Header pinout¶

• All pins can be accessed by other HATs with a stacking header.

• The MacArthur HAT uses the red pins , which can also be used by other HATs but only one at a time.

• The MacArthur HAT uses the green pins, which can also be used by other HATs at the same time.

• The MacArthur HAT does not use the black pins.

Feature	Interface	BCM	Pins	BCM	Interface	Feature
		3.3V	1 - 2	5V
I2C sensors compass, heel, trim	I2C SDA	GPIO2	3 - 4	5V
I2C sensors compass, heel, trim	I2C SCL	GPIO3	5 - 6	GND
NMEA 0183 TX1*	UART3 TX	GPIO4	7 - 8	GPIO14	UART0 TX	MAIANA AIS dAISy HAT Pypilot controller
		GND	9 - 10	GPIO15	UART0 RX	MAIANA AIS dAISy HAT Pypilot controller
		GPIO17	11 - 12	GPIO18
		GPIO27	13 - 14	GND
		GPIO22	15 - 16	GPIO23
		3.3V	17 - 18	GPIO24
NMEA 2000	SPI0 MOSI	GPIO10	19 - 20	GND
NMEA 2000	SPI0 MISO	GPIO9	21 - 22	GPIO25	GPIO	NMEA 2000 INT
NMEA 2000	SPI0 SCLK	GPIO11	23 - 24	GPIO8
		GND	25 - 26	GPIO7	SPI0 CE1	NMEA 2000 CS
		GPIO0	27 - 28	GPIO1
NMEA 0183 RX1*	UART3 RX	GPIO5	29 - 30	GND
		GPIO6	31 - 32	GPIO12	UART5 TX	NMEA 0183 TX2*
NMEA 0183 RX2*	UART5 RX	GPIO13	33 - 34	GND
1-Wire sensors GPIO	1W/GPIO	GPIO19	35 - 36	GPIO16
Power Off	GPIO	GPIO26	37 - 38	GPIO20	GPIO	Seatalk1 RX GPIO
		GND	39 - 40	GPIO21	GPIO	Shutdown

*If you want to use these GPIOs for other purposes, note that they all have pull-up resistors.