USER GUIDE
Atmel SAM R21 Xplained Pro
Preface
The Atmel® SAM R21 Xplained Pro evaluation kit is a hardware platform to
evaluate the ATSAMR21G18A microcontroller.
Supported by the Atmel Studio integrated development platform, the kit provides
easy access to the features of the Atmel ATSAMR21G18A and explains how to
integrate the device in a custom design.
The Xplained Pro MCU series evaluation kits include an on-board Embedded
Debugger, and no external tools are necessary to program or debug the
ATSAMR21G18A.
The Xplained Pro extension kits offers additional peripherals to extend the
features of the board and ease the development of custom 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 SAM R21 Power Consumption ... ........... .... .... 7
3.4. Standard Headers and Connectors ... .... .... ........... .... .... ........... .. 7
3.4.1. Xplained Pro Standard Extension Header ... .... .... ....... .... 7
3.4.2. Xplained Pro Power Header ........ .... .... ....... .... .... ......... 8
4. Hardware User Guide ........................................................... 10
4.1. Connectors ....... .... .... ........... .... .... ........... .... .... ....... .... .... ..... 10
4.1.1. I/O Extension Headers ...... .... .... ........... .... .... ....... .... . 10
4.1.2. Other Headers and Connectors .. .... ........... .... .... ....... .. 11
4.2. Peripherals ....... .... .... ........... .... .... ........... .... .... ....... .... .... ..... 11
4.2.1. Crystal .... ........... .... .... ........... .... .... ....... .... .... .......... 11
4.2.2. Mechanical Buttons ... .... ....... .... .... ........... .... .... ......... 12
4.2.3. LED .... .... .... ........... .... .... ....... .... .... ........... .... .... ..... 12
4.2.4. USB .... .... .... ........... .... .... ....... .... .... ........... .... .... ..... 12
4.2.5. RF ........ .... .... ........... .... .... ....... .... .... ........... .... .... ... 12
4.3. 1.8V Operation . ........... .... .... ........... .... .... ....... .... .... ........... ... 13
4.4. Embedded Debugger Implementation ...... .... .... ........... .... .... ..... 14
4.4.1. Serial Wire Debug .... .... .... ....... .... .... ........... .... .... ..... 15
4.4.2. Virtual COM port .... ........... .... .... ........... .... .... ....... .... 15
4.4.3. Atmel Data Gateway Interface .......... .... .... ........... .... .. 15
5. Kit Specific Data ................................................................... 16
6. Agency Certification .............................................................. 17
6.1. United States (FCC) ........ .... .... ........... .... .... ....... .... .... ........... 17
6.2. European Union (ETSI) ....... .... .... ........... .... .... ....... .... .... ....... 17
6.3. Canada (IC) ..... .... .... ........... .... .... ....... .... .... ........... .... .... ..... 18
6.4. List of Antennas Tested With This Product . .... .... ....... .... .... ........ 18
7. Hardware Revision History and Known Issues ..................... 19
7.1. Identifying Product ID and Revision .. ........... .... .... ........... .... .... . 19
7.2. Revision 3 .. ........... .... .... ........... .... .... ....... .... .... ........... .... .... 19
8. Document revision history ..................................................... 20
9. Evaluation Board/Kit Important Notice .................................. 21
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1. Introduction
1.1 Features
● Atmel ATSAMR21G18A microcontroller
● Embedded debugger (EDBG)
● USB interface
● Programming and debugging on board SAM R21 through Serial Wire Debug (SWD)
● Virtual COM-port interface to target via UART
● Atmel Data Gateway Interface (DGI) to target via SPI and TWI
● Four GPIOs connected to target for code instrumentation
● Digital I/O
● Two mechanical buttons (user and reset button)
● One user LED
● Two extension headers
● Antenna
● One ceramic chip antenna (2450AT18D0100)
● One SMA connector for external antenna
● Three possible power sources
● External power
● Embedded debugger USB
● Target USB
● 32kHz crystal
● 16MHz crystal
● USB interface, device
1.2 Kit Overview
The Atmel SAM R21 Xplained Pro evaluation kit is a hardware platform to evaluate the Atmel
ATSAMR21G18A.
The kit offers a set of features that enables the ATSAMR21G18A user to get started using the
ATSAMR21G18A 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. SAM R21 Xplained Pro Evaluation Kit Overview
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2. Getting Started
2.1 Quick-start
Three steps to start exploring the Atmel Xplained Pro Platform
● Download and install Atmel Studio
● Launch Atmel Studio
● Connect a Micro-B cable to the DEBUG USB port
2.2 Connecting the Kit
When connecting Atmel SAM R21 Xplained Pro to your computer for the first time, the operating system 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
evaluation- 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 programmer or debugger tool is needed. Refer to the Atmel Studio user guide2 for information
regarding how to compile and program the kit.
1
®
2.3 Design Documentation and Related Links
The following list contains links to the most relevant documents and software for SAM R21 Xplained Pro.
1. Xplained Pro products 3 - Atmel Xplained Pro is a series of small-sized and easy-to-use evaluation kits
for Atmel AVR 8- and 32-bit microcontrollers. It consists of a series of low cost MCU boards for evaluation
and demonstration of features and capabilities of different MCU families.
2. SAM R21 Xplained Pro User Guide 4 - PDF version of this User Guide.
3. SAM R21 Xplained Pro Design Documentation 5 - Package containing schematics, BOM, assembly
drawings, 3D plots, layer plots etc.
4. EDBG User Guide 6 - User guide containing more information about the onboard Embedded Debugger.
5. Atmel Studio 7 - Free Atmel IDE for development of C/C++ and assembler code for Atmel
microcontrollers.
6.
IAR Embedded Workbench® 8 for ARM®. This is a commercial C/C++ compiler that is available for ARM.
There is a 30 day evaluation version as well as a code size limited kick-start version available from their
website. The code size limit is 16KB for devices with M0, M0+ and M1 cores and 32KB for devices with
other cores.
7. Atmel sample store 9 - 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-42243-SAMR21-Xplained-Pro_User-Guide.pdf
5
http://www.atmel.com/Images/Atmel-42243-SAMR21-Xplained-Pro_User-Guide.zip
6
http://www.atmel.com/Images/Atmel-42096-Microcontrollers-Embedded-Debugger_User-Guide.pdf
7
http://www.atmel.com/atmelstudio
8
http://www.iar.com/en/Products/IAR-Embedded-Workbench/ARM/
9
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 uniquely
identify which boards are mounted on a Xplained Pro MCU board. This information is used to present relevant
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 SAM R21 Xplained Pro contains the Atmel Embedded Debugger (EDBG) for on-board debugging. The
EDBG is a composite USB device of three 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 ATSAMR21G18A.
On the SAM R21 Xplained Pro, the SWD interface is connected between the EDBG and the ATSAMR21G18A.
The Virtual COM Port is connected to a UART port on the ATSAMR21G18A (see section “Embedded Debugger
Implementation” on page 14 for pinout), and provides an easy way to communicate with the target
application through 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. See section
“Embedded Debugger Implementation” on page 14 for available interfaces and pinout. Communication
over the interfaces are bidirectional. It can be used to send events and values from the ATSAMR21G18A, 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 SAM R21 Xplained Pro, a power LED and a status LED. Table 3-1, “EDBG
LED Control” on page 6 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.
Bootloader mode (idle) The power LED and the status LED blinks simultaneously.
Bootloader mode (firmware
The power LED and the status LED blinks in an alternating pattern.
upgrade)
For further documentation on the EDBG, see the EDBG User Guide2.
3.2 Hardware Identification System
All Xplained Pro compatible extension boards have an Atmel ATSHA204 CryptoAuthentication™ chip mounted.
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
examples and links to relevant documents. Table 3-2, “Xplained Pro ID Chip Content” on page 6 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’
Activity indicator, LED flashes
every time something happens on
the EDBG.
1
http://store.atmel.com/ATSAMR21-XPRO
2
http://www.atmel.com/Images/Atmel-42096-Microcontrollers-Embedded-Debugger_User-Guide.pdf
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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 SAM R21 Xplained Pro kit can be powered either by USB or by an external power source through the 4pin power header, marked PWR. This connector is described in “Xplained Pro Power Header” on page 8.
The available power sources and specifications are listed in Table 3-3, “Power Sources for SAM R21 Xplained
Pro” on page 7.
Table 3-3. Power Sources for SAM R21 Xplained Pro
Power input Voltage requirements Current requirements Connector marking
External power 5V ± 2 % (± 100mV) for
USB host operation.
4.3V to 5.5V if USB host
operation is not required
Embedded debugger
USB
4.4V to 5.25V
(according to USB spec)
Target USB 4.4V to 5.25V
(according to USB spec)
Recommended
minimum is 1A to
be able to provide
enough current for
connected USB
devices and the board
itself. Recommended
maximum is 2A due
to the input protection
maximum current
specification.
500mA (according to
USB spec)
500mA (according to
USB spec)
PWR
EDBG USB
TARGET 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. Target USB.
Note
External power is required when the 500mA through the USB connector is not enough to power a
connected USB device in a USB host application.
3.3.1 Measuring SAM R21 Power Consumption
As part of an evaluation of the SAM R21 it can be of interest to measure its power consumption. Because 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 ammeter it is
possible to determine the current consumption. To locate the current measurement header, refer to Figure 1-1,
“SAM R21 Xplained Pro Evaluation Kit Overview” on page 4.
Warning
Do not power the board without having the jumper or an ammeter mounted. This can cause the
SAM R21 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 have 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
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always connected. However, all the connected pins follow the defined pin-out described in Table 3-4, “Xplained
Pro Extension Header” on page 8. The extension headers can be used to connect a wide variety of
Xplained Pro extensions to Xplained Pro MCU boards and to access the pins of the target MCU on Xplained
Pro MCU board directly.
Table 3-4. Xplained Pro Extension Header
Pin number Name Description
1 ID Communication line to the ID chip on extension board.
2 GND Ground.
3 ADC(+) Analog to digital converter , alternatively positive part of
differential ADC.
4 ADC(-) Analog to digital converter , alternatively negative part of
differential ADC.
5 GPIO1 General purpose I/O.
6 GPIO2 General purpose I/O.
7 PWM(+) Pulse width modulation , alternatively positive part of
differential PWM.
8 PWM(-) Pulse width modulation , alternatively positive part of
differential PWM.
9 IRQ/GPIO Interrupt request line and/or general purpose I/O.
10 SPI_SS_B/GPIO Slave select for SPI and/or general purpose I/O.
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
Asynchronous 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 Xplained Pro Power Header
The power header can be used to connect external power to the SAM R21 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 limitation
of the on-board regulator for the 3.3V regulated output. To locate the current measurement header, refer to
Figure 1-1, “SAM R21 Xplained Pro Evaluation Kit Overview” on page 4
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)
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Pin number PWR header Pin name Description
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 SAM R21 Xplained Pro
and their connection to the ATSAMR21G18A. The tables of connections in this chapter also describes which
signals are shared between the headers and on-board functionality.
4.1.1 I/O Extension Headers
The SAM R21 Xplained Pro headers EXT1 and EXT3 offer access to the I/O of the microcontroller in order
to expand the board e.g. by connecting extensions to the board. These headers all comply with the standard
extension header specified in Xplained Pro Standard Extension Header on page 7. All headers have a pitch of
2.54mm.
Table 4-1. Extension Header EXT1
Pin on EXT1 SAM R21 pin Function Shared functionality
1 [ID] - Communication line to ID chip
on extension board
2 [GND] - GND
3 [ADC(+)] PA06 AIN[6]
4 [ADC(-)] PA07 AIN[7]
5 [GPIO1] PA13 GPIO
6 [GPIO2] PA28 GPIO
7 [PWM(+)] PA18 TCC0 / WO[2]
8 [PWM(-)] PA19 TCC0 / WO[3]
9 [IRQ/GPIO] PA22 EXTINT[6]
10 [SPI_SS_B/GPIO] PA23 GPIO
11 [TWI_SDA] PA16 SERCOM1 PAD[0] I²C SDA EXT3 and EDBG
12 [TWI_SCL] PA17 SERCOM1 PAD[1] I²C SCL EXT3 and EDBG
13 [USART_RX] PA05 SERCOM0 PAD[1] UART RX EDBG
14 [USART_TX] PA04 SERCOM0 PAD[0] UART TX EDBG
15 [SPI_SS_A] PB03 SERCOM5 PAD[1] SPI SS
16 [SPI_MOSI] PB22 SERCOM5 PAD[2] SPI MOSI EXT3 and EDBG
17 [SPI_MISO] PB02 SERCOM5 PAD[0] SPI MISO EXT3 and EDBG
18 [SPI_SCK] PB23 SERCOM5 PAD[3] SPI SCK EXT3 and EDBG
19 [GND] - GND
20 [VCC] - VCC
Table 4-2. Extension Header EXT3
Pin on EXT3 SAM R21 pin Function Shared functionality
1 [ID] - Communication line to ID chip
on extension board
2 [GND] - GND
3 [ADC(+)] - -
4 [ADC(-)] - -
5 [GPIO1] PA15 GPIO
6 [GPIO2] -
7 [PWM(+)] -
8 [PWM(-)] -
9 [IRQ/GPIO] -
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Pin on EXT3 SAM R21 pin Function Shared functionality
10 [SPI_SS_B/GPIO] PA08 GPIO EDBG
11 [TWI_SDA] PA16 SERCOM1 PAD[0] I²C SDA EXT1 and EDBG
12 [TWI_SCL] PA17 SERCOM1 PAD[1] I²C SCL EXT1 and EDBG
13 [USART_RX] - -
14 [USART_TX] - -
15 [SPI_SS_A] PA14 GPIO EDBG
16 [SPI_MOSI] PB22 SERCOM5 PAD[2] SPI MOSI EXT1 and EDBG
17 [SPI_MISO] PB02 SERCOM5 PAD[0] SPI MISO EXT1 and EDBG
18 [SPI_SCK] PB23 SERCOM5 PAD[3] SPI SCK EXT1 and EDBG
19 [GND] - GND
20 [VCC] - VCC
4.1.2 Other Headers and Connectors
There are two headers that are not mounted on the kit from production. These headers contains signals that
are otherwise not easily accecible on the kit.
4.1.2.1 Altnernate Signals Header
The alternate signals header is marked with "Alternate" in silkscreen of the kit, the signals provided here are
otherwise hard to do measurements on.
Table 4-3. Alternate Signals Header
Pin on header Pin on SAM R21 Function
1 PA09 RFCTRL1, negative antenna switch control signal
2 PA12 RFCTRL2, positive antenna switch control signal
3 PA27 GPIO, chip select on the EDBG DGI SPI bus
4.1.2.2 Cortex Debug Connector
The Cortex debug connector is provided to enable external debuggers to be connected to the
ATSAMR21G18A. The footpring is made for a 2x5 50mil connector and the pinout is shown in Table 4-4,
“Cortex Debug Connector” on page 11. This header should only be used when the EDBG is disconnected
from the target, for more information see “1.8V Operation” on page 13.
Table 4-4. Cortex Debug Connector
Pin on connector Connected Function
1 VCC Target Voltage reference
2 PA31_SWDIO Debug data
3 GND GND
4 PA30_SWCLK Debug clock
5 GND GND
6 NC -
7 NC -
8 NC -
9 GND GND detect
10 RESETN Target reset
4.2 Peripherals
4.2.1 Crystal
The SAM R21 Xplained Pro kit contains one crystals that can be used as clock source for the SAM R21 device.
The crystal has a cut-strap next to it that can be used to measure the oscillator safety factor. This is done by
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cutting the strap and adding a resistor across the strap. More information about oscillator allowance and safety
factor can be found in appnote AVR41001.
Note
The 16MHz crystal is connected directly to the RF die inside the SAM R21. The clock signal
generated by the crystal is routed from the CLKM pin on the RF die to a GCLK IO pin on the
microcontroller. For more information on how the RF die is connected to the microcontroller and
how to configure the CLKM pin see the SAM R21 datasheet.
Table 4-5. External 32.768kHz Crystal
Pin on SAM R21 Function
PA00 XIN32
PA01 XOUT32
Table 4-6. External 16MHz Crystal
Pin on SAM R21 Function
XTAL1 XIN
XTAL2 XOUT
4.2.2 Mechanical Buttons
SAM R21 Xplained Pro contains two mechanical buttons. One button is the RESET button connected to the
SAM R21 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 4-7. Mechanical Buttons
Pin on SAM R21 Silkscreen text
RESETN RESET
PA28 SW0
4.2.3 LED
There is one yellow LED available on the SAM R21 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 4-8. LED Connections
Pin on SAM R21 LED
PA19 Yellow LED0
4.2.4 USB
The SAM R21 Xplained Pro has a Micro-USB receptable for use with the SAM R21 USB module. To be able to
detect when a USB cable is connected, a GPIO / ADC is used to detect the VBUS voltage on the connector.
Table 4-9. USB Connections
Pin on SAM R21 USB
PA07 VBUS Detection
PA24 USB D-
PA25 USB D+
4.2.5 RF
The main feature of SAM R21 Xplained Pro is to show the RF capability of the ATSAMR21G18A device.
This device has bidirectional 100ohm differential antenna pins, which are fed through a balun (Johanson
1
http://www.atmel.com/images/doc8333.pdf
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Technology, 2450BM15A00152) to create a single 50ohm 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 driven by the RFCTRL1 and RFCTRL2 pins of the ATSAMR21G18A 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 connector for external antennas.
Table 4-10. RF Connections
Pin on SAM R21 RF Shared functionality
RFP RF balanced output (positive)
RFN RF balanced output (negative)
PA09 / RFCTRL1 RF switch control signal
EDBG
(negative)
PA12 / RFCTRL2 RF switch control signal (positive) EDBG
4.3 1.8V Operation
The SAM R21 Xplained Pro board is operated at 3.3V by default, but it also has the possibility of running
at lower voltages from an external supply. The EDBG is designed to run from a 3.3V supply and won't
work on other voltages, therefore all connections from the EDBG and the on board 3.3V regulator to the
ATSAMR21G18A have to be removed. Figure 4-1, “1.8V Operation Modifications” on page 14 shows all
components that have to be removed for 1.8V operation.
When the components are removed the kit can be supplied with a desired voltage through the pins marked 3V3
(pin four) and GND (pin two) on the power header described in “Xplained Pro Power Header” on page 8.
To program and debug the ATSAMR21G18A a 2x5 50mil header has to be mounted above EXT1 as shown in
Figure 1-1, “SAM R21 Xplained Pro Evaluation Kit Overview” on page 4.
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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Note
Important
Operating the SAM R21 Xplained Pro on other voltages than 3.3V requires physical modifications
on the kit using a soldering iron and an external debugger for programming the ATSAMR21G18A.
The on board LED is selected for 3.3V operation, the light level at 1.8V opeartion is very low. To
increase the emitted light level the value of the series resistor can be lowered.
The EDBG functionality can be restored by re-soldering the removed components, they are all 0
ohm resistors.
The voltage supplied through the power header is applied directly to the ATSAMR21G18A and
the extension headers, applying a voltage greater than 3.3V may damage the board permanently.
Figure 4-1. 1.8V Operation Modifications
4.4 Embedded Debugger Implementation
SAM R21 Xplained Pro contains an Embedded Debugger (EDBG) that can be used to program and debug the
ATSAMR21G18A using Serial Wire Debug (SWD). 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 SAM R21
GPIOs. Atmel Studio can be used as a front end for the Embedded Debugger.
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4.4.1 Serial Wire Debug
The Serial Wire Debug (SWD) use two 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.
Table 4-11. SWD Connections
Pin on SAM R21 Function
PA30 SWD clock
PA31 SWD data
4.4.2 Virtual COM port
The Embedded Debugger acts as a Virtual Com Port gateway by using one of the ATSAMR21G18A UARTs.
For further information on how to use the Virtual COM port see “Embedded Debugger” on page 6.
Table 4-12. Virtual COM Port Connections
Pin on SAM R21 Function
PA04 SERCOM0 PAD[0] UART TXD (SAM R21 TX line)
PA05 SERCOM1 PAD[1] UART RXD (SAM R21 RX line)
4.4.3 Atmel Data Gateway Interface
The Embedded Debugger features an Atmel Data Gateway Interface (DGI) by using either a SPI or I²C port.
The DGI can be used to send a variety of data from the SAM R21 to the host PC. For further information on
how to use the DGI interface see “Embedded Debugger” on page 6.
Table 4-13. DGI Interface Connections When Using SPI
Pin on SAM R21 Function
PA27 GPIO SPI SS (Slave select) (SAM R21 is Master)
PB02 SERCOM5 PAD[0] SPI MISO (Master In, Slave Out)
PB22 SERCOM5 PAD[2] SPI MOSI (Master Out, Slave in)
PB23 SERCOM5 PAD[3] SPI SCK (Clock Out)
Table 4-14. DGI Interface Connections When Using I²C
Pin on SAM R21 Function
PA16 SERCOM1 PAD[0] I²C SDA (Data line)
PA17 SERCOM1 PAD[1] I²C SCL (Clock 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 SAM R21 application
code. For further information on how to configure and use the GPIO monitoring features see “Embedded
Debugger” on page 6.
Table 4-15. GPIO Lines Connected to the EDBG
Pin on SAM R21 Function
PA08 GPIO0
PA09 GPIO1
PA12 GPIO2
PA14 GPIO3
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5. Kit Specific Data
One of the user pages in the EDBG is programmed with data specific to the SAM R21 Xplained Pro. The data
can be read through the I2C interface connected to the EDBG, for detailed information see the EDBG User
Guide1. All data is stored as little endian.
Table 5-1. MAC64Register, Offset: 0x00
Name Description Size [bits]
MAC64 MAC64 Address (hex) 64
1
http://www.atmel.com/Images/Atmel-42096-Microcontrollers-Embedded-Debugger_User-Guide.pdf
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6. Agency Certification
6.1 United States (FCC)
This equipment complies with Part 15 of the FCC rules and regulations. To fulfill FCC Certification
requirements, an OEM manufacturer must comply with the following regulations:
1. This equipment (SAM R21 Xplained Pro) is for use for evaluation purposes only and must not be
incorporated into any other device or system.
Important
Important
Important
This equipment complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation (FCC
15.19).
The internal / external antenna(s) used for this mobile transmitter must provide a separation distance of at
least 20cm from all persons and must not be colocated or operating in conjunction with any other antenna or
transmitter.
Installers must be provided with antenna installation instructions and transmitter operating conditions for
satisfying RF exposure compliance. This device is approved as a mobile device with respect to RF exposure
compliance, and may only be marketed to OEM installers. Use in portable exposure conditions (FCC 2.1093)
requires separate equipment authorization.
Modifications not expressly approved by this company could void the user's authority to operate
this equipment (FCC section 15.21).
This equipment has been tested and found to comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment.
This equipment generates, uses, and can radiate radio frequency energy and, if not installed
and used in accordance with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at his own expense
(FCC section 15.105).
6.2 European Union (ETSI)
The SAM R21 Xplained Pro Evaluation kits has been certified for use in European Union countries. A
Declaration of Conformity must be issued for each of these standards and kept on file as described in Annex II
of the R&TTE Directive.
Furthermore, the manufacturer must maintain a copy of the modules' documentation and ensure the final
product does not exceed the specified power ratings, antenna specifications, and/or installation requirements
as specified in the user manual. If any of these specifications are exceeded in the final product, a submission
must be made to a notified body for compliance testing to all required standards.
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Important
The 'CE' marking must be affixed to a visible location on the OEM product. The CE mark shall
consist of the initials "CE" taking the following form:
● The CE marking must have a height of at least 5mm except where this is not possible on
account of the nature of the apparatus.
● The CE marking must be affixed visibly, legibly, and indelibly.
More detailed information about CE marking requirements you can find at "DIRECTIVE 1999/5/
EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL" on 9 March 1999 at section 12.
6.3 Canada (IC)
This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to the
following two conditions: (1) this device may not cause interference, and (2) this device must accept any
interference, including interference that may cause undesired operation of the device.
Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts
de licence. L'exploitation est autorisée aux deux conditions suivantes: (1) l'appareil ne doit pas produire
de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le
brouillage est susceptible d'en compromettre le fonctionnement.
This equipment complies with radio frequency exposure limits set forth by Industry Canada for an uncontrolled
environment. This equipment should be installed and operated with minimum distance 20cm between the
device and the user or bystanders.
Cet équipement est conforme aux limites d'exposition aux radiofréquences définies par Industrie Canada
pour un environnement non contrôlé. Cet équipement doit être installé et utilisé avec un minimum de 20cm de
distance entre le dispositif et l'utilisateur ou des tiers
Important
Any changes or modifications not expressly approved by the party responsible for compliance
could void the user’s authority to operate the equipment.
6.4 List of Antennas Tested With This Product
Table 6-1. List of Tested Antennas
Antenna Number Make Model/Part # Antenna Gain
Important
Antenna 1 Johanson
Technology
Antenna 2 Techfun Co., Ltd M01-SS2 0dBi External Antenna
If professional users including, but not limited to Research and Development engineers wants to
configure the power settings higher than those specified in page 7 of the FCC test report number
19660076 001, they are advised to use the antenna / device only in a shielded room.
2450AT18D0100 1.5dBi Ceramic Antenna
Type of Antenna
(dBi)
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7. Hardware Revision History and Known Issues
7.1 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 six 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. The sticker on SAM R21
Xplained Pro shows the identifier and revision plain text as A09-nnnn\rr where nnnn is the identifier and rr is the
revision. A uniqly assigned MAC64 address in hex, FCC ID and IC id are also printed on the sticker. A serial
number string is embedded in the matrix-barcode.
The serial number string has the following format:
"nnnnrrssssssssss"
n = product identifier
r = revision
s = serial number
The kit identifier for SAM R21 Xplained Pro is 2127.
7.2 Revision 3
Revision 3 of SAM R21 Xplained Pro is the initial released version, there are no known issues.
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8. Document revision history
Document
Date Comment
revision
42243B 06/2014 Fixed RF switch control pin-mapping to be correct and updated
the Agency Certification chapter.
42243A 02/2014 Initial document release.
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9. Evaluation Board/Kit Important Notice
This evaluation board/kit is intended for use for FURTHER ENGINEERING, DEVELOPMENT,
DEMONSTRATION, 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 limitation, 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 appropriate 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 DAMAGES.
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.
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© 2014 Atmel Corporation. / Rev.: 42243B-MCU-06/2014
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