3.1 I/O Multiplexing


VQFN32 / TQFP32	VQFN28	SPDIP28 / SOIC28 / SSOP28	Pin name ^(1,2)	Special	ADC0	AC0	DAC0	ZCD3	USARTn	SPI0	TWI0⁽⁴⁾	TCA0	TCBn	TCD0	EVSYS	CCL-LUTn
30	26	22	PA0	XTALHF1 EXTCLK					0,TxD	MOSI⁽³⁾	SDA(H)⁽³⁾	WO0				0,IN0
31	27	23	PA1	XTALHF2					0,RxD	MISO⁽³⁾	SCL(H)⁽³⁾	WO1				0,IN1
32	28	24	PA2	TWI Fm+	AIN22				0,XCK 0,TxD⁽³⁾		SDA(H)	WO2	0,WO		EVOUTA	0,IN2
1	1	25	PA3	TWI Fm+	AIN23				0,XDIR 0,RxD⁽³⁾		SCL(H)	WO3	1,WO			0,OUT
2	2	26	PA4		AIN24				0,TxD⁽³⁾	MOSI		WO4		WOA
3	3	27	PA5		AIN25				0,RxD⁽³⁾	MISO		WO5		WOB
4	4	28	PA6		AIN26				0,XCK⁽³⁾	SCK				WOC		0,OUT⁽³⁾
5	5	1	PA7	CLKOUT	AIN27	OUT		ZCOUT	0,XDIR⁽³⁾	SS				WOD	EVOUTA⁽³⁾
6	6	2	PC0		AIN28⁽⁶⁾				1,TxD	SCK⁽³⁾ MOSI⁽³⁾		WO0⁽³⁾	2,WO			1,IN0
7	7	3	PC1		AIN29⁽⁶⁾				1,RxD 0,TxD⁽³⁾	SS⁽³⁾ MISO⁽³⁾ MOSI⁽³⁾		WO1⁽³⁾				1,IN1
8	8	4	PC2	TWI Fm+	AIN30⁽⁶⁾	AINN3⁽⁶⁾		ZCIN	1,XCK 0,RxD⁽³⁾	SCK⁽³⁾ MISO⁽³⁾	SDA(C) SDA(H)⁽³⁾	WO2⁽³⁾			EVOUTC	1,IN2
9	9	5	PC3	TWI Fm+	AIN31⁽⁶⁾	AINP4⁽⁶⁾			1,XDIR 0,XCK⁽³⁾	SS⁽³⁾ SCK⁽³⁾	SCL(C) SCL(H)⁽³⁾	WO3⁽³⁾				1,OUT
10	10	6	VDDIO2
11	11	7	PD1		AIN1							WO1⁽³⁾				2,IN1
12	12	8	PD2		AIN2	AINP0						WO2⁽³⁾			EVOUTD	2,IN2
13	13	9	PD3		AIN3	AINN0						WO3⁽³⁾				2,OUT
14	14	10	PD4		AIN4				0,TxD⁽³⁾	MOSI⁽³⁾		WO4⁽³⁾		WOC⁽³⁾
15	15	11	PD5		AIN5				0,RxD⁽³⁾	MISO⁽³⁾		WO5⁽³⁾		WOD⁽³⁾
16	16	12	PD6		AIN6	AINP3	VOUT		0,XCK⁽³⁾ 1,TxD⁽³⁾	SCK⁽³⁾						2,OUT⁽³⁾
17	17	13	PD7	VREFA	AIN7	AINN2			0,XDIR⁽³⁾ 1,RxD⁽³⁾	SS⁽³⁾					EVOUTD⁽³⁾
18	18	14	VDD
19	19	15	GND
20	20	16	PF0	XTAL32K1	AIN16							WO0⁽³⁾		WOA⁽³⁾		3,IN0
21	21	17	PF1	XTAL32K2	AIN17							WO1⁽³⁾		WOB⁽³⁾		3,IN1
22			PF2		AIN18							WO2⁽³⁾		WOC⁽³⁾	EVOUTF	3,IN2
23			PF3		AIN19							WO3⁽³⁾		WOD⁽³⁾		3,OUT
24			PF4		AIN20							WO4⁽³⁾	0,WO⁽³⁾
25			PF5		AIN21							WO5⁽³⁾	1,WO⁽³⁾
26	22	18	PF6⁽⁵⁾	RESET
27	23	19	PF7	UPDI						SS⁽³⁾					EVOUTF⁽³⁾
28	24	20	VDD
29	25	21	GND

Note:

The pin names are Pxn type, with x being the PORT instance (A, B, C, ...) and n, the pin number. The notation for signals is PORTx_PINn. All pins can be used as event input.
All pins can be used for external interrupt.
Alternate pin positions. Refer to the PORTMUX - Port Multiplexer section for selecting the alternate positions.
The TWI pins that can be used as host or client are marked H. The pins with client-only are marked C.
Input-only.
ADC and AC inputs are available on MVIO pins (PORTC) if the MVIO is disabled in the SYSCFG1.MVSYSCFG fuse setting.