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Posted: **Mon Jun 10, 2019 12:51 am**

This is something that I wanted to ask earlier.

I have these Chinese Arduino clones, with ch340 chips.
If I use the hardware UART, I can't flash the Arduino while the RX is connected to a device..

I need to disconnect the RX pin before I can flash the chip.
Is there a way that I can flash it without disconnect the RX pin?

Thanks!

Posted: **Mon Jun 10, 2019 8:25 am**

No, if you have a signal holding the RX pin and interfering with the signal from the ch340 chip, then it will stop the bootloader from receiving.
Resistors and diodes might help. Arduino forums might have some suggestions on this.

Posted: **Mon Jun 10, 2019 8:56 am**

You can use ISP (or ICSP) to program the Arduino. This bypasses the bootloader altogether and is useful in cases like this, for programming chips without usb access and adding the bootloader to be chips etc..

Search the Arduino forums for details

Posted: **Tue Jun 11, 2019 3:22 pm**

Thank you all!

Matrix user forums

Flash Arduino with RX from UART connected??

Flash Arduino with RX from UART connected??

Re: Flash Arduino with RX from UART connected??

Re: Flash Arduino with RX from UART connected??

Re: Flash Arduino with RX from UART connected??