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.
{% file src="../../../.gitbook/assets/Payload Adapter Board.stl" %} 3D model mockup {% endfile %}
Schematic
{% file src="../../../.gitbook/assets/PPB-Adapter_RC03.pdf" %} PPB Adapter RC03 {% endfile %}
Connectors
| ID | Name | Connector | Description |
|---|---|---|---|
| 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 |
|---|---|---|---|---|
| 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_SDA | I/O | 3.3V | |
| 5 | FMU_I2C3_SCL | I/O | ||
| 6 | GND | Ground |
{% hint style="info" %} I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added. {% endhint %}
CAN 1 (J2)
| Pin | Name | Dir | Lvl | Function |
|---|---|---|---|---|
| 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 | 5V | FMU CAN 1 |
| 3 | CAN1_N | I/O | 5V | FMU CAN 1 |
| 4 | GND | Ground |
{% hint style="warning" %} 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. {% endhint %}
GPIO (J3)
| Pin | Name | Dir | Lvl | Function |
|---|---|---|---|---|
| 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.
{% hint style="info" %} 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. {% endhint %}
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 |
|---|---|---|---|---|
| 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 |
{% hint style="info" %} I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added. {% endhint %}
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:
- Skynode Enterprise
- Pixhawk Payload Adapter Board
- 30-position FFC cable
- 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
{% hint style="danger" %} To avoid damage to Skynode or connected peripherals, unplug the power source before continuing to connect the PPB Adapter Board. {% endhint %}
- In order to open the locking mechanism of the FPC connector, insert a small tool into the opening at the side of the connector.\
- Carefully pull the wing of the locking mechanism towards you and out of the enclosure.\
- Repeat the previous two steps on the left side and completely unlock the connector.\
- 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.\
- 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
- On the PPB adapter board, open the locking mechanism of the FPC connector and place the board next to Skynode.\
- Slide the FFC cable into the connector, the contacts are facing down on this side.\
.JPG)
- Close the locking mechanism by pushing back the latch (see arrows on the left).\
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