Multiplexed Signals

Table 1. PORT Function Multiplexing
VQFN 24-Pin	Pin Name ^(1,2)	Other/Special	ADC0	PTC⁽⁴⁾	AC0	DAC	USART0	SPI0	TWI0	TCA0	TCB0	TCD0	CCL
23	PA0	RESET/ UPDI	AIN0										LUT0-IN0
24	PA1		AIN1				TxD⁽³⁾	MOSI	SDA⁽³⁾				LUT0-IN1
1	PA2	EVOUT0	AIN2				RxD⁽³⁾	MISO	SCL⁽³⁾				LUT0-IN2
2	PA3	EXTCLK	AIN3				XCK⁽³⁾	SCK		WO3
3	GND
4	VDD
5	PA4		AIN4	X0/Y0			XDIR⁽³⁾	SS		WO4		WOA	LUT0-OUT
6	PA5		AIN5	X1/Y1	OUT					WO5	WO	WOB
7	PA6		AIN6	X2/Y2	AINN0	OUT
8	PA7		AIN7	X3/Y3	AINP0								LUT1-OUT
9	PB7
10	PB6
11	PB5	CLKOUT	AIN8		AINP1					WO2⁽³⁾
12	PB4		AIN9		AINN1					WO1⁽³⁾			LUT0-OUT⁽³⁾
13	PB3	TOSC1					RxD			WO0⁽³⁾
14	PB2	TOSC2, EVOUT1					TxD			WO2
15	PB1		AIN10	X4/Y4			XCK		SDA	WO1
16	PB0		AIN11	X5/Y5			XDIR		SCL	WO0
17	PC0							SCK⁽³⁾			WO⁽³⁾	WOC
18	PC1							MISO⁽³⁾				WOD	LUT1-OUT⁽³⁾
19	PC2	EVOUT2						MOSI⁽³⁾
20	PC3							SS⁽³⁾		WO3⁽³⁾			LUT1-IN0
21	PC4									WO4⁽³⁾			LUT1-IN1
22	PC5									WO5⁽³⁾			LUT1-IN2

Note:

1.Pin names are of type Pxn, with x being the PORT instance (A, B) and n the pin number. Notation for signals is PORTx_PINn. All pins can be used as event input.
2.All pins can be used for external interrupt, where pins Px2 and Px6 of each port have full asynchronous detection.
3. Alternate pin positions. For selecting the alternate positions, refer to the PORTMUX documentation.
4.PTC is only available in devices with 8 KB Flash (ATtiny817). Every PTC line can be configured as X- or Y-line.