Atmel AVR1605 User manual

AVR1605: XMEGA™ Boot Loader Quick Start
Guide
Features
• XMEGA boot loader
• AVROSP compatible
• Example application
• C-code sample application for Self Programming
• Read and Write Both Flash and EEPROM Memories
• Read and Write Lock Bits
• Read Fuse Bits
1 Introduction
This application note describes how to use a boot loader application with one of the
XMEGA family devices (i.e. ATxmega128A1) and how an AVR®with the Store
Program Memory (SPM) instruction can be configured for Self-programming. The
sample application communicates via the UART with a PC running the AVR Open
Source Programmer (AVROSP) from Application note AVR911. This enables the
user to download Applications into Flash, Data to EEPROM and to read/write fuses
without the need for an external programmer. The example software is using the
ATxmega128A1 device with STK®600 as a target board.
Electronic designs including a microcontroller always need to be equipped with a
firmware, be it a portable music player, a hairdryer or a sewing machine. As many
Electronic designs evolve rapidly there is a growing need for being able to update
Products, which have already been shipped or sold. It may prove difficult to make
changes to the hardware, especially if the product has already reached the end
customer. But the firmware can easily be updated on products based on Flash
microcontrollers, such as the AVR family.
Many AVR microcontrollers are configured such that it is possible to create a boot
loader able to receive firmware updates and to reprogram the Flash memory on
demand. The program memory space is divided in two sections: the Boot loader
Section (BLS) and the Application Section. A Boot Loader program is placed inside
the Boot Section of the Flash memory. This program handles communication with
the host PC, and facilitates programming of both Flash and EEPROM. Once
programmed, different levels of protection can be individually applied to both the
boot and application portion of the Flash memory. The AVR thus offers a unique
flexibility, allowing the user extensive degrees of memory protection.
For general information about self programming please refer to application note
AVR109: Self programming.
8-bit
Microcontrollers
Application Note
Preliminary
Rev. 8242A-AVR-05/09

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Figure 1-1. Purpose of Bootloader

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2 Getting up and running
This section walks you through the basic steps for getting up and running, by setting
up the hardware. The necessary setup and requirements are described along with
relevant information.
2.1 Hardware Setup
This section gives the step by step procedure to setup the hardware for the
experiment.
The Boot Loader software presented in this application note uses the AVR Open
Source Programmer (AVROSP) as the user interface. The example application
implements functions to read or update the Flash and EEPROM memories on the
target device. It is also possible to read and update the Lock bits and read the Fuse
bits of the device using the ATxmega128A1 AVR device with STK600.
On the STK600, connect the PD2/PD3 pins to the RXD/TXD pins to route the USART
signals to the RS-232 output.
The STK600 has got two RS232 ports marked CAN (Male Type) and RS232 (Female
Type). Connect a serial cable between the PC and the RS232 (Female Type) port of
STK600.
On STK600, connect the PD4 pin to the SW0 pin to use micro switch SW0 to enable
boot loader mode.
Please refer STK600 User Guide, available in AVR Studio®Help to connect it with PC
and to mount the device with correct routing and socket cards combination.
2.2 System Configuration
This section gives the information about setting up your PC prior to start the
implementation.
Include the xml_dev_files directory path (found in code\AVROSP_Test) to the
windows PATH by creating a variable name and value. This is set because the
system will search the default locations for the AVROSP.exe file to run from any
location of the directory. If this is not done, then you can use AVROSP.exe in the
folder where it is and you can not call it anywhere else. It can be set by right clicking
My Computer icon and selecting the Properties option as demonstrated in the Figure
2.2-1, 2, 3 below. (You may need to restart the computer to enable the changes).

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Figure 2.2-1. PATH Configuration 1
Figure 2.2-2. PATH Configuration 2

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Figure 2.2-3. PATH Configuration 3
2.3 Starting a debug session
This section gives the step by step procedure to start the debugging session on the
device.
Start IARTM (v5.12C or later) and select the option “Open existing workspace”. Browse
for the folder downloaded along with this Application note (hereafter called as target
folder) and select bootloader.eww for debugging. Verify that there are no errors or
warnings by build and compilation.
Start AVR Studio and create a new project using bootldr.dbg. Select the device as
ATxmega128A1 and the platform as JTAGICE mkII.
Make sure that both the STK600 and JTAGICE mkII is Powered ON.
In AVR studio open the programming dialog and connect to the ATxmega128A1
using the JTAG or the PDI interface. Select the fuses tab and set the BOOTRST fuse
to Boot loader Reset and program the fuses.
Start a debugger session in AVR Studio and run the application while keeping SW0
pressed on the STK600 (Check the LED status of the Tool).
In Programming mode, the program receives commands from AVROSP via the
UART. Each command executes an associated task. Any command not recognized
by the boot loader program results in a “?” being sent back to AVROSP.
Through explorer, open the folder AVROSP_Test where several command line
examples, example hex files for FLASH and EEPROM, the AVROSP.exe and the
XML part description file for the ATxmega128A1 are available.
NOTE: Default PC’s RS232 port is set to COM1, if the STK600 is connected to
another port the following batch programs need to be modified. The batch files are as
follows:
x128A1_chip_erase.bat
x128A1_eeprom_dump.bat
x128A1_eeprom_write_file.bat
x128A1_flash_dump.bat
x128A1_flash_write_file.bat
In all the batch files the port name COM1 in the first line have to be modified/replaced
with COMx. Where x is the RS232 port number where the STK600 is connected.
The first line of the batch file is shown below which can be viewed by drag-drop of
batch file into notepad application:

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The following command will set up the COM1 in Windows when given in MSDOS
command line:
mode com1 Data=8 Parity=n Baud=9600 DTR=OFF RTS=OFF to=off
3 Communication with the bootloader
This section walks you through the basic steps for communicating with the bootloader
through the hardware setup. The necessary setup and requirements are described
along with relevant information.
3.1 Chip Erase
This section explains how to implement the ‘Chip Erase’ command.
Ensure that the steps to make the device wait in bootloader section are done [Press
both External RESET and SW0 on STK600 and release the RESET first and then the
SW0].
In the current working folder, double-click (run) the batch program called
x128A1_chip_erase.bat
The batch file runs the following command to erase the flash and the EEPROM when
using AVROSP:
AVROSP -dATxmega128A1 -e
Figure 3.1-1 Chip Erase
The command window shown in Figure 3.1-1. Chip Erase should appear: After
connecting to COM1, the device specific file is parsed for the ATxmega128A1 by
AVROSP and the output file is placed in the AVROSP_Test directory. Further, the
signature is matched and a chip erase is performed by the following operations:
1) Given COM port number is scanned

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2) Communicates with AVRBOOT
3) Enters programming mode
4) XML file is parsed and new XML file is generated in the current working folder
5) Signature is checked to match
6) Chip erase is performed
7) Leaves the programming mode
3.2 Write a file to flash
This section explains how to write/download a file to the flash.
Ensure that the steps to make the device wait in bootloader section are done [Press
both External RESET and SW0 buttons on STK600 and release the RESET first and
then the SW0].
In windows explorer, run the batch file x128A1_flash_write_file.bat. The batch file
runs the following command to program and verify the flash memory:
AVROSP -dATxmega128A1 -e -ifflash.hex -pf -vf
Table 3.2 -1. Command Description
Command Description
-e This command will erase the flash the device.
-ifflash.hex This command will give the ‘flash.hex’ file as an input file for programming the
flash
-pf This command will program the flash
-vf This command will verify the flash content after programming
After comparing, by the verification command, “Equal!” string in the command window
is to be noted which ensures that the programming of flash memory with the given
input file is performed without any error.
Refer Figure 3.2-1 Downloading to Flash where you can see the “Equal!” string.

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Figure 3.2-1. Downloading to Flash
3.3 Run the uploaded application from address 0
The flash.hex is a program that writes the string “Congratulations!” when it gets the
character ‘E’ through serial/RS232 port.
The program will jump to the application section after RESET, provided the micro
switch SW0 in not pressed at the time of RESET. Alternatively, the application can be
run by setting the BOOTRST fuse to Application Boot and restart the part. (Note that
a start of another debugging session will perform a chip erase).
Now the application will wait for the letter ‘E’ through USART0. To verify the
application that was downloaded to the flash in the previous chapter, we must write
the character ‘E’ through terminal software (e.g. HyperTerminal) as described below:
Open HyperTerminal program available in all the Windows based system by following
the path StartÆAll ProgramsÆAccessoriesÆCommunicationsÆHyper Terminal
Give any name(eg:Test) for that session and configure the COM port settings to 9600
baud, 8bit Data, no parity, 1 stop bit and no Handshaking. Please refer Figure 3.3-
1.Hyperterminal Name and Figure 3.3-2.COM port Settings for more information.
Figure 3.3-1 HyperTerminal Name

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Figure 3.3-2 COM port Settings
Enter the character ‘E’ in the transmission blank space.
In return you will receive a string “Congratulations!” from the device ensuring the
proper operation of the application loaded in the device through boot loader.
3.4 Write a file to EEPROM
Ensure that the steps to make the device wait in bootloader section are done [Press
both External RESET and SW0 buttons on STK600 and release the RESET first and
then the SW0].
In the AVROSP_Test directory, run the batch file x128A1_eeprom_write_file.bat. The
file eeprom.hex containing the ASCII string “This is a test string to the XMEGA
eeprom!” is written to EEPROM by using this AVROSP command:
AVROSP -dATxmega128A1 -e -ieeeprom.hex -pe –ve

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Figure 3.4-1 writing a file to EEPROM
In AVR Studio start a debug session, select memory view from the View menu. Select
EEPROM and verify that the string is located at address 0x00 as in Figure 3.4-2
EEPROM visual verification to verify that the string from eeprom.hex was written
correctly.
Figure 3.4-2 EEPROM visual verification
3.5 File dump from memory
3.5.1 EEPROM
Ensure that the steps to make the device wait in bootloader section are done [Press
both External RESET and SW0 buttons on STK600 and release the RESET first and
then the SW0].
Run the batch file x128A1_eeprom_dump.bat which has the AVROSP command
given below to dump the contents of the EEPROM to the file edump.hex
AVROSP -dATxmega128A1 -re -oeedump.hex
3.5.2 FLASH
Ensure that the steps to make the device wait in bootloader section are done [Press
both External RESET and SW0 buttons on STK600 and release the RESET first and
then the SW0].
Run the batch file x128A1_flash_dump.bat which has the AVROSP command given
below to dump the contents of the FLASH to the file fdump.hex
AVROSP -dATxmega128A1 -rf -offdump.hex