Are there available schematics( designs) for Arduino boards and BIOS for them? Is there a tutorial where I can study how Arduino boards work? Thanks
Start here: http://arduino.cc/en/Guide/Introduction
For board schematics and layouts, start here: http://arduino.cc/en/Main/Boards
Thanks for the links.But is there BIOS for Aduino available from which I could be able to learn how Arduino works(in more details) in low level ?
There is no "bios" equivalent. You can look at the reference section
For a list of the main commands available in the language and there is a link to the "libraries" section there as well.
If you want to get really low level get the data sheet for the Atmega328 or Atmega2560 from the Atmel site. This stuff however is lower than most people want or need.
Included in the Arduino IDE download is the "Arduino core" which implements the Arduino-specific library functions. You can read the sources to see how each of the functions is implemented.
Although there isn't a bios, atmega controllers do have so called fuses to set a microcontroller in different modes. The arduino IDE doesn't cover those very much, but you can change 'm using Atmels software and a few other programs. Info on fuses can be found in the controllers datasheet.
Should you want to experiment with 'm, check very carefully what you do, once you set fuses wrong you may not be able to upload new programs and need to reset the chip with a special highvoltage programmer.