6.1 Multiplexed Signals

Each pin is by default controlled by the PORT as a general purpose I/O and alternatively it can be assigned a different peripheral functions. To enable a peripheral function on a pin, the Peripheral Multiplexer Enable bit in the Pin Configuration register corresponding to that pin (PINCFGn.PMUXEN, n = 0-31) in the PORT must be written to '1'. The selection of peripheral function A to I is done by writing to the Peripheral Multiplexing Odd and Even bits in the Peripheral Multiplexing register (PMUXn.PMUXE/O) of the PORT.

This table describes the peripheral signals multiplexed to the PORT I/O pins.

Table 6-1. PORT Function Multiplexing
Function	-				A	B					C	D	E	F	G	H	I
Type	L22G⁽⁵⁾	L22J	L22N	Pad Name	EIC	ANAREF	ADC	AC	PTC	SLCD	SERCOM⁽⁶⁾	SERCOM⁽⁶⁾	TC/TCC	TCC/RTC	COM/RTC	AC/GCLK	CCL
Battery backup	1	1	1	PA00	EIC/EXTINT[0]							SERCOM1/PAD[0]
	2	2	2	PA01	EIC/EXTINT[1]							SERCOM1/PAD[1]
			3	PC00	EIC/EXTINT[8]		ADC/AIN[16]								RTC/IN[3]
			4	PC01	EIC/EXTINT[9]		ADC/AIN[17]								RTC/IN[4]
			5	PC02	EIC/EXTINT[10]		ADC/AIN[18]		PTC/XY[6]
			6	PC03	EIC/EXTINT[11]		ADC/AIN[19]		PTC/XY[7]
	3	3	7	PA02	EIC/EXTINT[2]	ADC/VREFB	ADC/AIN[0]	AC/AIN[0]	PTC/XY[8]						RTC/IN[2]
	4	4	8	PA03	EIC/EXTINT[3]	ADC/VREFA	ADC/AIN[1]	AC/AIN[1]	PTC/XY[9]
		5	9	PB04	EIC/EXTINT[4]		ADC/AIN[12]	AC/AIN[2]	PTC/XY[10]
		6	10	PB05	EIC/EXTINT[5]		ADC/AIN[13]	AC/AIN[3]	PTC/XY[11]
		9	13	PB06	EIC/EXTINT[6]		ADC/AIN[14]		PTC/XY[12]	SLCD/LP[0]							CCL/IN[6]
		10	14	PB07	EIC/EXTINT[7]		ADC/AIN[15]		PTC/XY[13]	SLCD/LP[1]							CCL/IN[7]
	7	11	15	PB08	EIC/EXTINT[8]		ADC/AIN[2]		PTC/XY[14]	SLCD/LP[2]		SERCOM3/PAD[0]	TC/0/WO[0]				CCL/IN[8]
	8	12	16	PB09	EIC/EXTINT[9]		ADC/AIN[3]		PTC/XY[15]	SLCD/LP[3]		SERCOM3/PAD[1]	TC/0/WO[1]				CCL/OUT[2]
	9	13	17	PA04	EIC/EXTINT[4]		ADC/AIN[4]		PTC/X[24]	SLCD/LP[4]		SERCOM0/PAD[0]	TCC/WO[0]				CCL/IN[0]
	10	14	18	PA05	EIC/EXTINT[5]		ADC/AIN[5]		PTC/X[25]	SLCD/LP[5]		SERCOM0/PAD[1]	TCC/WO[1]				CCL/IN[1]
	11	15	19	PA06	EIC/EXTINT[6]		ADC/AIN[6]		PTC/X[26]	SLCD/LP[6]		SERCOM0/PAD[2]					CCL/IN[2]
	12	16	20	PA07	EIC/EXTINT[7]		ADC/AIN[7]		PTC/X[27]	SLCD/LP[7]		SERCOM0/PAD[3]					CCL/OUT[0]
			21	PC05	EIC/EXTINT[13]				PTC/XY[4]	SLCD/LP[8]
			22	PC06	EIC/EXTINT[14]				PTC/XY[5]	SLCD/LP[9]
			23	PC07	EIC/EXTINT[15]					SLCD/LP[10]
	13	17	26	PA08	EIC/NMI				PTC/XY[3]	SLCD/LP[11]	SERCOM0/PAD[0]	SERCOM4/PAD[0]	TCC/WO[0]				CCL/IN[3]
	14	18	27	PA09	EIC/EXTINT[9]				PTC/XY[2]	SLCD/LP[12]	SERCOM0/PAD[1]	SERCOM4/PAD[1]	TCC/WO[1]				CCL/IN[4]
	15	19	28	PA10	EIC/EXTINT[10]				PTC/XY[1]	SLCD/LP[13]	SERCOM0/PAD[2]	SERCOM4/PAD[2]		TCC/WO[2]		GCLK/IO[4]	CCL/IN[5]
	16	20	29	PA11	EIC/EXTINT[11]				PTC/XY[0]	SLCD/LP[14]	SERCOM0/PAD[3]	SERCOM4/PAD[3]		TCC/WO[3]			CCL/OUT[1]
			30	PC08	EIC/EXTINT[0]					SLCD/LP[15]
			31	PC09	EIC/EXTINT[1]					SLCD/LP[16]
			32	PC10	EIC/EXTINT[2]					SLCD/LP[17]	SERCOM1/PAD[2]
			33	PC11	EIC/EXTINT[3]					SLCD/LP[18]	SERCOM1/PAD[3]
			34	PC12	EIC/EXTINT[4]					SLCD/LP[19]	SERCOM1/PAD[0]
			35	PC13	EIC/EXTINT[5]					SLCD/LP[20]	SERCOM1/PAD[1]
	19	23	38	VLCD
	20	24	39	PB11	EIC/EXTINT[11]					SLCD/LP[21]		SERCOM3/PAD[3]	TC/1/WO[1]	TCC/WO[5]			CCL/OUT[1]
I2C: full Fm+. Limited currents for Sm, Fm		25	40	PB12	EIC/EXTINT[12]					SLCD/LP[22]	SERCOM3/PAD[0]		TC/0/WO[0]	TCC/WO[6]
I2C: full Fm+. Limited currents for Sm, Fm		26	41	PB13	EIC/EXTINT[13]					SLCD/LP[23]	SERCOM3/PAD[1]		TC/0/WO[1]	TCC/WO[7]
		27	42	PB14	EIC/EXTINT[14]					SLCD/LP[24]	SERCOM3/PAD[2]		TC/1/WO[0]			GCLK/IO[0]	CCL/IN[9]
		28	43	PB15	EIC/EXTINT[15]					SLCD/LP[25]	SERCOM3/PAD[3]		TC/1/WO[1]			GCLK/IO[1]	CCL/IN[10]
			44	PC14	EIC/EXTINT[6]					SLCD/LP[26]
			45	PC15	EIC/EXTINT[7]					SLCD/LP[27]
I2C: Sm, Fm, Fm+	21	29	46	PA12	EIC/EXTINT[12]					SLCD/LP[28]	SERCOM4/PAD[0]	SERCOM3/PAD[0]		TCC/WO[6]		AC/CMP[0]
I2C: Sm, Fm, Fm+	22	30	47	PA13	EIC/EXTINT[13]					SLCD/LP[29]	SERCOM4/PAD[1]	SERCOM3/PAD[1]		TCC/WO[7]		AC/CMP[1]
	23	31	48	PA14	EIC/EXTINT[14]					SLCD/LP[30]	SERCOM4/PAD[2]	SERCOM3/PAD[2]		TCC/WO[4]		GCLK/IO[0]
	24	32	49	PA15	EIC/EXTINT[15]					SLCD/LP[31]	SERCOM4/PAD[3]	SERCOM3/PAD[3]		TCC/WO[5]		GCLK/IO[1]
	25	35	52	PA16	EIC/EXTINT[0]				PTC/X[28]	SLCD/LP[32]	SERCOM1/PAD[0]	SERCOM2/PAD[0]		TCC/WO[6]		GCLK/IO[2]	CCL/IN[0]
	26	36	53	PA17	EIC/EXTINT[1]				PTC/X[29]	SLCD/LP[33]	SERCOM1/PAD[1]	SERCOM2/PAD[1]		TCC/WO[7]		GCLK/IO[3]	CCL/IN[1]
	27	37	54	PA18	EIC/EXTINT[2]				PTC/X[30]	SLCD/LP[34]	SERCOM1/PAD[2]	SERCOM2/PAD[2]		TCC/WO[2]		AC/CMP[0]	CCL/IN[2]
	28	38	55	PA19	EIC/EXTINT[3]				PTC/X[31]	SLCD/LP[35]	SERCOM1/PAD[3]	SERCOM2/PAD[3]		TCC/WO[3]		AC/CMP[1]	CCL/OUT[0]
			56	PC16	EIC/EXTINT[8]					SLCD/LP[36]
			57	PC17	EIC/EXTINT[9]					SLCD/LP[37]
			58	PC18	EIC/EXTINT[10]					SLCD/LP[38]
			59	PC19	EIC/EXTINT[11]					SLCD/LP[39]
			60	PC20	EIC/EXTINT[12]					SLCD/LP[40]							CCL/IN[9]
			61	PC21	EIC/EXTINT[13]					SLCD/LP[41]							CCL/IN[10]
		39	64	PB16	EIC/EXTINT[0]					SLCD/LP[42]	SERCOM5/PAD[0]		TC/2/WO[0]	TCC/WO[4]		GCLK/IO[2]	CCL/IN[11]
		40	65	PB17	EIC/EXTINT[1]					SLCD/LP[43]	SERCOM5/PAD[1]		TC/2/WO[1]	TCC/WO[5]		GCLK/IO[3]	CCL/OUT[3]
			66	PB18	EIC/EXTINT[2]					SLCD/LP[44]	SERCOM5/PAD[2]	SERCOM3/PAD[2]		TCC/WO[0]
			67	PB19	EIC/EXTINT[3]					SLCD/LP[45]	SERCOM5/PAD[3]	SERCOM3/PAD[3]		TCC/WO[1]
			68	PB20	EIC/EXTINT[4]					SLCD/LP[46]	SERCOM3/PAD[0]	SERCOM5/PAD[0]		TCC/WO[2]
			69	PB21	EIC/EXTINT[5]					SLCD/LP[47]	SERCOM3/PAD[1]	SERCOM5/PAD[1]		TCC/WO[3]
	29	41	70	PA20	EIC/EXTINT[4]				PTC/XY[16]	SLCD/LP[48]	SERCOM0/PAD[0]	SERCOM2/PAD[2]	TC/3/WO[0]	TCC/WO[6]		GCLK/IO[4]
	30	42	71	PA21	EIC/EXTINT[5]				PTC/XY[17]	SLCD/LP[49]	SERCOM0/PAD[1]	SERCOM2/PAD[3]	TC/3/WO[1]	TCC/WO[7]
I2C: Sm, Fm, Fm+	31	43	72	PA22	EIC/EXTINT[6]				PTC/XY[18]	SLCD/LP[50]	SERCOM0/PAD[2]	SERCOM2/PAD[0]	TC/0/WO[0]	TCC/WO[4]			CCL/IN[6]
I2C: Sm, Fm, Fm+	32	44	73	PA23	EIC/EXTINT[7]				PTC/XY[19]	SLCD/LP[51]	SERCOM0/PAD[3]	SERCOM2/PAD[1]	TC/0/WO[1]	TCC/WO[5]	USB/SOF_1KHZ		CCL/IN[7]
	33	45	74	PA24	EIC/EXTINT[12]						SERCOM2/PAD[2]	SERCOM5/PAD[0]	TC/1/WO[0]	TCC/WO[0]	USB/DM		CCL/IN[8]
	34	46	75	PA25	EIC/EXTINT[13]						SERCOM2/PAD[3]	SERCOM5/PAD[1]	TC/1/WO[1]	TCC/WO[1]	USB/DP		CCL/OUT[2]
	37	49	78	PB22	EIC/EXTINT[6]						SERCOM0/PAD[2]	SERCOM5/PAD[2]	TC/3/WO[0]	TCC/WO[2]	USB/SOF_1KHZ	GCLK/IO[0]	CCL/IN[0]
	38	50	79	PB23	EIC/EXTINT[7]						SERCOM0/PAD[3]	SERCOM5/PAD[3]	TC/3/WO[1]	TCC/WO[3]		GCLK/IO[1]	CCL/OUT[0]
			80	PB24	EIC/EXTINT[8]						SERCOM0/PAD[0]	SERCOM4/PAD[0]		TCC/WO[6]		AC/CMP[0]
			81	PB25	EIC/EXTINT[9]						SERCOM0/PAD[1]	SERCOM4/PAD[1]		TCC/WO[7]		AC/CMP[1]
			82	PC24	EIC/EXTINT[0]						SERCOM0/PAD[2]	SERCOM4/PAD[2]	TC/2/WO[0]	TCC/WO[0]
			83	PC25	EIC/EXTINT[1]						SERCOM0/PAD[3]	SERCOM4/PAD[3]	TC/2/WO[1]	TCC/WO[1]
			84	PC26	EIC/EXTINT[2]								TC/3/WO[0]	TCC/WO[2]
			85	PC27	EIC/EXTINT[3]							SERCOM1/PAD[0]	TC/3/WO[1]	TCC/WO[3]			CCL/IN[4]
			86	PC28	EIC/EXTINT[4]				PTC/XY[20]			SERCOM1/PAD[1]		TCC/WO[4]			CCL/IN[5]
recommended for GCLK IO	39	51	87	PA27	EIC/EXTINT[15]				PTC/XY[21]					TCC/WO[5]		GCLK/IO[0]
	40	52	88	RESET_N
	45	57	93	PA30	EIC/EXTINT[10]				PTC/XY[22]			SERCOM1/PAD[2]			CORTEX_M0P/SWCLK	GCLK/IO[0]	CCL/IN[3]
	46	58	94	PA31	EIC/EXTINT[11]				PTC/XY[23]			SERCOM1/PAD[3]			SWDIO		CCL/OUT[1]
I2C: Sm, Fm, Fm+, Hs		59	95	PB30	EIC/EXTINT[14]						SERCOM1/PAD[0]	SERCOM5/PAD[0]	TCC/WO[0]
I2C: Sm, Fm, Fm+, Hs		60	96	PB31	EIC/EXTINT[15]						SERCOM1/PAD[1]	SERCOM5/PAD[1]	TCC/WO[1]
Battery backup		61	97	PB00	EIC/EXTINT[0]		ADC/AIN[8]				SERCOM3/PAD[2]	SERCOM5/PAD[2]	TC/3/WO[0]		RTC/IN[0]		CCL/IN[1]
		62	98	PB01	EIC/EXTINT[1]		ADC/AIN[9]				SERCOM3/PAD[3]	SERCOM5/PAD[3]	TC/3/WO[1]	RTC/IN[2]	RTC/OUT		CCL/IN[2]
	47	63	99	PB02	EIC/EXTINT[2]		ADC/AIN[10]				SERCOM3/PAD[0]	SERCOM5/PAD[0]	TC/2/WO[0]		RTC/IN[1]		CCL/OUT[0]
	48	64	100	PB03	EIC/EXTINT[3]		ADC/AIN[11]				SERCOM3/PAD[1]	SERCOM5/PAD[1]	TC/2/WO[1]

Note:

All analog pin functions are on peripheral function B. Peripheral function B must be selected to disable the digital control of the pin.
Only some pins can be used in SERCOM I²C mode. See the Type column for supported I²C modes.
- Sm: Standard mode, up to 100kHz
- Fm: Fast mode, up to 400kHz
- Fm+: Fast mode Plus, up to 1MHz
- Hs: High-speed mode, up to 3.4MHz
These pins are High Sink pins and have different properties than regular pins:
PA12, PA13, PA22, PA23, PA27, PA31, PB30, PB31.
Clusters of multiple GPIO pins are sharing the same supply pin.
The 49^th pin of the WLCSP49 package is an additional GND pin.
SAM L22N: SERCOM[0:5]. SAM L22G, L22J: SERCOM[0:3].