User manual

Atmel SAM D21 Xplained Pro [USER GUIDE]
42220A-MCU-02/2014
8
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 D21 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 D21 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)