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, which 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,

which are connected through a set of standardized headers and connectors. Each extension board has

an identification (ID) chip to uniquely identify which boards are connected to an Xplained Pro MCU board.

This information is used to present relevant user guides, application notes, datasheets, and example

code through Atmel Studio.

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 a Data

Gateway Interface (DGI).

Together with Atmel Studio, the EDBG debugger interface can program and debug the ATSAMR21G18A.

On SAM R21 Xplained Pro, the SWD interface is connected between the EDBG and the

ATSAMR21G18A.

The Virtual COM Port is connected to a UART on the ATSAMR21G18A and provides an easy way to

communicate with the target application through terminal software. It offers variable baud rate, parity, and

stop bit settings. Note that the settings on the ATSAMR21G18A must match the settings given in the

terminal software.

Info:  The virtual COM port in the EDBG requires the terminal software to set the data terminal

ready (DTR) signal to enable the UART pins connected to the ATSAMR21G18A. If the DTR

signal is not enabled the UART pins on the EDBG is kept in high-z (tristate) rendering the COM

port unusable. The DTR signal is set automatically by some terminal software, but it may have

to be manually enabled in your terminal.

The DGI consists of several physical interfaces for communication with the host computer.

Communication over the interfaces is 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. Atmel Data Visualizer is used to send and receive data through DGI.

The EDBG controls two LEDs on SAM R21 Xplained Pro; a power LED and a status LED. The table

below 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

when any communication

happens to the EDBG.

Bootloader mode (idle)

The power LED and the status LED blinks simultaneously.

Bootloader mode (firmware

upgrade)

The power LED and the status LED blinks in an alternating pattern.

Atmel SAM R21 Xplained Pro [USER GUIDE]

Atmel-42243D-SAM-R21-Xplained-Pro_User Guide-04/2016

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