Uploading to Arduino Pro Mini

I have just received my arduino pro mini (3.3v 8mhz version) from sparkfun, along with the sparkfun FTDI 3.3v to USB breakout board.

I have connected the two together and plugged in the USB cable.

I have installed the FTDI drivers and it appears as com port 28.

I have opened the arduino software and i want to upload the simple blink sketch to test the thing is talking to the pc fine. I have changed the board type in the software to Arduino pro / pro mini 8mhz and chosen com port 28.

When I upload a sketch I get the following:

Binary sketch size: 976 bytes (of a 14336 byte maximum)

avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

I have googled this and tried everything that I've seen other people posting about this error, but still cant get the board to upload correctlty. can anyone help me??

The board needs to be reset to activate the bootloader.

That doesn't work with FTDI cables out of the box. The easiest way is to press the reset button before you press the upload in the Arduino software.

Uploading code by manually resetting the board:

If you use a USB/TTL converter with RX/TX LEDS (e.g. USB BUB board from moderndevice.com), press and hold the reset button on the board, press upload in the IDE. As soon as the LEDs flicker release the reset button. Done.

If you don't have LEDS, change this in the Arduino IDE's preferences file:

build.verbose = true upload.verbose = true

On linux the file is located in “$HOME/.arduino/”. On Windows you can find it in “/arduino-0015/lib/”. Then start the IDE from a terminal window or with “run.bat” on windows. When you press “upload”, a lot of build messages will appear in the terminal. Watch out for these lines:

avrdude: ser_open(): setting dtr avrdude: Send: 0 [30] [20] avrdude: Send: 0 [30] [20] ...

As soon as they appear release the reset button and it will upload. With just a little practice this works perfectly fine.

Thanks for your reply.

I have actually just managed to solve the issue myself.

Was a matter of setting the board to Arduino Duemilanove w/ 328' instead of the Pro Mini, as the chip on the pro mini is the 328.

Once that was selected it uploads fine and doesnt require the button to be pressed at all.

@madworm. Thank you so much for posting this info. Following your instructions I was able to resolve the upload problems with my Pro Mini. I've posted about this couple days ago, but I did not get much response. I am using an exotic serial interface card and I was able to upload sketch only once before. I guess I just got lucky pressing the reset button at the exact moment. Now I can consistently upload to the board without any issues. Thanks again!

Cheers, Nick