Newbie with Micro Pro upload problems

Occasionally upload works OK but usually it fails with the message: avrdude: error: buffered memory access not supported. Maybe it isn't a butterfly/AVR109 but a AVR910 device? I have not managed to find out yest what is different when the upload works. Once the program is uploaded the program itself functions perfectly.

I tried a USB 2.0 port on the front of my desktop and one on the back. My OS is Windows 8.1 64 bit and IDE is Arduino 1.05-r2

Before discovering this forum I posted at but got no reply.

I have had a look at the troubleshooting guide but have not managed to figure it out. I am familiar with software generally but am new to Arduino and am not skilled with hardware.

Could it be the Micro Pro is not in "programming mode" and if so how do I put the Micro Pro into programming mode? If not any other clues as to the meaning of the error or what diagnostics to look at would be welcome.



Morning Geoff,

that's normal. This question apparently is ignored by those who know the answer... I am not sure about the motivation of not giving the answer... maybe some "let him struggle" attitude? ]:)

However, here is an answer: the micro has the USB and the serial interface in one chip, the 32u4. Windows (no matter which) can only see the USB device, but cannot see the bootloader and the serial access which is hiding behind the USB device (playing hide and seek with Windows). You need access to the bootloader and you will be able to access it after some "dirty" trick ]:D

  • "Glue" a reset button (or some possibility to pull low the RST pad of the PCB).
  • Open your Windows device manager and unfold the entry "COM & LPT"
  • Find there listed your Arduino which is either "ProMicro" or "Leonardo" (I am using the Leonardo drivers and it works), depending on as what you installed your Ardu.
  • Now double-press the reset button (single press will offer only 3/4sec which not enough, double-press will offer 8 seconds which is not much either but, enough least after some tries for traing :D )
  • Whatch the device manager, there will appear an unknown device,
  • rightclick it to (re)install its driver. Choose "Select device from a list", select from the left column "Arduino..." and from the right column "Leronardo" resp. "SparkFun ProMicro 5V/16MHz" (except you have the 3V3-type, then of course select that one). You may not be lucky being fast enough to accomplish it within the 8 seconds at the first time. But, be patient, you will get faster ;)
  • After the installation was successful, open your Arduino IDE, goto tab "Tools" and select "Serial Port" and find there the port that Windows did choose for the USB device, lets assume this is COM9. This is not the one you need! The one you need appears only after double-pressing the RESET button again. So...
  • Double-press RESET, go to the "Tools" tab, select "Serial Port" and see there a COM10 being available underneath the entry of COM9 which is still there (and probably checkmarked). Hint: the COM port of interest is usually one number higher than the COM port of the USB-device that Windows is seeing by default.

  • Checkmark the COM10 instead!!

You're done! Upload your sketch and be happy :) Sometimes the IDE looses this port and therefore refuses to upload something. In this case, pull the ProMicro from the USB-port, wait for the USB-out sound, plug it back in, open "Tools/Serial Port" and you should see there the correct COM being present and checked. If this doesnt help, you have to close the IDE and reopen it again.

This hassle is not self-evident!! Especially not for a beginner!! I struggled with it also... :astonished:

Make sure you're using Arduino 1.0.5-r2 and not the newer beta versions (like 1.5.6-beta), they do not work here... yet! Maybe you also wanna checkout these postings of mine where I documented my struggle and efforts to get this working, click

I hope this was helpful ;)

Cheers okdi ;)