My sketch won't load when external powering Nano

Hi !

I have an arduino Nano and I made a program using Mirf. It's working great when plugged to my computer, but I can't get it working on external power, unless I press the reset button. Once I pressed the reset button, everything is working fine, but it's not what I want. I want it to work on external power source without pressing the reset button.

I did some search on this forum and I found that one chip seems to have this problem (Diecimila) but I'm wokring with a Nano thing.

Anyway I tried to connect RX and TX directly as mentionned in the link, it's not working.

Any help ?

Thank you :)

Hi, welcome to the forum.

The troubleshooting for the Arduino Diecimila is not for the Arduino Nano. The Arduino Nano has a normal reset circuit.
We need to know a lot more. How is everything connected ? What kind of power supply do you use ? To which pin do you connect the power supply ?

If you remove everything from the Arduino Nano, and upload a sketch for a blinking led. Will it blink when you use the power supply ?


Thank you for your answer.

I'm connecting the power supply to Vin and the GND next to it. My power supply is a 12V 1A

I plugged a nRF24L01P like that : Pin D10 : IRQ Pin D12 : MISO Pin D11 : MOSI Pin D13 : SCK Pin D9 : CSN Pin D8 : CE + GND and 3.3V (next to D13)

I tried with a blink program, and it blinked =( How is that possible ? My program is just a Mirf example (ping client/server)

Thanks !

Use a different pin for the IRQ. Pin 10 is connected to the SPI hardware inside the ATmega328p. The Nano is the only board with a weak 3.3V. I don't know if it is enough to power the nRF24L01+. The usb might fail if it doesn't have enough power for the nRF24L01+.

Do you have another Arduino board ?

Hi !

Thank you for your help.

I'm a bit lost. I tried on another nano board I have and everything is running smooth when I power it from external source.

Is my first arduino nano dead ? Is there an explanation ?

I think the first one is broken. I have no explanation.

The Arduino Nano has weak 3.3V output, so I cheched the datasheets. It turned out that it is not a problem at all. Arduino Nano 3.3V supplied by FTDI (FT232) chip: 50mA. nRF24L01+ supply current: 10..15mA