Atmel ATMEGA256RFR2-ZUR User manual

42079A-MCU-02/13
USER GUIDE
Atmel ATMEGA256RFR2 Xplained Pro
Preface
The Atmel® ATMEGA256RFR2 Xplained Pro evaluation kit is hardware platform
to evaluate the ATmega256RFR2 microcontroller.
Supported by the Atmel Studio integrated development platform, the kit provides
easy access to the features of the Atmel ATmega256RFR2 and explains how to
integrate the device in a customer design.
The Xplained Pro MCU series evaluation kits include an on-board Embed-
ded Debugger, and no external tools are necessary to program or debug the
ATmega256RFR2.
The Xplained Pro extension series evaluation kits offers additional peripherals to
extend the features of the board and ease the development of customer designs.

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Table of Contents
Preface .......................................................................................... 1
1. Introduction .............................................................................. 3
1.1. Features .............................................................................. 3
1.2. Kit overview ......................................................................... 3
2. Getting started ......................................................................... 5
2.1. Quick-start ........................................................................... 5
2.2. Connecting the kit ................................................................. 5
2.3. Design documentation and related links ..................................... 5
3. Xplained Pro ............................................................................ 6
3.1. Embedded Debugger ............................................................. 6
3.2. Hardware identification system ................................................. 6
3.3. Power supply ....................................................................... 7
3.3.1. Measuring ATmega256RFR2 power consumption ............ 7
3.4. Standard headers and connectors ............................................ 7
3.4.1. Xplained Pro standard extension header ........................ 7
3.4.2. Power header ........................................................... 8
4. Hardware user guide .............................................................. 9
4.1. Connectors .......................................................................... 9
4.1.1. I/O extension headers ................................................ 9
4.1.2. Other headers ........................................................ 12
4.2. Peripherals ......................................................................... 13
4.2.1. Crystals ................................................................. 13
4.2.2. Mechanical buttons .................................................. 13
4.2.3. LED ...................................................................... 13
4.2.4. RF ........................................................................ 13
4.2.5. Temperature sensor ................................................. 14
4.3. Embedded Debugger implementation ...................................... 14
4.3.1. JTAG ..................................................................... 14
4.3.2. Virtual COM port ..................................................... 15
4.3.3. Atmel Data Gateway Interface ................................... 15
5. Hardware revision history and known issues ........................ 16
5.1. Identifying product ID and revision .......................................... 16
5.2. Revision 3 .......................................................................... 16
6. Document revision history ..................................................... 17
7. Evaluation board/kit important notice .................................... 18
7.1. Evaluation board/kit important notice ....................................... 18

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1. Introduction
1.1 Features
●Atmel® ATmega256RFR2 microcontroller
●Embedded Debugger (EDBG)
●USB interface
●Programming and debugging (target) through JTAG
●Virtual COM-port interface to target via UART
●Atmel Data Gateway Interface (DGI) to target via SPI or TWI
●Four GPIOs connected to target for code instrumentation
●Digital I/O
●Two mechanical buttons (user and reset button)
●One user LED
●Five extension headers
●Antenna
●One ceramic chip antenna (2450BM15A0015E)
●One SMA connector for external antenna
●Temperature sensor and EEPROM (AT30TSE758)
●Two possible power sources
●External power
●Embedded debugger USB
●16MHz crystal
●32kHz crystal
1.2 Kit overview
The Atmel ATMEGA256RFR2 Xplained Pro evaluation kit is a hardware platform to evaluate the Atmel
ATmega256RFR2.
The kit offers a set of features that enables the ATmega256RFR2 user to get started using the
ATmega256RFR2 peripherals right away and to get an understanding of how to integrate the device in their
own design.

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Figure 1.1. ATMEGA256RFR2 Xplained Pro evaluation kit overview.

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2. Getting started
2.1 Quick-start
3 Steps to start exploring the Atmel Xplained Pro Platform
●Download and install Atmel Studio1.
●Launch Atmel Studio.
●Connect an USB cable to the DEBUG USB port.
2.2 Connecting the kit
When connecting Atmel ATMEGA256RFR2 Xplained Pro to your computer for the first time, the operating sys-
tem will do a driver software installation. The driver file supports both 32-bit and 64-bit versions of Microsoft®
Windows® XP and Windows 7.
Once connected the green power LED will be lit and Atmel Studio will autodetect which Xplained Pro evalua-
tion- and extension kit(s) that's connected. You'll be presented with relevant information like datasheets and kit
documentation. You also have the option to launch Atmel Software Framework (ASF) example applications.
The target device is programmed and debugged by the on-board Embedded Debugger and no external pro-
grammer or debugger tool is needed. Please refer to the Atmel Studio user guide2 for information regarding
how to compile and program the kit.
2.3 Design documentation and related links
The following list contains links to the most relevant documents and software for the ATMEGA256RFR2
Xplained Pro.
1. Xplained Pro products 3 - Atmel Xplained Pro is a series of small-sized and easy-to-use evaluation kits
for 8- and 32-bit Atmel microcontrollers. It consists of a series of low cost MCU boards for evaluation and
demonstration of features and capabilities of different MCU families.
2. ATMEGA256RFR2 Xplained Pro User Guide 4 - PDF version of this User Guide.
3. ATMEGA256RFR2 Xplained Pro Design Documentation 5 - Package containing schematics, BOM, as-
sembly drawings, 3D plots, layer plots etc.
4. Atmel Studio 6 - Free Atmel IDE for development of C/C++ and assembler code for Atmel microcontrollers.
5. IAR Embedded Workbench® 7 for Atmel AVR®. This is a commercial C/C++ compiler that is available for
8-bit AVR. There is a 30 day evaluation version as well as a 4k code size limited kick-start version available
from their website.
6. Atmel sample store 8 - Atmel sample store where you can order samples of devices.
1 http://www.atmel.com/atmelstudio
2 http://www.atmel.com/atmelstudio
3 http://www.atmel.com/XplainedPro
4 http://www.atmel.com/Images/Atmel-42079-ATMEGA256RFR2-Xplained-Pro_User-Guide.pdf
5 http://www.atmel.com/Images/Atmel-42079-ATMEGA256RFR2-Xplained-Pro_User-Guide.zip
6 http://www.atmel.com/atmelstudio
7 http://www.iar.com/en/Products/IAR-Embedded-Workbench/AVR/
8 http://www.atmel.com/system/samplesstore

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3. Xplained Pro
Xplained Pro is an evaluation platform that provides the full Atmel microcontroller experience. The platform
consists of a series of Microcontroller (MCU) boards and extension boards that are integrated with Atmel
Studio, have Atmel Software Framework (ASF) drivers and demo code, support data streaming and more.
Xplained Pro MCU boards support a wide range of Xplained Pro extension boards that are connected through
a set of standardized headers and connectors. Each extension board has an identification (ID) chip to unique-
ly identify which boards are mounted on a Xplained Pro MCU board. This information is used to present rele-
vant user guides, application notes, datasheets and example code through Atmel Studio. Available Xplained
Pro MCU and extension boards can be purchased in the Atmel Web Store1.
3.1 Embedded Debugger
The ATMEGA256RFR2 Xplained Pro contains the Atmel® Embedded Debugger (EDBG) for on-board debug-
ging. The EDBG is a composite USB device of 3 interfaces; a debugger, Virtual COM Port and Data Gateway
Interface (DGI).
In conjunction with Atmel Studio, the EDBG debugger interface can program and debug the ATmega256RFR2.
On the ATMEGA256RFR2 Xplained Pro, the JTAG interface is connected between the EDBG and the
ATmega256RFR2.
The Virtual COM Port is connected to a UART port on the ATmega256RFR2 (see section “Embedded Debug-
ger implementation” on page 14 for pinout), and provides an easy way to communicate with the target appli-
cation through a simple terminal software. It offers variable baud rate, parity and stop bit settings. Note that the
settings on the target device UART must match the settings given in the terminal software.
The DGI consists of several physical data interfaces for communication with the host computer. Please, see
section “Embedded Debugger implementation” on page 14 for available interfaces and pinout. Communica-
tion over the interfaces are bidirectional. It can be used to send events and values from the ATmega256RFR2,
or as a generic printf-style data channel. Traffic over the interfaces can be timestamped on the EDBG for more
accurate tracing of events. Note that timestamping imposes an overhead that reduces maximal throughput. The
DGI uses a proprietary protocol, and is thus only compatible with Atmel Studio.
The EDBG controls two LEDs on ATMEGA256RFR2 Xplained Pro, a power LED and a status LED. Table 3.1,
“EDBG LED control” shows how the LEDs are controlled in different operation modes.
Table 3.1. EDBG LED control
Operation mode Power LED Status LED
Normal operation Power LED is lit when power is
applied to the board.
Activity indicator, LED flashes
every time something happens on
the EDBG.
Bootloader mode (idle) The power LED and the status LED blinks simultaneously.
Bootloader mode (firmware up-
grade)
The power LED and the stauts LED blinks in an alternating pattern.
For further documentation on the EDBG, see the EDBG User Guide.
3.2 Hardware identification system
All Xplained Pro compatible extension boards have an Atmel ATSHA204 crypto authentication chip mount-
ed. This chip contains information that identifies the extension with its name and some extra data. When an
Xplained Pro extension board is connected to an Xplained Pro MCU board the information is read and sent to
Atmel Studio. The Atmel Kits extension, installed with Atmel Studio, will give relevant information, code exam-
ples and links to relevant documents. Table 3.2, “Xplained Pro ID chip content” shows the data fields stored in
the ID chip with example content.
Table 3.2. Xplained Pro ID chip content
Data Field Data Type Example Content
Manufacturer ASCII string Atmel’\0’
Product Name ASCII string Segment LCD1 Xplained Pro’\0’
Product Revision ASCII string 02’\0’
Product Serial Number ASCII string 1774020200000010’\0’
1 http://store.atmel.com/

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Data Field Data Type Example Content
Minimum Voltage [mV] uint16_t 3000
Maximum Voltage [mV] uint16_t 3600
Maximum Current [mA] uint16_t 30
3.3 Power supply
The ATMEGA256RFR2 Xplained Pro kit can be powered either by USB or by an external power source through
the 4-pin power header, marked PWR. This connector is described in “Power header” on page 8. The
available power sources and specifications are listed in Table 3.3, “Power sources for ATMEGA256RFR2
Xplained Pro”.
Table 3.3. Power sources for ATMEGA256RFR2 Xplained Pro
Power input Voltage requirements Current requirements Connector marking
External power 4.3 V to 5.5 V Recommended mini-
mum is 500mA to be
able to provide enough
current for extentions
and the board itself.
Recommended maxi-
mum is 2A due to the in-
put protection maximum
current specification.
PWR
Embedded debugger
USB
4.4V to 5.25V (accord-
ing to USB spec)
500 mA (according to
USB spec)
DEBUG USB
The kit will automatically detect which power sources are available and choose which one to use according to
the following priority:
1. External power
2. Embedded debugger USB
3.3.1 Measuring ATmega256RFR2 power consumption
As part of an evaluation of the ATmega256RFR2 it can be of interest to measure its power consumption. Be-
cause the device has a separate power plane (VCC_MCU_P3V3) on this board it is possible to measure the
current consumption by measuring the current that is flowing into this plane. The VCC_MCU_P3V3 plane is
connected via a jumper to the main power plane (VCC_TARGET_P3V3) and by replacing the jumper with an
ampere meter it is possible to determine the current consumption. To locate the current measurement header,
please refer to Figure 1.1, “ATMEGA256RFR2 Xplained Pro evaluation kit overview.”.
Warning Do not power the board without having the jumper or an ampere meter mounted. This can cause
the ATmega256RFR2 to be powered through its I/O pins and cause undefined operation of the
device.
3.4 Standard headers and connectors
3.4.1 Xplained Pro standard extension header
All Xplained Pro kits contains one or more dual row, 20 pin, 100mil extension headers. Xplained Pro MCU
boards have male headers while Xplained Pro extensions have their female counterparts. Note that all pins are
not always connected; However, all the connected pins follow the defined pin-out described in Table 3.4, “Stan-
dard extension header”. The extension headers can be used to connect a wide variety of Xplained Pro exten-
sions to Xplained Pro MCU boards and to access the pins of the target MCU on Xplained Pro MCU board di-
rectly.
Table 3.4. Standard extension header
Pin number Name Description
1 ID Communication line to the ID chip on extension board.

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Pin number Name Description
2 GND Ground
3 ADC(+) Analog to digital converter , alternatively positive part of dif-
ferential ADC
4 ADC(-) Analog to digital converter , alternatively negative part of dif-
ferential ADC
5 GPIO1 General purpose IO
6 GPIO2 General purpose IO
7 PWM(+) Pulse width modulation , alternatively positive part of differ-
ential PWM
8 PWM(-) Pulse width modulation , alternatively positive part of differ-
ential PWM
9 IRQ/GPIO Interrupt request line and/or general purpose IO.
10 SPI_SS_B/GPIO Slave select for SPI and/or general purpose IO.
11 TWI_SDA Data line for two wire interface. Always implemented, bus
type.
12 TWI_SCL Clock line for two wire interface. Always implemented, bus
type.
13 USART_RX Receiver line of Universal Synchronous and Asynchronous
serial Receiver and Transmitter
14 USART_TX Transmitter line of Universal Synchronous and Asynchro-
nous serial Receiver and Transmitter
15 SPI_SS_A Slave select for SPI. Should be unique if possible.
16 SPI_MOSI Master out slave in line of Serial peripheral interface. Always
implemented, bus type
17 SPI_MISO Master in slave out line of Serial peripheral interface. Always
implemented, bus type
18 SPI_SCK Clock for Serial peripheral interface. Always implemented,
bus type
19 GND Ground
20 VCC Power for extension board
3.4.2 Power header
The power header can be used to connect external power to the ATMEGA256RFR2 Xplained Pro kit. The kit
will automatically detect and switch to the external power if supplied. The power header can also be used as
supply for external peripherals or extension boards. Care must be taken not to exceed the total current limita-
tion of the on-board regulator for the 3.3V regulated output. To locate the current measurement header, please
refer to Figure 1.1, “ATMEGA256RFR2 Xplained Pro evaluation kit overview.”
Table 3.5. Power header PWR
Pin number PWR header Pin name Description
1 VEXT_P5V0 External 5V input
2 GND Ground
3 VCC_P5V0 Unregulated 5V (output, derived
from one of the input sources)
4 VCC_P3V3 Regulated 3.3V (output, used as
main power for the kit)
Note If the board is powered from a battery source it is recommended to use the PWR header. If there
is a power source connected to EDBG USB, the EDBG is activated and it will consume more
power.

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4. Hardware user guide
4.1 Connectors
This chapter describes the implementation of the relevant connectors and headers on ATMEGA256RFR2
Xplained Pro and their connection to the ATmega256RFR2. The tables of connections in this chapter also de-
scribes which signals are shared between the headers and on-board functionality.
4.1.1 I/O extension headers
The ATMEGA256RFR2 Xplained Pro headers EXT1, EXT2, EXT3, EXT4 and EXT5 offers access to the I/O
of the microcontroller in order to expand the board e.g. by connecting extension modules to the board. These
headers all comply with the standard extension header specified in Xplained Pro Standard Extension Header.
All headers have a pitch of 2.54 mm.
Table 4.1. Extension header EXT1
Pin on EXT1 ATmega256RFR2 pin Function Shared functionality
1 Communication line to
ID chip on extension
board.
2 GND
3 PF0 ADC0
4 PF1 ADC1
5 PE2 GPIO
6 PE3 GPIO
7 PB5 OC1A EXT4 header.
8 PB6 OC1B
9 PE5 GPIO / INT5 EXT4 header.
10 PD5 GPIO / SPI chip select B EXT4 header.
11 PD1 TWI SDA All EXT headers.
12 PD0 TWI SCL All EXT headers.
13 PE0 UART0 RXD All EXT headers. EXT2,
EXT3 and EXT5 con-
nected through cut-
strap.
14 PE1 UART0 TXD All EXT headers. EXT2,
EXT3 and EXT5 con-
nected through cut-
strap.
15 PG0 GPIO / SPI chip select A EXT4 header.
16 PB2 SPI MOSI All EXT headers.
17 PB3 SPI MISO All EXT headers.
18 PB1 SPI SCK All EXT headers.
19 GND
20 VCC
Table 4.2. Extension header EXT2
Pin on EXT2 ATmega256RFR2 pin Function Shared functionality
1 Communication line to
ID chip on extension
board.
2 GND

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Pin on EXT2 ATmega256RFR2 pin Function Shared functionality
3
4
5
6
7
8
9 PE6 GPIO / INT6 EXT5 header.
10 PD6 GPIO / SPI chip select B EXT5 header.
11 PD1 TWI SDA All other EXT headers.
12 PD0 TWI SCL All other EXT headers.
13 PE01UART0 RXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
14 PE11UART0 TXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
15 PD4 GPIO / SPI chip select A EXT5 header.
16 PB2 SPI MOSI All other EXT headers.
17 PB3 SPI MISO All other EXT headers.
18 PB1 SPI SCK All other EXT headers.
19 GND
20 VCC
Notes: 1Connected through cut-strap
Table 4.3. Extension header EXT3
Pin on EXT3 ATmega256RFR2 pin Function Shared functionality
1 Communication line to
ID chip on extension
board.
2 GND
3 PF3 GPIO
4 PG5 GPIO
5 PB7 GPIO
6
7
8
9 PE7 GPIO / INT7
10 PD7 GPIO / SPI chip select B
11 PD1 TWI SDA All other EXT headers.
12 PD0 TWI SCL All other EXT headers.
13 PE01UART0 RXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
14 PE11UART0 TXD All other EXT headers.
EXT2, EXT3 and EXT5

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Pin on EXT3 ATmega256RFR2 pin Function Shared functionality
connected through cut-
strap.
15 PG4 GPIO / SPI chip select A
16 PB2 SPI MOSI All other EXT headers.
17 PB3 SPI MISO All other EXT headers.
18 PB1 SPI SCK All other EXT headers.
19 GND
20 VCC
Notes: 1Connected through cut-strap
Table 4.4. Extension header EXT4
Pin on EXT4 ATmega256RFR2 pin Function Shared functionality
1 Communication line to
ID chip on extension
board.
2 GND
3
4
5
6
7 PB5 OC1A EXT1 header.
8
9 PE5 GPIO / INT5 EXT1 header.
10 PG0 GPIO / SPI chip select B EXT1 header.
11 PD1 TWI SDA All other EXT headers.
12 PD0 TWI SCL All other EXT headers.
13 PE0 UART0 RXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
14 PE1 UART0 TXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
15 PD5 GPIO / SPI chip select A EXT1 header.
16 PB2 SPI MOSI All other EXT headers.
17 PB3 SPI MISO All other EXT headers.
18 PB1 SPI SCK All other EXT headers.
19 GND
20 VCC
Table 4.5. Extension header EXT5
Pin on EXT5 ATmega256RFR2 pin Function Shared functionality
1 Communication line to
ID chip on extension
board.
2 GND
3

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Pin on EXT5 ATmega256RFR2 pin Function Shared functionality
4
5
6
7
8
9 PE6 GPIO / INT6 EXT2 header.
10 PD4 GPIO / SPI chip select B EXT2 header.
11 PD1 TWI SDA All other EXT headers.
12 PD0 TWI SCL All other EXT headers.
13 PE01UART0 RXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
14 PE11UART0 TXD All other EXT headers.
EXT2, EXT3 and EXT5
connected through cut-
strap.
15 PD6 GPIO / SPI chip select A EXT2 header.
16 PB2 SPI MOSI All other EXT headers.
17 PB3 SPI MISO All other EXT headers.
18 PB1 SPI SCK All other EXT headers.
19 GND
20 VCC
Notes: 1Connected through cut-strap
4.1.2 Other headers
In addition to the “I/O extension headers” on page 9, ATMEGA256RFR2 Xplained Pro has additionally two
headers with spare signals which offers access to the I/O of the microcontroller which are otherwise not easily
available elsewhere or might be favourable to have collected toghether. All headers have a pitch of 2.54mm.
Table 4.6. SPARE ADC signals header
Pin on header ATmega256RFR2
pin
Function Shared functionality
1 - VCC (3.3V)
2 PF4 ADC41JTAG Interface, TCK
3 PF5 ADC51JTAG Interface, TMS
4 PF6 ADC61JTAG Interface, TDO
5 PF7 ADC71JTAG Interface, TDI
Notes: 1These lines are connected to the JTAG interface, and ADC will not work properly while debugging or programming the kit.
Table 4.7. SPARE signals header 2
Pin on header ATmega256RFR2
pin
Function Shared functionality
1 AREF Analog reference
2 TST Test pin for RF test
mode
3 RSTN Reset EDBG and RESET button
4 RSTON Reset status
5 CLKI Alternative main
clock input

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Pin on header ATmega256RFR2
pin
Function Shared functionality
6 GND
4.2 Peripherals
4.2.1 Crystals
The ATMEGA256RFR2 Xplained Pro kit contains two crystals that can be used as clock sources for the
ATmega256RFR2 device. Each crystal has a cut-strap next to it that can be used to measure the oscillator al-
lowance. This is done by cutting the strap and adding a resistor across the strap. More information about oscil-
lator allowance and safety factor can be found in appnote AVR41001
Table 4.8. External 32.768kHz crystals
Pin on ATmega256RFR2 Function
PG3 TOSC2, crystal output
PG4 TOSC1, crystal input
Table 4.9. External 12MHz crystals
Pin on ATmega256RFR2 Function
XTAL1 Crystal input
XTAL2 Crystal output
4.2.2 Mechanical buttons
ATMEGA256RFR2 Xplained Pro contains two mechanical buttons. One button is the RESET button connect-
ed to the ATmega256RFR2 reset line and the other is a generic user configurable button. When a button is
pressed it will drive the I/O line to GND.
Table 4.10. Mechanical buttons
Pin on ATmega256RFR2 Silkscreen text
RSTN RESET
PE4 SW0
4.2.3 LED
There is one yellow LED available on the ATMEGA256RFR2 Xplained Pro board that can be turned on and off.
The LED can be activated by driving the connected I/O line to GND.
Table 4.11. LED connections
Pin on ATmega256RFR2 LED
PB4 Yellow LED
4.2.4 RF
The main feature of ATMEGA256RFR2 Xplained Pro is to show the RF capability of the ATmega256RFR2 de-
vice. This device has bidirectional differential antenna pins, which are fed through a balun (Johanson Technol-
ogy, 2450BM15A00152) to create a single unbalanced output/input. This kit has a passive analog RF switch
(Skyworks Solutions Inc, AS222-92LF3) connected to the unbalanced output of the balun. The switch is dri-
ven by the DIG1 and DIG2 pins of the ATmega256RFR2 which feature Antenna Diversity to enable the device
to automatically select the best signal from two antennas (can also be selected manually). The output of the
switch is connected to a ceramic chip antenna (Johanson Technology, 2540AT18D01004) and a SMA connec-
tor for external antennas.
1 http://www.atmel.com/images/doc8333.pdf
2 http://www.johansontechnology.com/datasheets/balun-filter/2450BM15A0015.pdf
3 http://www.skyworksinc.com/uploads/documents/200252C.pdf
4 http://www.johansontechnology.com/images/stories/ip/rf-antennas/Antenna_2450AT18D0100_v3.pdf

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Table 4.12. RF connections
Pin on ATmega256RFR2
RFP RF balanced output (Positive)
RFN RF balanced output (Negative)
4.2.5 Temperature sensor
ATMEGA256RFR2 Xplained Pro features an Atmel AT30TSE758 temperature sensor chip with an 8kbit serial
EEPROM inside. The sensor includes programmable high and low temperature alarms, user-selectable tem-
perature resolution up to 12 bits, and an I2C/SMBus™ compatible serial interface.
Table 4.13. Temperature sensor connections.
AT30TSE758
temperature
sensor pin
Pin name Pin on
ATmega256RFR2
Comment
1 SDA PD1 Data line of serial interface
2 SCL PD0 Clock line of serial interface
3 ALERT NC1Temperature alarm signalling pin
4 GND GND
5 A2 - Addres line for serial interface, by default pulled low
6 A1 - Addres line for serial interface, by default pulled high
7 A0 - Addres line for serial interface, by default pulled high
8 VCC VCC
Notes: 1Alert pin is available on a testpoint hole close to the sensor.
The temperature sensor has two TWI addresses, one for the temperature sensor and one for the EEPROM.
The addresses are "0b1001 A2 A1 A0" for the temperature sensor and "0b1010 A2 A1 A0" for the EEPROM.
The address selection lines (A2, A1 and A0) of the temperature sensor chip is by default pulled high for A0 and
A1 and low for A2, through 100kΩ resistors, which makes the default addresses 0b1001011 and 0b1010011.
Soldering the the straps on the front of the ATMEGA256RFR2 Xplained Pro board for An will alter that bit in the
address to low or high. Each strap is marked in silkscreen with A0, A1 and A2 as shown in Figure 4.1, “Tem-
perature sensor TWI address.”. When communicating with the EEPROM, part of the TWI address is used as a
page address, for more details see the device datasheet5.
Figure 4.1. Temperature sensor TWI address.
4.3 Embedded Debugger implementation
The ATMEGA256RFR2 Xplained Pro contains an Embedded Debugger (EDBG) that can be used to pro-
gram and debug the ATmega256RFR2 using JTAG. The Embedded Debugger also include a Virtual Com
port interface over UART, an Atmel Data Gateway Interface over SPI and TWI and it monitors four of the
ATmega256RFR2 GPIOs. Atmel Studio can be used as a front end for the Embedded Debugger.
4.3.1 JTAG
The JTAG use five pins to communicate with the target. For further information on how to use the programming
and debugging capabilities of the EDBG, see “Embedded Debugger” on page 6.
5 http://www.atmel.com/Images/doc8751.pdf

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Table 4.14. JTAG connections.
Pin on ATmega256RFR2 Function
PF4 JTAG TCK
PF5 JTAG TMS
PF6 JTAG TDO
PF7 JTAG TDI
RSTN RESET
4.3.2 Virtual COM port
The Embedded Debugger act as a Virtual Com Port gateway by using one of the ATmega256RFR2 UARTs.
For further information on how to use the Virtual COM port see “Embedded Debugger” on page 6.
Table 4.15. Virtual COM port connections.
Pin on ATmega256RFR2 Function
PD2 UART RXD (ATmega256RFR2 RX line)
PD3 UART TXD (ATmega256RFR2 TX line)
4.3.3 Atmel Data Gateway Interface
The Embedded Debugger features an Atmel Data Gateway Interface (DGI) by using either a SPI or TWI port.
The DGI can be used to send a variety of data from the ATmega256RFR2 to the host PC. For further informa-
tion on how to use the DGI interface see “Embedded Debugger” on page 6.
Table 4.16. DGI interface connections when using SPI.
Pin on ATmega256RFR2 Function
PB0 Slave select (ATmega256RFR2 is Master)
PB1 SPI SCK (Clock Out)
PB2 SPI MOSI (Master Out, Slave in)
PB3 SPI MISO (Master In, Slave Out)
Table 4.17. DGI interface connections when using TWI.
Pin on ATmega256RFR2 Function
PD0 SCL (Clock line)
PD1 SDA (Data line)
Four GPIO lines are connected to the Embedded Debugger. The EDBG can monitor these lines and time
stamp pin value changes. This makes it possible to accurately time stamp events in the ATmega256RFR2 ap-
plication code. For further information on how to configure and use the GPIO monitoring features see “Embed-
ded Debugger” on page 6.
Table 4.18. GPIO lines connected to the EDBG.
Pin on ATmega256RFR2 Function
PE2 GPIO0
PE3 GPIO1
PE5 GPIO2
PE6 GPIO3

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5. Hardware revision history and known issues
5.1 Identifying product ID and revision
The revision and product identifier of Xplained Pro boards can be found in two ways, through Atmel Studio or
by looking at the sticker on the bottom side of the PCB.
By connecting a Xplained Pro MCU board to a computer with Atmel Studio running, an information window will
pop up. The first 6 digits of the serial number, which is listed under kit details, contain the product identifier and
revision. Information about connected Xplained Pro extension boards will also appear in the Atmel Kits window.
The same information can be found on the sticker on the bottom side of the PCB. Most kits will print the identifi-
er and revision in plain text as A09-nnnn\rr where nnnn is the identifier and rr is the revision. Boards with limited
space have a sticker with only a QR-code which contains a serial number string.
The serial number string has the following format:
"nnnnrrssssssssss"
n = product identifier
r = revision
s = serial number
The kit identifier for ATMEGA256RFR2 Xplained Pro is 1784.
5.2 Revision 3
Revision 3 of ATMEGA256RFR2 Xplained Pro is the initial released version.

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6. Document revision history
Doc. Rev. Date Comment
A 25.02.2013 First release

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7. Evaluation board/kit important notice
7.1 Evaluation board/kit important notice
This evaluation board/kit is intended for use for FURTHER ENGINEERING, DEVELOPMENT, DEMONS-
TRATION, OR EVALUATION PURPOSES ONLY. It is not a finished product and may not (yet) comply with
some or any technical or legal requirements that are applicable to finished products, including, without limita-
tion, directives regarding electromagnetic compatibility, recycling (WEEE), FCC, CE or UL (except as may be
otherwise noted on the board/kit). Atmel supplied this board/kit "AS IS," without any warranties, with all faults,
at the buyer's and further users' sole risk. The user assumes all responsibility and liability for proper and safe
handling of the goods. Further, the user indemnifies Atmel from all claims arising from the handling or use of
the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appro-
priate precautions with regard to electrostatic discharge and any other technical or legal concerns.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER USER NOR ATMEL SHALL
BE LIABLE TO EACH OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAM-
AGES.
No license is granted under any patent right or other intellectual property right of Atmel covering or relating to
any machine, process, or combination in which such Atmel products or services might be or are used.
Mailing Address: Atmel Corporation, 1600 Technology Drive, San Jose, CA 95110

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© 2013 Atmel Corporation. All rights reserved. / Rev.: 42079A-MCU-02/13
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