为了测试代码执行到哪写了serial.print("5"),结果现在烧入不了

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00上传失败: 上传错误：exit status 1

测试完发现不是程序的问题，可能是烧写口坏了，线和电脑都换过了

大概率烧写口坏了，日

完了，我今天也是这个问题，让另一块板子用ISP也写不进去

按住boot可以强制进入下载模式，所以当死循环造成无响应，可以一直按住BOOT直到新的程序烧录完成。