The Arduino Pro Mini is a great microcontroller board based on the ATmega328. The board comes without built-in USB circuitry, so an off-board USB-to-TTL serial convertor must be used to upload sketches. This can be a FTDI TTL-232R USB – TTL Level Serial Converter Cable for the 5V Arduino Mini Pro), or a FTDI TTL-232R-3V3 USB – TTL Level Serial Converter Cable.
In this post we will see how to upload sketches to the Arduino Pro Mini using an Arduino Uno.
Remove the ATmega328 microcontroller from the Arduino Uno Board.
We’re going to use the following pins to connect to the Arduino Uno.
Pro Mini -> Arduino
DTR to Reset
TXD to TX
RXD to RX
VCC to 5V
GND to GND
Make the following changes in the Arduino IDE
Compile and upload your sketches