USB to Serial Converter using AVR microcontroller


This project is a USB to Serial converter using an ATMEL AVR microcontroller. There are two version of the converter, one with SMD parts and another with TH parts. The mcu used is an ATmega8 and USB communication is done using software on AVR mcu. It’s based on the software USB implementation of AVR-CDC. Firmware can be downloaded from the download section of CDC-RS232.

SMD version



3D_PCB_SMD (1)



Throught hole version










    Can this converter be used with laptop? to laod program in pic micro which is inserted in dev.board and dev.board is connected with usb cable to laptop.laptop has a bootloader installed.

    4 years ago
  • Hardik Sharma

    need C program or hex file to load that controller. C program is much better.

    4 years ago
  • Joseph

    Link is not working. Do you have another link?

    4 years ago
  • Aakash

    i’m going to build this converter ….
    but tell me …is it able to program AT89C51/52/53 microcontrollers using TX RX pins
    plz reply soon

    4 years ago
  • Dan

    Sir Ayman, I’m trying to install the driver. I’m using a Atmega328p. My O.S. is a Windows 7 64 bits Ultimate. I follow all the instructions on “Read Me 64 File”. But, doesn’t work yet. The Device is not recognized. And your schematics here in this page, you use a 16 Mhz crystal. But, in CDC 232 page, you use a 12 Mhz Crystal. In the Hex file from CDC 232 page, the 328p Hex file, needs a 12 Mhz and I’m using this. But, there is a Hex File for a 328p with 16 Mhz clock ? since from now, sorry for my terrible self-taught english and thank you Sir in advance for your attention and help.

    3 years ago
  • deepak

    yes, its not working, I cant find the device in my computer.

    3 years ago
  • Matthias Werner

    only works under Windows 7 and lower.
    On Linux on all recent versions.

    Windows 8/10 does not work.

    2 years ago
  • Steven


    Just wondering – for the smd version of your board, there is no ISP header. How do you load the firmware into the ATmega8?


    2 years ago
    • admin

      You will have to temporary hook up wires to the mcu and program the IC or you will have to program it before soldering.

      2 years ago

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