User manual

Atmel SAM D21 Xplained Pro [USER GUIDE]
42220A-MCU-02/2014
11
Pin on EXT2 SAM D21 pin Function Shared functionality
9 [IRQ/GPIO] PB14 EXTINT[14]
10 [SPI_SS_B/GPIO] PB15 GPIO
11 [TWI_SDA] PA08 SERCOM2 PAD[0] I²C SDA EXT1, EXT3, and EDBG
12 [TWI_SCL] PA09 SERCOM2 PAD[1] I²C SCL EXT1, EXT3, and EDBG
13 [USART_RX] PB11 SERCOM4 PAD[1] UART RX
1
EXT3
14 [USART_TX] PB10 SERCOM4 PAD[0] UART TX
1
EXT3
15 [SPI_SS_A] PA17 SERCOM1 PAD[1] SPI SS
16 [SPI_MOSI] PA18 SERCOM1 PAD[2] SPI MOSI
17 [SPI_MISO] PA16 SERCOM1 PAD[0] SPI MISO
18 [SPI_SCK] PA19 SERCOM1 PAD[3] SPI SCK
19 [GND] - - GND
20 [VCC] - - VCC
Notes:
1
The SERCOM4 module is shared between EXT1, 2 and 3 UART's, but uses different pins on EXT1 and EXT2/3.
Table 4-3. Extension Header EXT3
Pin on EXT3 SAM D21 pin Function Shared functionality
1 [ID] - - Communication line to ID chip
on extension board.
2 [GND] - - GND
3 [ADC(+)] PA02 AIN[0]
4 [ADC(-)] PA03 AIN[1]
1
USB ID
5 [GPIO1] PB30 GPIO Onboard LED0
6 [GPIO2] PA15 GPIO Onboard SW0
7 [PWM(+)] PA12 TC2/WO[0]
8 [PWM(-)] PA13 TC2/WO[1]
2
Serial Flash SS
9 [IRQ/GPIO] PA28 EXTINT[8]
10 [SPI_SS_B/GPIO] PA27 GPIO
11 [TWI_SDA] PA08 SERCOM2 PAD[0] I²C SDA EXT1, EXT2, and EDBG
12 [TWI_SCL] PA09 SERCOM2 PAD[1] I²C SCL EXT1, EXT2, and EDBG
13 [USART_RX] PB11 SERCOM4 PAD[1] UART RX
3
14 [USART_TX] PB10 SERCOM4 PAD[0] UART TX
3
15 [SPI_SS_A] PB17 SERCOM5 PAD[1] SPI SS
16 [SPI_MOSI] PB22 SERCOM5 PAD[2] SPI MOSI EDBG and Serial Flash
17 [SPI_MISO] PB16 SERCOM5 PAD[0] SPI MISO EDBG and Serial Flash
18 [SPI_SCK] PB23 SERCOM5 PAD[3] SPI SCK EDBG and Serial Flash
19 [GND] - - GND
20 [VCC] - - VCC
Notes:
1
PA03 can be used by USB ID or EXT3 PIN4 by changing the position of the jumper JS300 on J307.
2
PA13 is by default connected to the Serial Flash SS line and is disconnected from the EXT3 PIN8. This can be changed by
moving the 0-Ohm resistor R314 to R313.
3
The SERCOM4 module is shared between EXT1, 2 and 3 UART's, but uses different pins on EXT1 and EXT2/3.
4.2 Peripherals
4.2.1 Crystal
The SAM D21 Xplained Pro kit contains one crystals that can be used as clock source for the SAM D21 device.
The crystal has a cut-strap next to it that can be used to measure the oscillator safety factor. This is done by