NEX ROBOTICS Fire Bird V ATMEGA2560 Software Manual page 28

NEX Robotics
2.6 Loading your code on robot using AVR Boot loader from NEX Robotics
All AVR microcontrollers can be programmed using In System Programming (ISP), external
programmer or using boot loader. Advantage with the boot loader is that you don't need any
external hardware to load .hex file on the microcontroller. It also protects robot's hardware from
possible damage due to static electricity and prevents any accidental changes in the fuse settings
of the microcontroller.
2.6.1 Boot loader operating principle
If Bootloader firmware is loaded on the microcontroller, it allows in system programming
directly via serial port without any need for the external ISP programmer. Code responsible for
In System Programming via serial port (boot loader) resides in the configurable boot memory
section of the microcontroller. When signaled using external switch while resetting the
microcontroller it gets active and waits for communication from the PC for copying .hex file on
the microcontroller's flash memory. PC sends the .hex file to the microcontroller. Code residing
in the boot section loads the .hex file on the microcontroller's flash memory. After the boot
loading process is complete, newly loaded code can be executed by pressing reset. Once the code
is loaded on the microcontroller UART is free and can be used for other applications. Bootloader
get invoked only if boot switch is kept pressed while microcontroller is reset using reset switch.
Note:
Bootloader code is loaded on the ATMEGA2560 of the Fire Bird V robot using ISP programmer.
It is recommended that you only use Bootloader for the robot. If you use ISP programmer with
the robot then boot section code might get erased and robot will no longer support boot loading.
2.6.2 Programming the robot via Bootloader from NEX Robotics
.hex file can be loaded on the robot via serial port or USB port of the Fire Bird V robot. Robot is
shipped with the bootloader to program robot via USB port.
USB port of the Fire Bird V robot is connected to the UART 2 of the ATMEGA2560
microcontroller via FT232 USB to serial converter. You need to install drivers for FT232 USB to
serial converter on the PC before bootloading.
2.6.3 Installing drivers of FT232 USB to Serial Converter
Steps to install drives for FT232 USB to Serial Converter are covered in detail in the section 6.5
of the Hardware Manual. To identify and change the COM port number, refer to section 6.6 of
the Hardware Manual.
Important:
1. If COM port number is set to more than 8 by the PC then you have to change it in the
range of COM 2 to COM 8 else AVR Bootloader will not program the robot. For
changing COM port number, refer to section 6.6 of the Hardware Manual.
2. When using USB port for the communication, for proper operation first turn on the robot
then insert the USB cable in the robot. We have to follow this sequence because USB to
www.nex-robotics.com
Fire Bird V Software Manual
28