Atmel SAM R21 Xplained Pro User Manual
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. Using Limited Modular Certified Products ...... .... .... ........... .... .... 18
6.5. List of Antennas Tested With This Product . .... .... ....... .... .... ........ 19
7. Hardware Revision History and Known Issues ..................... 20
7.1. Identifying Product ID and Revision .. ........... .... .... ........... .... .... . 20
7.2. Revision 3 .. ........... .... .... ........... .... .... ....... .... .... ........... .... .... 20
8. Document revision history ..................................................... 21
9. Evaluation Board/Kit Important Notice .................................. 22
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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
3 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 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. 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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