Program Arduino Pro Mini Using Arduino Uno




Introduction: Program Arduino Pro Mini Using Arduino Uno

Hello everyone. Today I am going to show how to program arduino pro mini using arduino uno.

If you already had a arduino uno and you newly buy arduino pro mini then you don’t need to buy the USB to serial converter to program the arduino pro mini because you can program pro mini using your arduino uno board. We can make pro mini to act as a central ic for arduino uno board. First of all you have to know which arduino pro mini you are using either it is 5v 16mhz or 3.3v 8mhz. Use only 5 Volt and 16MHZ pro mini with the arduino uno. we can't program 3.3v 8mhz pro mini with arduino uno. Here i am using 5v 16mhz pro mini.Let us see the circuit connection.

Step 1: Video

Instead of reading you can watch video for full description

Step 2: Connect Pro Mini With Arduino Uno

Follow the simple steps bellow: the circuit connection
clearly shown in the video

Remove the ic in arduino uno board.

  • Connect arduino uno board 5V pin to pro mini’s VCC pin.
  • Connect arduino uno board GND pin to pro mini’s GND pin.
  • Connect arduino uno board TX pin to pro mini’s TX0 pin.
  • Connect arduino uno board RX pin to pro mini’s RXI pin
  • Connect arduino uno board RESET pin to pro mini’s RST pin.

Step 3: Open Arduino Software for Program the Pro Mini

Connect the all circuit connection now open the arduino software and select tools->Board ->Ardunio Pro or Pro Mini(5V, 16MHZ) vv/ ATmega328. if you select the arduino pro you can see the selected board in the bottom of the software as shown in above image.

And open the coding you want to program and click the upload button. Now you can see that program uploading into pro mini. you can see the tx and rx led in arduino uno board blinking while program uploading . after uploading of the code. now remove the all connection and give power supply to the pro mini. your code works perfectly on arduino mini. enjoy projects with pro mini. watch the video for to clearly see how to do all steps.

Thank you for reading.

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17 Discussions

Slight correction - you can use either the Pro Mini 5V or 3.3V, both will work. The 3.3V version can accept Vcc input of up to 12V, and thus powering it off of the Uno's 5V is not an issue. Just make sure that you select the 3.3V, 8MHz version in the Arduino IDE, otherwise your timing will be screwed up (delays will be twice as long as the code will be translated to a board with twice the clock speed).

1 reply

small addition - the wiring is the same if you use a 3.3V Pro Mini, you don't need to use SPI as was earlier posted.

in arduino IDE tools->programmer->?? what we have to select.


TX - TX,

RX - RX,

5V of Nano to VCC of Mini

GND of Nano to GND of Mini

RST of Nano to GND of Mini.<-----------------

I uploaded sketch from Nano to Mini Pro. Hope the sketch is uploaded to Mini and not to Nano. I seen the TX-RX LEDs blinking.


TX - TX,

RX - RX,

5V of Nano to VCC of Mini

GND of Nano to GND of Mini

RST of Nano to RST of Mini.

Then without pressing any buttons clicked upload in Arduino software.

A slightly different configuration worked for me:

Pro Mini ----- Uno

GRN-------- Reset

VCC ------- 5V

GND -------GND

RX -------RX


Thanks a lot.. i tested with pro-mini..(5V version) ... it worked. !!! Can i also be able to program a nano using an uno in the same way..?

No because you have to remove the Atmel ATMega Chip and u can't remove it from arduino nano

Awesome Project , really nice

check this one out :

Hello please

I want someone design for me from A to Z Arduino sketch ?


As mentioned, easier to plug in usb ftdi or similar to the pro mini.
No need to mess about removing the chip from the uno board.. If you can as some clones use surface mount chips.
If you must save yourself £1.50, look into arduino as isp. No need to remove the chip and you can upload without the bootloader too.

Can i just simply use the programming code from Arduino Pro Mini into my Arduino Uno without using Arduino Pro Mini?

The 3.3v version of the Pro Mini CAN be programmed from an Uno using SPI - see this article for a guide -

You can using a dumilanove too ^^.

This can work with other bord who are in 5v 16mhz.

1 reply

This will certainly work, but one has to keep pulling out the Atmega from the UNO. If u need to do a lot of programming, safer to get a USB-TTL adapter for around 1.50 euro that will fit the header of the Pro mini exactly