ThingMagic M5e-Compact - Manual (Page 27)

SW Overview
Introduction 27
Boot Loader
The boot loader provides low-level functionality. This program provides a customer
interface for upgrading the application firmware and storing data into flash.
When a module is powered up or reset, the boot loader code is automatically copied from
sector 0 of flash into the Microprocessor’s on-chip RAM, and executed. The boot loader
provides the following features:
Ability to read / write / erase flash memory
Upgrade application FW
Change serial baud rate
Verify image CRC
Application Firmware
The application firmware (FW) is an important software component of the module. It
contains the protocol code as well as all the user interfaces to set and get various system
parameters. The application FW is started using the Boot Firmware
command in the
boot loader; it does not start by itself upon power up.
Note
You can use the Reader Assistant to upgrade the reader firmware through
the bootloader.
Verifying Application FW Image CRC
The application FW has an image level Cyclic Redundancy Check (CRC) embedded in it
to protect against corrupted firmware during an upgrade process. (If the upgrade is
unsuccessful, the CRC will not match the contents in flash.) When the boot loader starts
the application FW, it first verifies that the image CRC is correct. If this check fails, then
the boot loader does not start the application FW.
The upgrade process uses a series of individual 250-byte packet write operations to
ensure that an upgrade is successfully completed for the complete image. It also ensures
that the application FW in flash was not corrupted accidently, and can be expected to
perform properly when executed.