N S K E L E C T R O N I C S

A brief word about bootloaders:

Generally, a bootloader is a small program which runs at boot time and is capable of loading a complete application program into a processor's memory so that it can be exectuted. Note that the bootloader runs on the same processor into which it is loading a new program.

In the case of AVR processors, the bootloader program is usually 256-4096 assembly instuctions long and resides in a special portion of the FLASH memory called the bootblock. At boot time (when the processor has just been reset) the bootloader starts and is capable of communicating with the outside world to retrieve a new program and program it into the processor's FLASH memory. Depending on the bootloader and the available hardware, new application code can be loaded from any source including the serial port, SPI or I2C interfaces, external memory, hard disks, flash cards, etc. Once the programming is done, the bootloader program exits or the processor is reset and begins running the newly loaded code. Only AVR processors with the self-programming memory feature (those that have an SPM assembly instruction) can run a bootloader.


STKLOAD: A STK500-Emulating Bootloader

This bootloader is written to emulate Atmel's well-known STK500 AVR development board. The STK500 uses a block transfer protocol to quickly program AVR processors using a standard serial port connection and ordinary RS-232 signaling. With this bootloader installed, you will be able to program your processor from Atmel AVR Studio, just like you would if you were using an STK500 board. For most processors, a complete programming cycle takes 5-10 seconds.

With the bootloader installed, your processor will act like an STK500 board for the first 3 seconds after RESET. If within these three seconds you open an STK500 programming session in AVR Studio, your processor will be automatically detected and you will be able to load new application code. See the manual or on-line help for AVR Studio on how to do this...it's quite trivial. After loading new application code, you can exit the bootloader by pressing RESET.

If no programming instructions are received over the serial port within 3 seconds after RESET, the bootloader will timeout and the currently loaded application will run automatically. NOTE: If there is no currently loaded application (ie. the FLASH memory is blank), then the bootloader will run repeatedly until programming commands are received.

GET THE BOOTLOADER ENABLED READY CHIP IN NSK NOW !

Just 3 Steps to program The chip

• Connect The Chip Thru RS232 to PC Serial Port
• Open The AVR Studio
• Connect Thru STK 500
• Open The Hex File to input Hex File
• Finish Flashing