Pixhawk Payload Bus

The Pixhawk Payload Bus (PPB) Adapter Board board is used to break out the Skynode payload interface (J10) into connectors/pinouts that are compatible with the Pixhawk Payload Bus (PPB) Standard.

It is recommended to connect payloads to the PPB interface and use the standalone USB and Ethernet ports on Skynode for other peripherals and ground station links.

1MB

Payload Adapter Board.stl

3D model mockup

Schematic

249KB

PPB-Adapter_RC03.pdf

pdf

PPB Adapter RC03

Connectors

ID	Name	Connector	Description
J1	UART & I2C	JST GH 6-pin SM06B-GHS-TB	UART4 and I2C from FMU
J2	CAN 1	JST GH 3-pin SM02B-GHS-TB	CAN from FMU
J3	GPIOs	JST GH 6-pin SM06B-GHS-TB	FMU CH 7 and CH 8, FMU CAP and one GPIO from MC
J4	Ethernet	RJ45 socket
J5	USB	USB Type-C
J6	Power	Molex Micro-Lock Plus 5055670681	Power for FMU peripherals (J1, J2 and J3)
J7	Power	Pads	Parallel input to J6
J10	PPB	SFV30R-3STBE1HLF	FFC interface to Skynode (J10)

Pinouts

GPS 2 (J1)

Pin	Name	Dir	Lvl	Function
1	VDD_5V_PERIPH_SW		5V	5V supply for peripherals, enabled with VDD_5V_PERIPH
2	FMU_UART4_TX	OUT	3.3V	Pixhawk Payload Bus TX
3	FMU_UART4_RX	IN	3.3V	Pixhawk Payload Bus RX
4	FMU_I2C3_SCL	I/O	3.3V
5	FMU_I2C3_SDA	I/O	3.3V
6	GND			Ground

I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.

CAN 1 (J2)

Pin	Name	Dir	Lvl	Function
1	VDD_5V_PERIPH_SW		5V	5V supply for peripherals, enabled with VDD_5V_PERIPH
2	CAN1_P	I/O		FMU CAN 1
3	CAN1_N	I/O		FMU CAN 1
4	GND			Ground

CAN bus termination on Skynode changed in RC11. Prior to rev 11, Skynode has a 120Ω bus termination resistor inside, with no CAN termination on the breakout boards. This configuration assumed that Skynode was at the end of the bus. Rev 11 and onwards has the 120Ω bus termination resistor on the Adapter board, without built-in termination inside of Skynode. When designing a wire harness instead of using the breakout boards, usage of a 120Ω termination resistors at both ends of the bus is mandatory, following ISO 11898.

GPIO (J3)

Pin	Name	Dir	Lvl	Function
1	VDD_5V_PERIPH_SW		5V	5V supply for peripherals, enabled with VDD_5V_PERIPH
2	FMU_CH7	I/O	3.3V	FMU Channel 7
3	FMU_CH8	I/O	3.3V	FMU Channel 8
4	FMU_CAP1_AUX	IN	3.3V	Capture
5	COMP_GPIO5_IO20_1V8	I/O	1.8V	GPIO from mission computer
6	GND			Ground

Ethernet (J4)

Please refer to the official pinout specification for RJ45 connectors.

The Skynode ethernet interfaces are decoupled with capacitors. The maximum cable length inside the payload should not exceed 2m and all connected devices should have a common ground.

USB (J5)

Please refer to the official pinout specification for USB Type-C connectors. The supported data rate is USB 2.0 High-Speed (up to 480 Mbit/s)

Power (J6)

Pin	Name	Dir	Lvl	Function
1	VDD_5V_INPUT	IN	5V	5V power supply input
2	VDD_5V_INPUT	IN	5V	5V power supply input
3	FMU_I2C3_SCL	I/O	3.3V	FMU I2C SCL
4	FMU_I2C3_SDA	I/O	3.3V	FMU I2C SDA
5	GND			Ground
6	GND			Ground

I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.

Connecting the PPB Adapter Board

Skynode provides a single connector interface with all signals used in the Pixhawk Payload Bus on connector J10 and can be used with different mechanical designs.

The Skynode Evaluation Kit includes a small adapter board that converts the FFC interface of Skynode to standardized connectors for each interface. Connect the PPB interface on Skynode (J10) with the adapter board (J10) with the included 30-position FFC cable.

What you will need for this step:

1. Skynode Enterprise

2. Pixhawk Payload Adapter Board

3. 30-position FFC cable

4. Small tool, e.g. micro-screwdriver

The PPB connector (J10) is an FPC connector with slide lock (Part number SFV30R-3STBE1HLF, the same connector is installed on the PPB adapter board). The locking mechanism has to be pulled out before the cable is inserted.

Connect FFC cable to Skynode PPB Connector

To avoid damage to Skynode or connected peripherals, unplug the power source before continuing to connect the PPB Adapter Board.

1. In order to open the locking mechanism of the FPC connector, insert a small tool into the opening at the side of the connector.
2. Carefully pull the wing of the locking mechanism towards you and out of the enclosure.
3. Repeat the previous two steps on the left side and completely unlock the connector.
4. Next, insert the 30-position FFC cable into the connector. To do so, place the FFC cable on top of the locking latch with the contacts facing up and slide it into the connector.
5. To secure the cable into the connector, push the locking latch back into its closed position. Use the tool or your fingers to apply pressure on the both sides of the latch.

Connect FFC cable PPB Adapter Board

1. On the PPB adapter board, open the locking mechanism of the FPC connector and place the board next to Skynode.
2. Slide the FFC cable into the connector, the contacts are facing down on this side.
3. Close the locking mechanism by pushing back the latch (see arrows on the left).

Configuration

To star start an MAVLink instance on the Pixhawk Payload Bus, set the PX4 parameter MAV_2_CONFIG to EXT2.