i want to upload sketch into arduino uno using usb/ttl adapter.i tried searching for it, but found about programming arduino using another. can anyone help me.

  • This may be obvious to you, but may not be to us. What are you connecting to each end of the USB to TTL adapter cable?
    – st2000
    Aug 4 '17 at 11:58
  • 1
    I'm trying to understand your question, why can't you just program it by plugging a USB lead between a PC and the board. Are you doing something special? Aug 4 '17 at 12:56

The Arduino onboard USB to serial is connected to D0 (Rx) and D1 (Tx).

And without a USB connected to the Arduino you can use a USB/TTL adapter connected to D0 and D1 like this;

Arduino  - USB/TTL
Tx       - Rx
Rx       - Tx

And to get the Arduino inte "programming" mode:

  • Automatic way, if the USB/TTL have CTS, connect it to Arduinos reset pin.
  • Manual way, press the reset button when the Arduino IDE starts to upload the code.

The Uno is normally programmed by its on-board USB adapter.

The Pro Mini does not have an on-board adapter, and is normally programmed with an external USB/serial adapter. This should also be possible with Uno.

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