User guide

Atmel AVR2054
13
8390B-AVR-12/11
Figure 3-3. OTAU embedded bootloader architecture.
Over-the-Air Upgrade usually requires a special device that will distribute the
application image through the network. To start an upgrade, such device must be
connected to a PC with the Bootloader PC tool installed. The Bootloader PC tool
contains the OTAU tab, which is used to initiate and control an upgrade. For further
details on the topic of OTAU refer to [3].
3.6 Bootloader configuration for RF4CE
The embedded bootloader configuration to support RF4CE applications is primarily
the same as for the common embedded bootloader, but it also provides additional
APIs to support Over-the-Air upgrade and the persistent data storage feature that can
be used by RF4CE applications. The APIs provided by the serial bootloader and the
additional APIs for RF4CE, both make use of self-programming functions. These
extra APIs to support Over-the-Air upgrade and persistent data storage are written
into the RWW section (the bootloader section). These APIs can also be used by other
applications for the purposes as listed below:
• Storing the persistent data (for example, NIB) in the flash memory
• Clearing the persistent data (for example, clear NIB)
• Temporarily storing the updated image in the flash memory
• Replacing the existing application image with the updated image (swapping
functionality)
Please note that bootloader configuration for RF4CE applications do not use any
external flash for the firmware update. Instead, it uses the unutilized internal flash
memory for the Over-the-Air upgrade and persistent data storage.
Please see
rf4ceFlash.h and rf4ceFlash.c files for more details on the API and its
implementation. Additionally, refer to [4]
for more detail regarding RF4CE.
4 Bootloader PC tool
The Bootloader PC tool is a PC application that is used to load a firmware image to a
device programmed with the embedded bootloader code. A device should be
connected to a COM port. Source firmware images shall be in the Motorola S-record
(SREC) format. Such images are created during compilation further to .hex and .elf
images. A device must be programmed with an image of the embedded bootloader
application, which will receive data sent by the Bootloader PC tool and write it to the
device’s flash.