Slovenská verzia je tu

Implementation USB into microcontroller Igor Atmel-USB device
USB-RS232 converter + USB-8/16bit converter + USB-EEPROM scratch pad
based on cheap AVR microcontroller

  Purpose of this article is to inform readers about implementation USB to RS232 converter into singlechip microcontroller, which this interface directly not supports. Simply: implementation USB interface on firmware level (similar as emulation of RS232 interface in microcontrollers, which not have RS232 support). Given project is the next follower of my project of basic USB module IgorPlug-USB (AVR) (computer remote control IgorPlug with USB).

For use in user applications I developed improved USB to RS232 converter (+ another interfaces) with next features:
Device is intended for embedding into your products (source codes of firmware and software is free). For better choice I have prepared two versions, which are different in used processor type. Simpler version is based on AT90S2313 processor. Improved version is based on ATmega8 (see and read bellow its features).

Receiving FIFO buffer :
 - AT90S2313: 32 byte FIFO
 - ATmega8: 800 byte FIFO 

Communication speed and link parameters: 
 - AT90S2313: from 4800 baud to 57600 baud, 8 databits, 1 stopbit
 - ATmega8: from 300 baud up to 115200 baud + possibility to change databits (5,6,7,8), stopbits (1, 2), parity (none, odd, even, mark, space)

Additional build in interfaces and possible extensions
 - AT90S2313: 

 - ATmega8:

Application access: 

Practical experiences: 

And here is example: my testing application "IgorPlugUSBdemo.exe" (receiving of file "msdos.sys" from RS232  terminal TeraTerm.exe):

Testing application - to show the functions of device Igor Atmel-USB

    Next information will be frequently added (last update: 20.10.2004).
Whole project will be in future accessible on webpages of Atmel company as Application Note. On the following picture is Project structure (source codes, firmware, binaries, documentation, ...) :

Project structure (source codes, binaries, documentation, ...)

English Application Note is here and full project is available as Zip archive (cca 3MB) for DOWNLOAD. Now is here all source codes !!!

Internet links: - Hardware section (AVR)_eng.htm
- baseline project of simple USB device  - infrared remote control of computer - company in which I am working and developing something from another brand - all about USB bus
and another: ...

This webpage will be continuously updated - new information (about which you are interested).

author: Ing. Igor Češko: