hey....!
i am using mega 2560, when i connect a 12V-1Amp external power supply , i can'nt access the serial or it does not show the serial port for board.
Please help me...
Do you use the DC jack plug for 12V ?
There are few possibilities:
1 ) The board could be broken. Perhaps the voltage regulator is blown by reverse current. Or you have a bad soldered clone from Ebay. Or you applied 12V accidently somewhere on the Arduino board.
2 ) The voltage regulator reduces the output if it gets too hot. If you use the Arduino board to power a lot of things (like leds) the voltage regulator might get hot. The higher the input voltage, the hotter it gets.
daani:
hey....!
i am using mega 2560, when i connect a 12V-1Amp external power supply , i can'nt access the serial or it does not show the serial port for board.
Please help me...
Have you measured the voltages on the Arduino when it's connected?
It would be better to use a 9V external ps because the 12V is forcing the mega onboard regulator to dissipate a lot of extra heat.