User manual

Atmel SAM D20 Xplained Pro [USER GUIDE]

42102C-MCU-02/2014

Table 4-4. External 32.768kHz Crystal

Pin on SAM D20 Function

PA00 XIN32

PA01 XOUT32

4.2.2 Mechanical Buttons

SAM D20 Xplained Pro contains two mechanical buttons. One button is the RESET button connected to the

SAM D20 reset line and the other is a generic user configurable button. When a button is pressed it will drive

the I/O line to GND.

Table 4-5. Mechanical Buttons

Pin on SAM D20 Silkscreen text

RESETN RESET

PA15 SW0

4.2.3 LED

There is one yellow LED available on the SAM D20 Xplained Pro board that can be turned on and off. The LED

can be activated by driving the connected I/O line to GND.

Table 4-6. LED connections

Pin on SAM D20 LED

PA14 Yellow LED0

4.3 Embedded Debugger Implementation

SAM D20 Xplained Pro contains an Embedded Debugger (EDBG) that can be used to program and debug the

ATSAMD20J18A 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 D20

GPIOs. Atmel Studio can be used as a front end for the Embedded Debugger.

4.3.1 Serial Wire Debug

The Serial Wire Debug (SWD) use two pins to communicate with the target. For further information on how to

use the programming and debugging capabilities of the EDBG, see “Embedded Debugger” on page 6.

Table 4-7. SWD Connections

Pin on SAM D20 Function

PA30 SWD clock

PA31 SWD data

4.3.2 Virtual COM Port

The Embedded Debugger acts as a Virtual Com Port gateway by using one of the ATSAMD20J18A UARTs.

For further information on how to use the Virtual COM port see “Embedded Debugger” on page 6.

Table 4-8. Virtual COM Port Connections

Pin on SAM D20 Function

PA24 SERCOM3 PAD[2] UART TXD (SAM D20 TX line)

PA25 SERCOM3 PAD[3] UART RXD (SAM D20 RX line)

4.3.3 Atmel Data Gateway Interface

The Embedded Debugger features an Atmel Data Gateway Interface (DGI) by using either a SPI or I²C port.

The DGI can be used to send a variety of data from the SAM D20 to the host PC. For further information on

how to use the DGI interface see “Embedded Debugger” on page 6.

Table 4-9. DGI Interface Connections when using SPI

Pin on SAM D20 Function

PB31 SERCOM5 PAD[1] SPI SS (Slave select) (SAM D20 is Master)