[avrdude-dev] avrdude, problems on Mac OS X

[Christian Prinoth]

Hi,
 I am currently using avrdude 5.10 on Snow Leopard with a mySmartUSB MK2
programmer, which I understand is avr910 compatible.
I installed the Silabs driver and the device shows up as
/dev/cu.SLAB_USBtoUART.

Now if I execute:
  avrdude -P /dev/cu.SLAB_USBtoUART -c avr910 -p m8
everything works, so no problems. But if I do it a second time, I get
  avrdude: avr910_recv(): programmer is not responding

The only ways to getting everything to work again is either unplug/replug
the programmer, or run "screen /dev/cu.SLAB_USBtoUART 19200", which probably
somehow resets the serial port and makes the programmer accessible again.

I have tried the same setup on Ubuntu in a Virtual Box inside my Mac, and
there everything works perfectly, so there must be something wrong with how
avrdude handles the mac serial port. Does anyone have any suggestions on how
to fix this? It is not a big issue, but annoying nonetheless.

BTW, I have tried debugging avrdude to find out what is happening, but my
understanding of serial port protocols is too limited to be useful.
Nonetheless, any hints of what I should look for in a debug session are very
welcome as well. For example, if this is an issue of correctly closing the
serial port, what piece of the code should I be looking at? Does anyone know
of differences between Linux and OSX in how serial ports are managed?

Thanks
Christian