and you click on it and it takes forever to open in your browser. If I want to read a PDF I right click on it and "Save As", sorry, end of rant! )

"The input voltage must remain typically 2.0 V above the output voltage even during the low point on the input ripple voltage."

You only have to read the first page or two to get a good idea how to use the 7805, and Onsemi is really good about sending out samples really fast!

D

I've done this very thing. Just power the reciever with 5v.