“上载草图时出错”Arduino

我正在学习从Arduino的UART引脚接收数据。我使用的是同一规格的气体传感器。这是我能写的最简单的代码。

void setup() {
  Serial.begin(9600);
}

void loop() {
  if(Serial.available()>0) {
    Serial.print(Serial.available());
  }
}

代码进行了验证,但当我试图在Arduino Uno中烧录此代码时,在它说代码使用了5%的存储空间后,我得到了以下错误。

Sketch uses 1744 bytes (5%) of program storage space. Maximum is 32256 bytes.
Global variables use 184 bytes (8%) of dynamic memory, leaving 1864 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x1e
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x66
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x7e
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x06
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x86
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xf8
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x06
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x7e
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x86
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x9e
An error occurred while uploading the sketch

请帮忙。