Pin number

Name

Description

15

SPI_SS_A

Slave select for SPI. Should preferably be unique.

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 any 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 when using the 3.3V pin.

Table 3-5. Xplained Pro Power Header

Pin number

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 supply for the kit)

Atmel SAM R21 Xplained Pro [USER GUIDE]

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

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