4.1.1 Xplained Pro Standard Extension Headers
The SAM D21 Xplained Pro headers EXT1, EXT2, and EXT3 offer access to the I/O of the microcontroller in order to expand the board e.g. by connecting extensions to the board. These headers all comply with the standard extension header specified in Xplained Pro Standard Extension Header. All headers have a pitch of 2.54mm.
Pin on EXT1 | SAM D21 pin | Function | Shared functionality |
---|---|---|---|
1 [ID] | - | - | Communication line to ID chip on extension board. |
2 [GND] | - | - | GND |
3 [ADC(+)] | PB00 | AIN[8] | |
4 [ADC(-)] | PB01 | AIN[9] | |
5 [GPIO1] | PB06 | GPIO | |
6 [GPIO2] | PB07 | GPIO | |
7 [PWM(+)] | PB02 | TC6/WO[0] | |
8 [PWM(-)] | PB03 | TC6/WO[1] | |
9 [IRQ/GPIO] | PB04 | EXTINT[4] | |
10 [SPI_SS_B/GPIO] | PB05 | GPIO | |
11 [TWI_SDA] | PA08 | SERCOM2 PAD[0] I²C SDA | EXT2, EXT3, and EDBG |
12 [TWI_SCL] | PA09 | SERCOM2 PAD[1] I²C SCL | EXT2, EXT3, and EDBG |
13 [USART_RX] | PB09 | SERCOM4 PAD[1] UART RX(1) | |
14 [USART_TX] | PB08 | SERCOM4 PAD[0] UART TX(1) | |
15 [SPI_SS_A] | PA05 | SERCOM0 PAD[1] SPI SS | |
16 [SPI_MOSI] | PA06 | SERCOM0 PAD[2] SPI MOSI | |
17 [SPI_MISO] | PA04 | SERCOM0 PAD[0] SPI MISO | |
18 [SPI_SCK] | PA07 | SERCOM0 PAD[3] SPI SCK | |
19 [GND] | - | - | GND |
20 [VCC] | - | - | VCC |
Note:
- The SERCOM4 module is shared between EXT1, 2, and 3 UART's, but uses different pins on EXT1 and EXT2/3.
Pin on EXT2 | SAM D21 pin | Function | Shared functionality |
---|---|---|---|
1 [ID] | - | - | Communication line to ID chip on extension board. |
2 [GND] | - | - | GND |
3 [ADC(+)] | PA10 | AIN[18] | |
4 [ADC(-)] | PA11 | AIN[19] | |
5 [GPIO1] | PA20 | GPIO | |
6 [GPIO2] | PA21 | GPIO | |
7 [PWM(+)] | PB12 | TC4/WO[0] | |
8 [PWM(-)] | PB13 | TC4/WO[1] | |
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 |
Note:
- The SERCOM4 module is shared between EXT1, 2, and 3 UART's, but uses different pins on EXT1 and EXT2/3.
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 | TCC2/WO[0] | |
8 [PWM(-)] | PA13 | TCC2/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 |
Note:
- PA03 can be used by USB ID or EXT3 PIN4 by changing the position of the jumper JS300 on J307.
- 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 0Ω resistor R314 to R313.
- The SERCOM4 module is shared between EXT1, 2, and 3 UART's, but uses different pins on EXT1 and EXT2/3.