I'm trying to program and debug my MC9S08GT16 on my personal PC in serial monitor mode but it gives me a connection error message saying 'communication cannot be established because the target does not respond to communication requests'. What should I do for monitor mode and BDM? Any sort of help would be appreciated.
I recommend you the Application Note AN2140 in order to help you with your issue.
This application note describes a 1-Kbyte monitor program for the MC9S08GB60 MCU. This program supports 19 primitive debug commands to allow FLASH programming and debug through an RS-232 serial interface to a personal computer. This monitor supports primitive commands to reset the target MCU, read or modify memory (including FLASH memory), read or modify CPU registers, go, halt, or trace single instructions.
Please find the Application Note mentioned above in the next link:
Make sure you download the associated files too.
Hope this information will be useful for you.