If you are looking for;

  • How to program Arduino Mini Pro with CP2102 USB-to-TTL serial converter 5 pins without DTR (reset pin)
  • How to program Arduino Mini Pro without using Arduino board as ISP

This post probably will help you.


  1. Arduino Mini Pro (In this example I’m using Arduino Mini Pro 5v / 16Mhz version)
  2. CP2102 USB-to-TTL (Drivers for Mac, Windows, Linux or more..)

    USB view in system
    USB view in system

Connections CP2102 USB-to-TTL 5pins to Arduino Mini Pro:

  1. CP2102 USB-to-TTL: TXD (green) -> Arduino Mini Pro RX
  2. CP2102 USB-to-TTL: RXD (yellow) -> Arduino Mini Pro TX
  3. CP2102 USB-to-TTL: GND (brown) -> Arduino Mini Pro GND
  4. CP2102 USB-to-TTL: +5V (red) -> Arduino Mini Pro VCC

Uploading Sketch with Arduino IDE

I’m currently using Arduino 1.5.5. I configured it as below;

  1. Arduino IDE -> Tools -> Board -> Arduino Pro or Pro Mini
  2. Arduino IDE -> Tools -> Processor -> ATmega328 (5V, 16 MHz)
  3. Arduino IDE -> Tools -> Port -> /dev/tty.SLAB_USBtoUART
  4. Arduino IDE -> Tools -> Programmer -> AVRISP mkII
  • /dev/tty.SLAB_USBtoUART is the name of serial port shown on Mac OS X. On windows you should see comX (X is a number)
  • To find serial port name list, write on terminal;

The CP2102 USB-to-TTL hasn’t 6th pin for auto reset Arduino board so you have to click on reset button on Arduino Mini Pro manually.

  • Click on upload sketch (green right arrow)
  • As soon as you see “Compiling sketch…” on status bar, click on reset button.
  • If your timing is good you’ll see “Done uploading.”

Boards that I’ve used.