Atmel SAM R21 Xplained Pro [USER GUIDE]
42243A-MCU-02/2014
14
Note
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.
Important
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.
