مشکل در آپلود کد روی Arduino mega 2560

سلام
من از برد آردوینو مگا 2560 استفاده میکنم که البته تا امروز بدون هیچ مشکلی کد روش آپلود میکردم و ازش استفاده میکردم ولی امروز که خواستم آپلود کنم این ارور رو داد:

Arduino: 1.6.12 (Windows 7), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

Sketch uses 66,524 bytes (26%) of program storage space. Maximum is 253,952 bytes.
Global variables use 2,917 bytes (35%) of dynamic memory, leaving 5,275 bytes for local variables. Maximum is 8,192 bytes.
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
An error occurred while uploading the sketch

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