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3.9.3 DisplayPort Audio...................................................................................................................... 18
3.10 DC-power and Battery Power ............................................................................................................ 19
3.11 DC power Measurements................................................................................................................... 19
3.12 Buttons ............................................................................................................................................... 19
3.13 External Fan connection .................................................................................................................... 19
3.14 UART ................................................................................................................................................. 19
3.15 JTAG (NA) ........................................................................................................................................ 19
3.16 System and user LEDs ....................................................................................................................... 20
3.17 Expansion Connector ......................................................................................................................... 20
3.18 Additional Functionality .................................................................................................................... 20
3.18.1 Ethernet Connector .................................................................................................................... 20
3.18.2 Inertial Sensors .......................................................................................................................... 21
3.18.3 DIP Switch ................................................................................................................................. 21
3.18.4 Extra Low Speed Expansion Connector .................................................................................... 22
3.18.5 Extra High Speed Expansion Connectors .................................................................................. 22
4 Low speed Expansion connector ....................................................................................................................... 23
4.1 Primary Low Speed Expansion Connector: LS1 ............................................................................... 23
4.1.1 UART ......................................................................................................................................... 24
4.1.2 I2C ............................................................................................................................................. 25
4.1.3 GPIO .......................................................................................................................................... 25
4.1.4 SPI.............................................................................................................................................. 25
4.1.5 PCM/I2S .................................................................................................................................... 26
4.1.6 Power and Reset......................................................................................................................... 26
4.1.7 Power Supplies .......................................................................................................................... 26
4.2 Secondary Low Speed Connector: LS2 ............................................................................................. 27
4.2.1 Audio ......................................................................................................................................... 29
4.2.2 Stereo speaker ............................................................................................................................ 29