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Pixhawk Adapter Board

The Pixhawk adapter board is used to break out the Skynode flight control interfaces on J3 and J4 to connectors and pinouts compatible to the Pixhawk-standard.
The voltage levels for all signals brought out from the FMU to the Pixhawk Adapter Board are either 5V or 3.3V compliant. Refer to the table below to check the voltage levels of specific pins. Exceeding these voltages will permanently damage the Flight Management Unit inside Skynode.

Connector Locations

Pixhawk Adapter Board.stl
1MB
Binary
3D model mockup

Schematic

Pixhawk-Adapter-Board_RC05.pdf
169KB
PDF
Pixhawk Adapter RC05
Pixhawk-Adapter-Board_RC06.pdf
181KB
PDF
Pixhawk Adapter RC06
Check these release notes for details about the changes.

Connectors

ID
Name
Connector
Description
J11
Primary
Molex Pico-Clasp 5015714007
Connect to Skynode Primary (J4)
J12
Telem 1
JST GH 6-pin
SM06B-GHS-TB
J13
GPS 1
JST GH 10-pin
SM10B-GHS-TB
(until rev 5 included) JST GH 11-pin
SM11B-GHS-TB (from rev 6 included)
Primary GPS with external compass, safety switch and led
J14
CAN 1
JST GH 4-pin
SM04B-GHS-TB
J15
FMU
Pin Header
TSW-108-08-G-T-RA
PWM channels from FMU, input capable
J16
SBUS RC
JST GH 3-pin
SM03B-GHS-TB
SBUS protocol RC input
J18
I2C 1
JST GH 4-pin
SM04B-GHS-TB
ID
Name
Connector
Description
J21
Secondary
Molex Pico-Claspre team is looki 5015714007
Connect to Skynode Secondary (J3)
J22
SBUS OUT
JST GH 3-pin
SM03B-GHS-TB
SBUS output
J23
GPS 2
JST GH 6-pin
SM06B-GHS-TB
Redundant GPS
J24
SPI
JST GH 11-pin
SM11B-GHS-TB
J25
IO
Pin Header
TSW-108-08-G-T-RA
PWM channels from IO
J26
Telem 3
JST GH 6-pin
SM06B-GHS-TB
J27
CAN 2
JST GH 4-pin
SM04B-GHS-TB
J28
I2C 2
JST GH 4-pin
SM04B-GHS-TB

Pinouts

Telem 1 (J12)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_HIPOWER
5V
5V supply for peripherals, max. 1.0A (fused)
2
UART7_TX
OUT
3.3V
Telem 1 TX
3
UART7_RX
IN
3.3V
Telem 1 RX
4
UART7_CTS
IN
3.3V
Telem 1 CTS
5
UART7_RTS
OUT
3.3V
Telem 1 RTS
6
GND
Ground

GPS 1(J13)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_CAN1_GPS1
5V
5V supply for primary GPS and CAN interface
2
USART1_TX
OUT
3.3V
GPS 1 TX
3
USART1_RX
IN
3.3V
GPS 1 RX
4
I2C1_SCL
I/O
3.3V
I2C SCL for external magnetometer
5
I2C1_SDA
I/O
3.3V
I2C SDA for external magnetometer
6
GPS_PPS
IN
3.3V
PPS signal from GPS module
7
FMU_IO_SAFETY_SWITCH_IN
IN
3.3V
Safety switch state input
8
FMU_IO_nSAFETY_SWITCH_LED_OUT
OUT
3.3V
Safety switch led output
9
FMU_VDD_3V3
OUT
3.3V
3.3V supply for peripherals, max 50mA
10
BUZZER_1_INV
OUT
Buzzer output (open drain)
11
GND
Ground
I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.
The highlighted pin 6 was added in rev 6 of the Pixhawk Adapter Board, to ensure compatibility with the PX4 F9P GPS module. For backwards compatibility with the Freefly RTK GPS module, a custom cable needs to be made.

CAN 1 (J14)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_CAN1_GPS1
5V
5V supply for primary GPS and CAN interface
2
CAN1_P
I/O
5V
FMU CAN 1
3
CAN1_N
I/O
5V
FMU CAN 1
6
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 Pixhawk Adapter Boards (until rev 5 included). This configuration assumed that Skynode was at the end of the bus. Rev 11 and onwards has the 120Ω bus termination resistor on the Pixhawk Adapter Boards (from rev 6 included), without built-in termination inside of Skynode. When designing a wire harness instead of using the Pixhawk Adapter Boards, usage of 120Ω termination resistors at both ends of the bus is mandatory, following ISO 11898..

FMU - ESC and Servo (J15)

Pin
Name
Dir
Lvl
PWM/
OneShot
DShot
Shared with PPB
1
FMU_CH1
I/O
3.3V
Yes
Yes
2
FMU_CH2
I/O
3.3V
Yes
Yes
3
FMU_CH3
I/O
3.3V
Yes
Yes
4
FMU_CH4
I/O
3.3V
Yes
Yes
5
FMU_CH5
I/O
3.3V
Yes
Yes
6
FMU_CH6
I/O
3.3V
Yes
Yes
7
FMU_CH7
I/O
3.3V
Yes
Yes
8
FMU_CH8
I/O
3.3V
Yes
Yes

SBUS RC (J16)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_SBUS_RC
5V
5V supply for RC receiver, max 250mA
2
IO_SBUS_INPUT
IN
3.3V
SBUS protocol RC input
3
GND
Ground

I2C 1 (J18)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_CAN1_GPS1
5V
5V supply for primary GPS and CAN interface
2
I2C1_SCL
I/O
3.3V
I2C SCL for external peripherals
3
I2C1_SDA
I/O
3.3V
I2C SDA for external peripherals
6
GND
Ground
I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.

SBUS OUT (J22)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_SBUS_RC
Not connected
2
IO_SBUS_OUTPUT
OUT
3.3V
SBUS protocol output
3
GND
Ground

GPS 2 (J23)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_PERIPH
5V
5V supply for peripherals
2
USART8_TX
OUT
3.3V
GPS 2 TX
3
USART8_RX
IN
3.3V
GPS 2 RX
4
I2C2_SCL
I/O
3.3V
I2C SCL for external magnetometer
5
I2C2_SDA
I/O
3.3V
I2C SDA for external magnetometer
6
GND
Ground
I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.

SPI (J24)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_PERIPH
2
SPI6_SCK
OUT
3.3V
SPI Clock
3
SPI6_MISO
IN
3.3V
SPI MISO
4
SPI6_MOSI
OUT
3.3V
SPI MOSI
5
SPI6_nCS1
OUT
3.3V
Chip select 1
6
NC
7
SPI6_nSYNC
OUT
3.3V
Sync signal
8
SPI6_DRDY1
IN
3.3V
Data ready 1
9
NC
10
SPI6_nRESET
OUT
3.3V
Reset
11
GND

IO - ESC and Servo (J25)

Pin
Name
Dir
Lvl
PWM/
OneShot
DShot
Shared with
PPB
1
IO_CH1
OUT
3.3V
Yes
2
IO_CH2
OUT
3.3V
Yes
3
IO_CH3
OUT
3.3V
Yes
4
IO_CH4
OUT
3.3V
Yes
5
IO_CH5
OUT
3.3V
Yes
6
IO_CH6
OUT
3.3V
Yes
7
IO_CH7
OUT
3.3V
Yes
8
IO_CH8
OUT
3.3V
Yes

Telem 3 (J26)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_PERIPH
5V
5V supply for peripherals
2
USART2_TX
OUT
3.3V
Telem 3 TX
3
USART2_RX
IN
3.3V
Telem 3 RX
4
NC
5
NC
6
GND
Ground

CAN 2 (J27)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_PERIPH
5V
5V supply for peripherals
2
CAN2_P
I/O
5V
FMU CAN 2
3
CAN2_N
I/O
5V
FMU CAN 2
6
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 Pixhawk Adapter Boards (until rev 5 included). This configuration assumed that Skynode was at the end of the bus. Rev 11 and onwards has the 120Ω bus termination resistor on the Pixhawk Adapter Boards (from rev 6 included), without built-in termination inside of Skynode. When designing a wire harness instead of using the Pixhawk Adapter Boards, usage of 120Ω termination resistors at both ends of the bus is mandatory, following ISO 11898.

I2C 2 (J28)

Pin
Name
Dir
Lvl
Function
1
VDD_5V_PERIPH
5V
5V supply for peripherals
2
I2C2_SCL
I/O
3.3V
I2C SCL for external peripherals
3
I2C2_SDA
I/O
3.3V
I2C SDA for external peripherals
6
GND
Ground
I2C lines are pulled up with 1kΩ in Skynode. External pull up resistors shall not be added.