Re: [avr-chat] avrdude: Windows COM Ports Above COM4

[Blake Leverett]

On Wednesday 14 May 2008, Richardson, Anthony wrote:
> I recently got an Arduino Decimila board and have been playing
> with it.  I'm doing development under XP.
>
> When I connected the board to the computer it was automatically
> assigned to COM10.  The Arduino IDE is able to upload
> programs to the board without any problems.  I can also
> communicate with the board using Hyperterminal on COM10.
>
> In trying to upload programs using avrdude directly however, I get
> an error.  Here is the command line I am using:
>
>   avrdude -V -F -p atmega168 -P COM10 -c stk500v1 \
>             -b 19200 -U flash:w:applet/Hello_World.hex
>
> and here is the error I get:
>
>   avrdude.exe: ser_open(): can't open device "COM10": \
>             The system cannot find the file specified.
>
> If I manually reassign the board to COM4 and just change the
> port option in the avrdude command line from COM10 to COM4,
> the upload works fine.  The Arduino IDE and Hyperterminal
> still work too and I can live with using COM4.  I would like
> to have the flexibility of using one of the higher numbered
> COM port numbers though.  My guess is that avrdude is having
> trouble using anything other than COM1-COM4 (I've only tested
> COM4 and COM10 however).  I'm a little confused because I
> thought that the Arduino IDE used avrdude (hidden underneath
> the IDE) to upload programs to the board and the IDE is able
> to upload to COM10 without any problems.
>
> I am using the avrdude that is distributed with the
> Arduino IDE (in /arduino-0011/hardware/tools/avr/bin).
>
> So, am I missing something when I try to use avrdude
> to upload over COM10?
>
> Thanks
> Tony Richardson

You can re-map to a lower COM port using the advanced button on the hardware 
dialog for the serial port.

There is an issue with Windows using comports over 9.  When opening a COM10 or 
higher port, I had to use this in a C program:

        if (port > 9)
          sprintf(str,"\\\\.\\COM%d",port);
        else
          sprintf(str,"COM%d",port);

So maybe -P \\.\COM10 would work.

Blake