it has happend in the end. i've transformed my arduino in a nice useless brick.
i was playing around with motors, and it stopped working.
then decided not to load any new sketch
this is the error:
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
now a bit more.
the pin that i was using in pwm seems to be always output low.
when i start uploading the rx led is blinking faintly.
no 13 led lights, also when reset button pressed.
shall i order a new atmega chip or the whole board?
well i'm not sure that reburning the bootloader will be enought.
someone has ideas?
thanks.
Giovanni
you probably just burned out the chip, its generally not a wise idea to run motors (or much of anything) directly from the arduino pins due to the fact that it does not have much current that can pass tru it
you can remove the chip and install a jumper wire in the chip socket tween pins 1 and 2, when you send data out of your pc to the arduino that wire should loop the same data back to the ftdi chip and pc, If you want to check
i know that's not normally a good idea, that's why i was using a darlington transistor and using the vin pin and not the 5v one... but... i just don't know what happened....
but thanks for the idea of shortcutting to test usb to serial chip....
ohh... that's nice... well...
the board seems to work.
at least the trick worked, pretty amazing...
but i still want to know what happened...
i did only two thing that i'm not sure were correct:
-programmed it while on external power supply.
-no loopback diode in the driving motor cirquit. but i was using npn darlington (in the scheme it seemd to have inside a diode to keep the transistor safe).
what should i avoid next time?