ft232rq to mega328pau

Dear all, I’m new to the forum, but is quite a bit that I’m working with arduino to make some projects. Now I find myelf in trouble because I made a pcb based on atmega328pau (with bootloader) and a ft232rq that i would like to use to program the mcu. Here comes the problem, when I connect the pcb to the pc and open arduino IDE i can find the com port but when i try to upload the sketch the only thing i can get is avrdude telling me “not in sync: resp=0xf1”. Not getting the result i wanted I’ve started testing it deeply:

  • reinstalling FTDI driver → nothing has changed
  • changing selected board to nano/pro mini/uno → nothing has changed
  • changing baud rate in the com driver, but as i saw in the verbose output avrdude ovverides it → nothing has changed
  • checked the pcb circuit with sparkfun similar board → seems ok (attached the schematics)
    Perhaps is ft232rq that needs some programming? I’m running out of ideas right now, maybe someone would kindly be able to help me. Thanks

The FT232RQ need not programming. It should work by default as you need. It looks like FT232 works properly so reinstalling driver and similar action does not help.
Are you sure ATmega has bootloader? You can be sure only with ISP programmer to readout FLASH boot region. Better to replace it with known version. Do not forget for fuses. You will need ISP pins wired out.
Changing the baud rate: The baud rate is fixed and defined by the bootloader (set during make process). Usually it is 115200baud.
Selected board: Yes, it can cause the error like this if wrong type is selected.
Circuit: After brief look seems to be OK. However, I am always recommending to start with minimum of parts. (I have some personal experience with self made boards.)

Thanks for the quick reply, I will explain better my situation, I desoldered an atmega328pau from an Arduino pro mini that had the bootloader already. I changed the board in Arduino IDE because selecting different one make avrdude to change the baudrate for the programming.

Just looked at the schematic you posted a pic of, and not sure if this has anything to do with your problem, but are you missing the ferrite bead as per the datasheet for the ft232r?

Here's a link to a pic of a USB2Serial converter a friend of mine said I could share (screenshot from in his eagle software) in another discussion here, so I suppose I can share it with you. Your problem could be something else, but this is just something I noticed looking at the pic you provided. Here is the link.

Not sure if it even needs the bead, I'd have to ask my friend, or look closer at the datasheet. A bead usually gets rid of high frequency noise which can find it's way through a switching power supply especially. Maybe try an "old heavy" power supply (less noise) before looking much further into the bead, or maybe look at it with a scope?