Interface microcontroller with bluetooth device(SPP)

I assume the HCS08 has an integrated UART. If so, you need to set up the UART for the correct communication parameters (baud rate, No of bits, Parity etc.) The manual of the HCS08 should give you the necessary information.

You may also need an RS232 level shifter. That depends on the interface of the bluetooth module. The HCS08 will operate on 5V or 3.3V, I don't know. RS232, however, uses +-12 V. Unless the bluetooth module uses the UART protocol but a logic level (5V or 3.3V) that is compatible with the HCS08. Again: read the manual.

What do you mean by RS232 format? RS232 describes the physical data format but not the way the transmitted information is to be interpreted. This has to be defined by the user. Normally the UART will transmit and receive single bytes (8 bit). The meaning of these bytes is entirely controlled by your application (such as e.g. sending AT commands as a series of appropriate bytes). What you have to send and how you have to interpret the received data from the bluetooth module should be described in the module's manual.

Harald