I am working on a project that requires me to use an ATtiny microcontroller with bluetooth module HC-05. I have used the module with Atmega 8 in the past using UART protocol. Can anyone help me in using this module with ATtiny 45/85. PS: I have no idea about programming arduino, and use embedded C language for my projects.
I assume that you wish to implement a "soft" UART on the ATtinyx5 because they do not have a hardware UART. If this is NOT what you want, please provide more detail.
A UART is relatively easy to implement in software. If you can dedicate the main focus of the program to the UART so timing can be implemented with delays it is quite straight forward. If you have other tasks that occupy significant processor time then use of interrupts helps simplify code. Fortunately, a number of people have already implemented ATtinyx5 UART code and there is a range to choose from.
Here from 'Garagelab" is what looks like it may be an excellent x5 capable UART as part of a library of other x5 routines.
Here is code for a receive only UART for ATtiny85
This search is liable to be useful.