I'm sending some data to the pc using attiny85 thru usb serial port. The problem resides that i do not know how to get the data and work with it, since i'm supposed to make a program in C that receives the data and send back the answer to the tiny. From google i didnt find anything (i'm probably searching the wrong keywords). Any advice, tutorials or aplication notes for a newbie would be nice so i can start understanding better about it.
I avoid C as much as possible but this Python - Arduino demo illustrates the way to do it with an Uno or Mega. The approach will be much the same using C on the PC and whatever Serial code you are using on the Attiny.
By the way I am assuming you have a USB-TTL converter between your Attiny and your PC.
If that does not help then you need to post your program so we can see what you are trying to do,