4.2.1 Xplained Pro Standard Extension Headers

The ATtiny3217 Xplained Pro headers EXT1 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 are based on the standard extension header specified in the table below. The headers have a pitch of 2.54 mm.

Table 4-1. Extension Header EXT1
EXT1 Pin	ATtiny3217 Pin	Function	Shared Functionality
1 [ID]	-	-	Communication line to the ID chip on an extension board
2 [GND]	-	-	Ground
3 [ADC(+)]	PA6	AIN6	QTouch Button 1
4 [ADC(-)]	PA7	AIN7	QTouch Button 2
5 [GPIO1]	PB7	GPIO	-
6 [GPIO2]	PB4	GPIO	LED0
7 [PWM(+)]	PB0	TC/W0	-
8 [PWM(-)]	PB1	TC/W1	-
9 [IRQ/GPIO]	PA5	IRQ/GPIO	-
10 [SPI_SS_B/GPIO]	PA4	GPIO	-
11 [I²C_SDA]	PA1	I²C SDA	EXT3 and EDBG I²C
12 [I²C_SCL]	PA2	I²C SCL	EXT3 and EDBG I²C
13 [USART_RX]	PB3	UART RX	EXT3, EDBG CDC, and Crystal ⁽¹⁾
14 [USART_TX]	PB2	UART TX	EXT3, EDBG CDC, and Crystal ⁽¹⁾
15 [SPI_SS_A]	PC3	SPI SS	-
16 [SPI_MOSI]	PC2	SPI MOSI	EXT3 and EDBG SPI
17 [SPI_MISO]	PC1	SPI MISO	EXT3 and EDBG SPI
18 [SPI_SCK]	PC0	SPI SCK	EXT3 and EDBG SPI
19 [GND]	-	-	Ground
20 [VCC]	-	-	Power for extension board

1) Not connected by default, see Connecting the 32.768 kHz Crystal for more information.

Note: Signal functions in italic use alternative pin location. These have to be configured in the PORTMUX register of the device.

Table 4-2. Extension Header EXT3
EXT3 Pin	ATtiny3217 Pin	Function	Shared Functionality
1 [ID]	-	-	Communication line to the ID chip on an extension board
2 [GND]	-	-	Ground
3 [ADC(+)]	-	-
4 [ADC(-)]	-	-
5 [GPIO1]	PC5	GPIO	SW1 and UPDI debug connector
6 [GPIO2]	-	-
7 [PWM(+)]	-	-
8 [PWM(-)]	-	-
9 [IRQ/GPIO]	PB6	IRQ/GPIO	EDBG DGI
10 [SPI_SS_B/GPIO]	PB5	GPIO	SW0 and EDBG DGI
11 [I²C_SDA]	PA1	I²C SDA	EXT1 and EDBG I²C
12 [I²C_SCL]	PA2	I²C SCL	EXT1 and EDBG I²C
13 [USART_RX]	PB3	UART RX	EXT1, EDBG CDC, and Crystal ⁽¹⁾
14 [USART_TX]	PB2	UART TX	EXT1, EDBG CDC, and Crystal ⁽¹⁾
15 [SPI_SS_A]	PA3	GPIO / SPI_SS	-
16 [SPI_MOSI]	PC2	SPI MOSI	EXT1 and EDBG SPI
17 [SPI_MISO]	PC1	SPI MISO	EXT1 and EDBG SPI
18 [SPI_SCK]	PC0	SPI SCK	EXT1 and EDBG SPI
19 [GND]	-	-	Ground
20 [VCC]	-	-	Power for extension board

1) Not connected by default, see Connecting the 32.768 kHz Crystal for more information.

Note: Signal functions in italic use alternative pin location. These have to be configured in the PORTMUX register of the device.