Atmel UC3 Series User manual

Features
•USB DFU boot loaders, version 1.1.0
•Same feature set as version 1.0.3
•These boot loaders do not use any general purpose fuses
•USB protocol
– Based on the USB device firmware upgrade (DFU) class
– Auto-baud (8, 12, and 16MHz crystal on Osc0)
•In-system programming (ISP)
– Configurable I/O start conditions (default is pressing the joystick on Atmel®
EVK1100 and Atmel EVK1101, SW2 button on Atmel EVK1104, PB0 button on
Atmel UC3C-EK, HBUTTON0 button on Atmel UC3-C2-Xplained board) stored in
user page. Protected by 8-bit CRC
– Can be forced by non-volatile configuration bits stored in user page. Protected by
8-bit CRC
– Read/write, on-chip flash memories
– Read device ID
– Full chip erase
– Start application command
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Atmel UC3 32-bit
Microcontroller
AVR UC3 USB
DFU Boot
Loader, Version
1.1.0 and Higher

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1. Description
Atmel AVR®UC3 devices with the USB feature are shipped with a USB boot loader.
This USB boot loader allows in-system programming (ISP) to be performed from a USB host
controller without removing the part from the system, without a preprogrammed application, and
without any external programming interface other than USB.
One boot loader is compiled for each AVR UC3 series. The default hardware I/O conditions
used to request the start of the ISP are also specific to each family.
The USB DFU boot loader, version 1.1.0, has the exact same set of features as the USB DFU
boot loader, versions 1.0.x. The difference is the implementation: Version 1.1.0 does not use
any general purpose fuse for configuration, and uses instead the last two words at the end of the
user page, while version 1.0.3 uses three general purpose fuses (GP29, GP30, and GP31) and
the last word at the end of the user page.
This document describes the USB boot loader functions and its use in various contexts.
2. Related parts
This documentation applies to the following AVR UC3 parts:
•Atmel AT32UC3C0512C, rev. D and higher
•Atmel AT32UC3C0256C, rev. D and higher
•Atmel AT32UC3C0128C, rev. D and higher
•Atmel AT32UC3C064C, rev. D and higher
•Atmel AT32UC3C1512C, rev. D and higher
•Atmel AT32UC3C1256C, rev. D and higher
•Atmel AT32UC3C1128C, rev. D and higher
•Atmel AT32UC3C164C, rev. D and higher
•Atmel AT32UC3C2512C, rev. D and higher
•Atmel AT32UC3C2256C, rev. D and higher
•Atmel AT32UC3C2128C, rev. D and higher
•Atmel AT32UC3C264C, rev. D and higher
Note: The list above is the list of AVR UC3 devices shipped with a preprogrammed USB DFU boot
loader, version 1.1.0 or higher.
Note: The Atmel AT32UC3A0/1, rev. H and higher, the Atmel AT32UC3B0/1, rev. F and higher, and
the Atmel AT32UC3A3, rev. E and higher, can operate with version 1.1.0 of the USB DFU
boot loader, but these devices are shipped preprogrammed with older versions of the boot
loader. For an accurate boot loader version per AVR UC3 devices overview, please refer to
the table of preprogrammed boot loader versions in AVR UC3 devices in Section 8.2.
The boot loader is compiled for each AVR UC3 family because of differences in the MCU periph-
eral memory map. The functionality is the same among families.
3. Related items
• Atmel AVR UC3 A0, A1 Series datasheet:
http://www.atmel.com/dyn/resources/prod_documents/doc32058.pdf
• Atmel AVR UC3 B0, B1 Series datasheet:
http://www.atmel.com/dyn/resources/prod_documents/doc32059.pdf

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• Atmel AVR UC3 A3 Series datasheet:
http://www.atmel.com/dyn/resources/prod_documents/doc32072.pdf
• Atmel AVR UC3 C0, C1, C2 Series datasheet:
http://www.atmel.com/dyn/resources/prod_documents/doc32117.pdf
• Atmel AVR UC3 A0, A1, A3, B0, B1 DFU boot loader up to version 1.0.3:
http://www.atmel.com/dyn/resources/prod_documents/doc7745.pdf
• Atmel AVR Software Framework:
http://www.atmel.com/asf
• Atmel FLIP 3:
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3886
• Atmel AVR32 Studio 2.7:
http://www.atmel.no/beta_ware/

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4. Abbreviations
• ISP: In-system programming
• BOD: Brown-out detector
• USB: Universal serial bus
• DFU: Device firmware upgrade
• avr32program: AVR 32-bit part programmer used with hardware debuggers
• FLIP: Flexible in-system programmer
5. Boot loader environment
The boot loader manages the USB communication protocol and performs read/write operations
from/to the on-chip memories.
The boot loader is located at the beginning of the on-chip flash array, where an area of up to
64KB can be configured to be write protected by the internal flash controller. The boot loader
protected size must be at least the size of the boot loader. On Atmel AT32UC3xxxxx devices, it
is configured to 8KB.
Figure 5-1. Physical environment.
BatchISP is a PC tool that allows a part to be programmed using the Atmel AVR UC3 USB DFU
boot loader. It is compatible with both Windows®and Linux®. It is integrated into Atmel AVR32
Studio by use of a plug-in.
Note that all GCC make files of the Atmel AVR UC3 Software Framework have programming
goals using BatchISP.

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6. Inner workings
6.1 Memory layout
An Atmel AVR UC3 part with the preprogrammed boot loader resets as any other part, at
80000000h. Boot loader execution begins here. The boot loader first performs the boot process
to know whether it should start the USB DFU ISP or the application. If the tested conditions indi-
cate that the USB DFU ISP should be started, then execution continues in the boot loader area
between 80000000h and 80002000h; else the boot loader launches the application at
80002000h.
The conditions tested by the boot process are configured by two 32-bit configuration words
located at the end of the flash user page.
Figure 6-1. The Atmel AT32UC3C0512C non-volatile memory layout with USB DFU boot
loader.
6.2 Configuration
The boot loader configuration is non-volatile and determines the behavior of the boot process
and the ISP. This configuration is stored in the 32 general purpose fuse bits and in the flash user
page (see Figure 6-1).
See the AVR UC3 datasheets for further information about the general purpose fuse bits and the
flash user page.
Application
Bootloader
Reset vector is
@ 80000000h
Application is
@ 80002000h
Flash User Page
Free Flash Space
User page is
@ 80800000h
32-bit bootloader
configuration word1 is
@ 808001FCh &
configuration word2 is
@ 808001F8h
32 GP Fuse
Bits
MCU Address Space
256kB
-Flash
Array
248 kB
8 kB
512 B

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6.2.1 General purpose fuse bits
Atmel AVR UC3 series devices have 32 general purpose fuse bits. When these bits are erased,
they are set to logical 1.
AVR UC3 devices are shipped with their fuses set as follows:
• For Atmel AVR UC3 C series: The general purpose fuses are set to F877FFFFh
•
That is, BOD is enabled, and the boot loader area is set to 8192 bytes.
The general purpose fuse bits can be changed in one of the following ways:
• With a hardware debugger, use the avr32program writefuses command (see avr32program
help writefuses), or execute “Program Fuses...” on the chosen hardware debugger Atmel
AVR32 target in Atmel AVR32 Studio
• With ISP, use the CONFIGURATION memory with BatchISP (see Section 7.4.2), or execute
“Program Fuses...” on the appropriate ISP AVR 32-bit target in AVR32 Studio (see Section
7.5.2)
• From the running embedded application, use the WGPB, EGPB, PGPFB, and EAGPF
FLASHC commands. See the AVR UC3 datasheets for further information, and be careful of
the lock errors that can occur with these commands
6.2.2 Flash user page
6.2.2.1 Description
The boot loader uses two words in the flash user page to store its configuration:
• Configuration Word1 at address 808001FCh is read first at boot time to know if the ISP
process should start unconditionally, and whether it should use Configuration Word2, where
further configuration is stored (see Table 6-1.)
• Configuration Word2 at address 808001F8h stores the I/O conditions that determine
whether the USB DFU ISP or the application is started at the end of the boot process (see
Table 6-2.)

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See Section 6.2.2.2 for the default preprogrammed value of this configuration word.
Table 6-1. Boot loader flash user page Configuration Word1.
Config
Word1 @
808001FCh Name Description
7:0 ISP_CRC8_1 CRC8 of the boot loader Configuration Word1
usingthe polynomial:
P(X) = X8+X2+X+1.
This CRC is used to check the validity of
Configuration Word1.
8 ISP_IO_COND_EN When at 1, tells the boot process to use the user
page Configuration Word2 to determine the I/O
conditions to test to know whetherto start the USB
DFU ISP or the application. Refer to Table 6-2 for a
description of the user page Configuration Word2.
Setting this bit to 0 allows the application to save a
GPIO pin and to free the penultimate word of the
user page, but the ISP will then be unreachable until
the ISP_FORCE bit is set to 1. This behavior can be
useful when extending the Atmel default boot loader
with an applicative boot loader (see Section 7.6.3.3).
9 ISP_FORCE When at 1, tells the boot process to start the USB
DFU ISP process without testing any other
conditions.
15:10 Reserved Reserved. Set to 3Fh.
31:16 ISP_BOOT_KEY_1 Boot key=E11Eh. This key is used to identify this
word as meaningful for the boot loader.

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See Section 6.2.2.2 for the default preprogrammed value of this configuration word.
6.2.2.2 Flash user page configuration words preprogrammed values
The default value of the boot loader flash user page Configuration Word1 is E11EFFD7h (that is,
ISP_FORCE is enabled) for all Atmel AVR UC3 C and D series devices.
The default value of the boot loader flash user page Configuration Word2 is:
• 929E0E62h for the AVR UC3 C0-1 series,
• 929E7504h for the AVR UC3 C2 series,
•
That is, the ISP will be activated when
• the PB0 button onthe UC3C-EK kit is pressed at reset,
• the HBUTTON0 button on the UC3-C2-Xplained kit is pressed at reset,
•
Refer to Section 7.3 for a description of how to customize and program the two configuration
words.
Table 6-2. Boot loader flash user page Configuration Word2.
Config
Word2 @
808001F8h Name Description
7:0 ISP_CRC8_2 CRC8 of the boot loader user page Configuration
Word2 usingthe polynomial:
P(X) = X8+X2+X+1.
This CRC is used to check the validity of
Configuration Word2.
15:8 ISP_IO_COND_PIN The GPIO pin number to test during the boot
process to know whehterto start the USB DFU ISP
or the application. For example, to select PB10 (that
is, QFP144 pin 16 and GPIO pin 42) on the Atmel
AT32UC3A3256, this bit field must be set to 42.
Possible values are:
- 0 to 109 for Atmel AVR UC3 A0 144-pin packages
- 0 to 69 for Atmel AVR UC3 A1 100-pin packages
- 0 to 109 for Atmel AVR UC3 A3 144-pin packages
- 0 to 43 for Atmel AVR UC3 B0 64-pin packages
- 0 to 27 for Atmel AVR UC3 B1 48-pin packages
- 0 to 125 for Atmel AVR UC3 C 144-pin packages
- 0 to 83 for Atmel AVR UC3 C 100-pin packages
- 0 to 47 for Atmel AVR UC3 C 64-pin packages
16 ISP_IO_COND_LEVEL Active level of ISP_IO_COND_PIN that the boot
loader will consider as a request for starting the USB
DFU ISP: 0 for GPIO low level, 1 for GPIO high level
31:17 ISP_BOOT_KEY_2 Boot key = 494Fh. This key is used to identify the
word as meaningful for the boot loader

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6.3 Boot process
After reset, the boot process starts at 80000000h:
• If the ISP_FORCE configuration bit is 1 (see Table 6-1), the USB DFU ISP is immediately
started
• If the ISP_FORCE configuration bit is 0:
– If external events (power-on reset, external reset, OCD reset, JTAG reset, or JTAG
hardware reset) are among the reset causes, the boot process checks if the
ISP_IO_COND_EN configuration bit is 1, and if so, launches either the USB DFU
ISP or the application according to the ISP I/O configuration specified by the user
page Configuration Word2. If ISP_IO_COND_EN is 0, the application is launched.
– If the watchdog timer (WDT) is one of the reset causes, the boot process launches
the application. The watchdog timer is not stopped if the application was running
before reset.
– If an error (BOD or CPU error) is one of the reset causes, the boot process launches
either the USB DFU ISP or the application according to which one was running
before the reset.

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Figure 6-2. Boot process.
Note:
• The ISP_FORCE configuration bit in the user page Configuration Word1 is set to 1 by the
ISP on each ISP command received, and it is set to 0 by the ISP when a request to start the
application is received. That means that after a command has been sent using BatchISP, the
ISP_FORCE=1?
Yes
No
Customer Application
(@ 80002000h)
Note:
ISP_IO_COND_EN and ISP_FORCE are
respectively bit 8 and bit 9 of the user
page configuration word1.
ISP_IO_COND_EN=1?
Reset Vector
(@ 80000000h)
Bootloader
(@ 80000000h)
ISP_FORCE=1 on DFU
Reset Cause:
POR or EXT or OCD or
JTAG or JTAG HW?
Disable WDT
Set ISP RAM Key
ISP RAM Key
Set?
Disable WDT
Clear ISP RAM Key
Yes
No
SW Reset CPU Regs
Reset Cause:
WDT?
No Yes
No
ISP RAM Key
Set?
No
Yes
Yes
ISP User Page Cfg
Word2 OK?
(CRC8, Boot Key, Pin)
No
Yes
ISP I/O Condition Active?
No
Yes
NoYes
ISP_FORCE=0
Start Customer
Application?
Yes
No
Reset
Requested?
NoYes
Jump
WDT Reset
ISP User page
configuration Word1 OK
(CRC8, Boot key)?
Yes
No