Cannot upload sketch to DFRduino nano
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I previously succeed in uploading the code to DFRDuino Nano (Arduino Nano Compatible) (with wrong digital pins) but after changing pin I cannot upload it again.
From the [document][1], I changed back the pins 0 (RX) and 1 (TX) are used for serial communication.
In arduino ide (1.8.19), I choosed **board: Arduino Nano** and **Processor: ATmega328P(Old Bootloader)**
The error:
```
…
avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
System wide configuration file is "C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.57.0_x86__mdqgnx93n4wtt\hardware\tools\avr/etc/avrdude.conf"
Using Port : COM3
Using Programmer : arduino
Overriding Baud Rate : 57600
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00
avrdude done. Thank you.
An error occurred while uploading the sketch
```
I have reset both the board and computer but without luck.
Any idea how to solve it ?
[1]: https://wiki.dfrobot.com/Arduino_Nano_328__SKU__DFR0010_
I found if you select TOOLS>Processor>"old bootloader" seems to work. Strangely I only have this problem on some nanos others are fine. Guess that is just the chip selection they use.
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Hi, When a device is connected to the TXRX interface, the upload will fail due to a communication conflict. Please upload code first and then connect TXRX
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