1. Programming Atmega using BootLoader
Many expensive programmers exist for the Atmega, but after many hours of research, we have put
together this guide to explain how to program the Atmega without the use of a programmer. The
programmer like AVR ISP MKII USB or STK500 is required only once before the Atmega can program
itself. The key to self‐programming is Atmega’s bootloader capability.
Gather resources
Ensure that you have the following resources ready:
1. Atmega 324 (bootloader hex files are provided )
2. Ensure 16Mhz external crystal because bootloader is programmed for this frequency setting
3. STK500 or AVR ISP MKII USB Programmer (one‐time use)
4. Latest version of AVR Studio – Download from Atmel’s website
5. Install MegaLoad.Net program (provided)
6. Make a note of the location of bootLoader_512Byte_Atmega324_9600bps.hex file.
7. Power up your PCB and connect the ISP programming cable to your PCB.
Program the BootLoader
1. Open AVR Studio and choose to connect to your Atmega to program the bootloader
AVR Studio Tools Program AVR Connect
2. Either choose STK500 and COM port or AVR ISP MKII USB depending on your programmer
3. Ensure correct chip type is selected by going to “Program” tab and selecting “Atmega324P”
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2. 4. Go to “Board” Tab and select “125Khz” ISP Frequency and click “Write”
5. Go to “Fuses” tab and choose the following configuration ‐ note the 5 check marks and uncheck
everything else:
6. Choose “Program” to program the fuse bits.
7. Go back to “Board” Tab and select “1Mhz” and click “Write”
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3. 8. Go to the “Program” Tab and click on the “…” button next to “Input HEX File” under FLASH
section and browse to bootLoader_Atmega324_9600bps.hex file and hit Program button:
9. You have successfully loaded the bootloader software.
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4. Program the chip using the self­programming bootloader software
After loading the bootloader program, the actual programming hex file can be loaded easily using the
MegaLoad.Net program.
1. Compile your project in CodeVision or similar compiler.
2. Locate your program’s HEX file in your CodeVision project directory
3. Connect your serial cable to microcontroller’s serial input which is PD0 and PD1. Reference your
PCB manual for details on how to setup serial input and output.
4. Turn on your microcontroller.
5. Open MegaLoad.Net and click on “OPEN” for FLASH file and browse to the hex file from step 2.
6. Click on “Open Port” button until Port opens up.
7. Your Atmega should have programmed automatically after the COM PORT opened up, if not,
then hit the “reset” switch on the PCB.
8. To load new programming file, compile your project in CodeVision and hit Atmega’s reset switch
and MegaLoad.Net will automatically install the new file. If you do not want to program the
chip, simply close MegaLoad.Net to avoid unintentional programming.
Tips for advanced users
1. You could use “bootLoader_Atmega324_38400bps.hex” file when you programmed the boot
loader. This way, MegaLoad.net would program 4 times faster when you open the COM PORT
at 38400bps. The only slight problem is that if you are using Xbee wireless transceivers to
program, you would need to change the Xbee’s transmission rate to 38400bps as well. You can
use XCTU to easily do it. In theory, wireless transmission errors occur more at higher bps so
consider it before you use 38400, although Xbee’s tend to be very reliable.
References
http://www.microsyl.com/
http://www.imagecraft.com/
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