Interface Specifications

This section covers the complete interface standard and the core mechanical, electrical, and external connection options of The Cube. Areas marked as LT (long term) need to be kept stable to isolate any autopilot revisions being made to the unmanned aerial vehicle (UAV).

Interface Standard

Connector Series

Low density: 0.1” over mould keyed servo connectors

Cabling: AWG24, ribbon or round, iconic color scheme

Stack: Hirose DF17, 80pos , 4 mm stacking height, 0.5 mm pitch, drop-proof

High density: JST-GH 1.25 mm

Cabling: AWG28, ribbon, iconic colour scheme

Power Module: Molex Clik-Mate 2 mm for both main and backup power (connector is not on The Cube, but on the carrier board).

The Cube

• Mechanical: 30x30 mm M1.6 mounting hole pattern, 35x35 mm footprint.

• 80 position DF17 connector: Carries all autopilot interface connections.

• No power management, which means power modules cannot be selected.

• 3.8 to 5.7V operation (absolute maximum ratings).

• 4.0 to 5.5V operation (compliant rating).

Minimal electrical protection is provided to The Cube.

The Cube I/O

Connecting Interfaces:

• Two I2C.

• Two CAN: CAN1 and CAN2.

• Four UART: TELEM1, TELEM2, GPS (I2C 1 embedded), SERIAL4(I2C 2 embedded).

• One Console: CONSOLE (SERIAL5).

• One HMI: USB extender.

Serial Ports Parameters

Port Interface and Pin Label

Main Power - | Connector: POWER1

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VDD_5V_BRICK	IN	5 V	RED/GRAY	Supply To AP from Power Brick
2	VDD_5V_BRICK	IN	5 V	RED/GRAY	Supply To AP from Power Brick
3	BATT_CURRENT_SENS	IN	3.3 V	BLACK	Battery Current Connecter
4	BATT_VOLTAGE_SENS	IN	3.3 V	BLACK	Battery Voltage Connecter
5	GND	-	GND	BLACK	GND connection
6	GND	-	GND	BLACK	GND connection

Backup Power - | Connector: POWER2

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VDD_5V_BRICK	IN	5 V	RED/GRAY	Supply To AP from Power Brick
2	VDD_5V_BRICK	IN	5 V	RED/GRAY	Supply To AP from Power Brick
3	AUX_BATT_CURRENT_SENS	IN	3.3 V	BLACK	Aux Battery Current Connecter
4	AUX_BATT_VOLTAGE_SENS	IN	3.3 V	BLACK	Aux Battery Voltage Connecter
5	GND	-	GND	BLACK	GND connection
6	GND	-	GND	BLACK	GND connection

I2C - 4 pos (one fitted as a standalone, one as an old internal) | Connector: I2C2

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VCC_5V	OUT	5 V	RED/GRAY	Supply to peripheral from AP
2	I2C_2_SCL	IN/OUT	3.3 V (PULLUPS)	BLUE/BLACK	SCL, Pull-up on AP
3	I2C_2_SDA	IN/OUT	3.3 V (PULLUPS)	GREEN/BLACK	SDA, Pull-up on AP
4	GND		GND	BLACK	GND connection

CAN (2 fitted) | Connector: CAN1, CAN2

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VCC_5V	OUT	5 V	RED/GRAY	Supply to peripheral from AP
2	CAN_H	IN/OUT	12 V	YELLOW/BLACK	CAN High
3	CAN_L	IN/OUT	12 V	GREEN/BLACK	CAN Low
4	GND	-	GND	BLACK	GND connection

UART GENERIC (autopilot side) | Connector: TELEM1, TELEM2

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VCC_5V	OUT	5 V	RED/GRAY	Supply to peripheral from AP
2	MCU_TX	OUT	3.3 V - 5.0 V TTL	YELLOW/BLACK	TX of AP
3	MCU_RX	IN	3.3 V - 5.0 V TTL	GREEN/BLACK	RX of AP
4	MCU_CTS (TX)	OUT	3.3 V - 5.0 V TTL	GRAY/BLACK	CTS (Clear To Send)
5	MCU_RTS (RX)	IN	3.3 V - 5.0 V TTL	GRAY/BLACK	RTS (Request To Send)
6	GND	-	GND	BLACK	GND connection

UART GPS (autopilot side, I2C is the original “External” bus), UART 3 | Connector: GPS1

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VCC_5V	IN	5 V	RED	Supply to GPS from AP
2	GPS_TX	IN	3.3 V - 5.0 V TTL	BLACK	TX of AP
3	GPS_RX	OUT	3.3 V - 5.0 V TTL	BLACK	RX of AP
4	SCL	IN	3.3 V	BLACK	I2C 1 SCL
5	SDA	IN/OUT	3.3 V	BLACK	I2C 1 SDA
6	BUTTON	OUT	GND	BLACK	Signal shorted to GND on press
7	IO_LED_SAFET_PROT	OUT	GND	BLACK	LED Driver For Safety Button
8	GND	-	GND	BLACK	GND connection

UART 4 (I2C2, the original “Internal” bus) | Port: GPS2

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	VCC_5V	OUT	5 V	RED/GRAY	Supply to GPS from AP
2	MCU_TX	OUT	3.3 V - 5.0 V TTL	YELLOW/BLACK	TX of AP
3	MCU_RX	IN	3.3 V - 5.0 V TTL	GREEN/BLACK	RX of AP
4	SCL	OUT	3.3 V - 5.0 V	GRAY/BLACK	I2C 2 SCL
5	SDA	IN	3.3 V - 5.0 V	GRAY/BLACK	I2C 2 SDA
6	GND	-	GND	BLACK	GND connection

UART 5 (Debug), S.Bus out - FR-SKY TELEM or Debug | Port: CONS SBUSo

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	S.Bus_Out	OUT			S.Bus Signal Output, TX of AP
2	MCU_TX	OUT	3.3 V - 5.0 V TTL		TX of AP
3	VDD_SERVO	OUT	Servo Voltage		Servo rail voltage
4	MCU_RX	IN	3.3 V - 5.0 V TTL		RX of AP
5	GND	-	GND		GND connection
6	GND	-	GND		GND connection

Debug (New Standard Debug) (Digikey PN for housing SM06B-SURS-TF(LF)(SN)-ND)

IO DEBUG

Pin Number	Name	I/O	Voltage	Wire Color	Description
1	VDD 5V PEIPH	OUT	5 V		5V
2	IO_TX	OUT	3.3 V - 5.0 V TTL		TX of AP IO_uart1 TX
3	IO_RX	IN	3.3V - 5.0 V TTL		RX of AP IO_uart1 RX
4	IO-SWDIO	I/O	3.3 V - 5.0 V TTL		Serial wire debug I/O
5	IO-SWCLK	I/O	3.3 V - 5.0 V TTL		Serial wire Clock
6	GND	OUT	GND		GND connection

FMU Debug

Pin Number	Name	I/O	Voltage	Wire Color	Description
1	VDD 5V PEIPH	OUT	5 V		5V
2	FMU_TX (SERIAL 5)	OUT	3.3 V - 5.0 V TTL		TX of AP FMU_uart5 TX
3	FMU_RX (SERIAL 5)	IN	3.3V - 5.0 V TTL		RX of AP FMU_uart5 RX
4	FMU-SWDIO	I/O	3.3 V - 5.0 V TTL		Serial wire debug I/O
5	FMU-SWCLK	I/O	3.3 V - 5.0 V TTL		Serial wire Clock
6	GND	OUT	GND		GND connection

Analog | Port:ADC

Pin Number	Name	I/)	Voltage	Wire Color	Description
1	VDD_5V_Periph	OUT
2	Pressure sense in	IN
3	GND	-			GND connection

IO USART 1/DSM/Spektrum | Port:SPKT

Pin Number	Name	I/O	Voltage	Wire Colour	Description
1	IO_USART1_RX_SPECTRUM_DSM	IN			IO USART 1 RX, DSM INPUT
2	GND	-	GND		GND
3	VDD_3V3_Spektrum	OUT	3.3 V		private Power Supply

HMI (Buzzer, USB, LEDs) | Port:USB

Pin #	Name	I/O	Voltage	Wire Colour	Description
1	V BUS	OUT	5 V	RED/GRAY	USB V BUS
2	OTG_DP1	IN/OUT	3.3 V	GREEN/BLACK	USB Data Positive (D+)
3	OTG_DM1	IN/OUT	3.3 V	RED/BLACK	USB Data Minus (D-)
4	GND	-	GND	BLACK	GND
5	BUZZER_OUT	OUT	Battery Voltage	GRAY/BLACK	VBAT (8.4 - 42 V)
6	FMU_LED_AMBER	OUT		BLACK	Boot / Error LED (FW updates)

Back Edge (can be rearranged in accordance with PCB layout) | Port：RCIN MAIN OUT AUX OUT

SERVO HEADER (0.1”, 1/1/15 power layout)

Pin Number	Name	I/O	Voltage	Wire Colour	Description
S - 1	FMU_CH1_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 2	FMU_CH2_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 3	FMU_CH3_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 4	FMU_CH4_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 5	FMU_CH5_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 6	FMU_CH6_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 7	IO_CH1_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 8	IO_CH2_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 9	IO_CH3_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 10	IO_CH4_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 11	IO_CH5_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 12	IO_CH6_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 13	IO_CH7_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 14	IO_CH8_PROT	OUT	3.3 V Servo Signal, Servo Rail Power		PWM Signal
S - 15	PPM_SBUS_PROT	IN/OUT	3.3 V / 4.5 V Powered		PPM / S.Bus Signal

The Cube 80-pin DF17 Connector (long term standard)

Pin Number	Name	I/O	Description
1	FMU_SWDIO	I/O	FMU serial wire debug I/O
2	FMU_LED_AMBER	O	Boot error LED (drive only, controlled by FET)
3	FMU_SWCLK	O	FMU serial wire debug clock
4	I2C_2_SDA	I/O	I2C Serial Data Tx/Rx
5	EXTERN_CS	O	Chip select for external SPI (NC, just for debugging)
6	I2C_2_SCL	O	I2C Serial Clock Signal
7	FMU_!RESET	I	Reset pin for the FMU
8	PROT_SPARE_1		Spare
9	VDD_SERVO_IN	I	Power for last resort I/O failsafe
10	PROT_SPARE_2		Spare
11	EXTERN_DRDY	I	Interrupt pin for external SPI (NC, just for debugging)
12	SERIAL_5_RX	I	UART 5 RX (Receive Data)
13	GND		System GND
14	SERIAL_5_TX	O	UART 5 TX (Transmit Data)
15	GND		System GND
16	SERIAL_4_RX	I	UART 4 RX (Receive Data)
17	SAFETY		Safety button input
18	SERIAL_4_TX	O	UART 4 TX (Transmit Data)
19	VDD_3V3_SPEKTRUM_EN	O	Enable for the Spektrum voltage regulator
20	SERIAL_3_RX	I	UART 3 RX (Receive Data)
21	PRESSURE_SENS_IN	AI	Analogue Signal port, for pressure sensor, Laser range finder, or Sonar
22	SERIAL_3_TX	O	UART 3 TX (Transmit Data)
23	AUX_BATT_VOLTAGE_SENS	AI	Voltage sense for Aux battery input
24	ALARM	O	Buzzer PWM Signal
25	AUX_BATT_CURRENT_SENS	AI	Current sense for Aux battery input
26	IO_VDD_3V3	I	IO chip power, pinned through for debug
27	VDD_5V_PERIPH_EN	O	Enable voltage supply for Peripherals
28	IO_LED_SAFET_PROT	O	IO-LED_SAFETY (safety LED) pinned out for IRIS
29	VBUS	I	USB VBus (VDD)
30	SERIAL_2_RTS		UART 2 RTS (Request To Send)
31	OTG_DP1	I/O	USB Data+ (D)
32	SERIAL_2_CTS		UART 2 CTS (Clear To Send)
33	OTG_DM1	I/O	USB Data- (M)
34	SERIAL_2_RX	I	UART 2 RX (Receive Data)
35	I2C_1_SDA	I/O	I2C Serial Data Tx/Rx
36	SERIAL_2_TX	O	UART 2 TX (Transmit Data)
37	I2C_1_SCL	O	I2C Serial Clock Signal
38	SERIAL_1_RX	I	UART 1 RX (Receive Data)
39	CAN_L_2	I/O	FMU CAN bus Low Signal Driver
40	SERIAL_1_TX	O	UART 1 TX (Transmit Data)
41	CAN_H_2	I/O	FMU CAN bus High Signal Driver
42	SERIAL_1_RTS		UART 1 RTS (Request To Send)
43	VDD_5V_PERIPH_OC	I	Error state message from Peripheral power supply
44	SERIAL_1_CTS		UART 1 CTS (Clear To Send)
45	VDD_5V_HIPOWER_OC	I	Error state message from High power Peripheral power supply
46	IO_USART_1_TX	O	I/O USART 1 TX
47	BATT_VOLTAGE_SENS_PROT	AI	Voltage sense from main battery
48	IO_USART1_RX_SPECTRUM_DSM	O	Signal from Spectrum receiver
49	BATT_CURRENT_SENS_PROT	AI	Current sense from main battery
50	FMU_CH1_PROT	O	FMU PWM output channel 1
51	SPI_EXT_MOSI	O	External SPI, for debug only
52	FMU_CH2_PROT	O	FMU PWM output channel 2
53	VDD_SERVO	I	VDD_Servo, for monitoring servo bus
54	FMU_CH3_PROT	O	FMU PWM Output Channel 3
55	VDD_BRICK_VALID	I	Main Power valid signal
56	FMU_CH4_PROT	O	FMU PWM Output Channel 4
57	VDD_BACKUP_VALID	I	Backup Power valid Signal
58	FMU_CH5_PROT	O	FMU PWM Output Channel 5
59	VBUS_VALID	I	USB bus valid signal
60	FMU_CH6_PROT	O	FMU PWM Output Channel 6
61	VDD_5V_IN_PROT	I	Main power (5V) into FMU from power selection
62	PPM_SBUS_PROT	I	PPM / S.Bus Signal Input
63	VDD_5V_IN_PROT	I	Main power (5V) into FMU from power selection
64	S.BUS_OUT	O	S.Bus Signal Output
65	IO_VDD_5V5	O	IO VDD 5.5 V
66	IO_CH8_PROT	O	I/O PWM Output Channel 8
67	SPI_EXT_MISO	I	External SPI, for Debug only
68	IO_CH7_PROT	O	I/O PWM Channel 7
69	IO_SWDIO	I/O	I/O serial wire debug
70	IO_CH6_PROT	O	I/O PWM Output Channel 6
71	IO_SWCLK	O	I/O Serial Wire Debug Clock
72	IO_CH5_PROT	O	I/O PWM Output Channel 5
73	SPI_EXT_SCK	O	External SPI, for Debug only
74	IO_CH4_PROT	O	I/O PWM Output Channel 4
75	IO_!RESET	I	I/O Reset Pin
76	IO_CH3_PROT	O	I/O PWM Output Channel 3
77	CAN_L_1	I/O	FMU CAN bus Low Signal Driver
78	IO_CH2_PROT	O	I/O PWM Output Channel 2
79	CAN_H_1	I/O	FMU CAN bus High Signal Driver
80	IO_CH1_PROT	O	I/O PWM Output Channel 1

Differences between the Colored Cubes

The Cube	Cube Orange+	Cube Orange	Cube Blue H7	Cube Purple H7	Cube Yellow	Cube Black+	Cube Black	Cube Green	Cube Blue	Cube Purple F4
Processor	STM32H757	STM32H753	STM32H753	STM32H753	STM32F777	STM32F427 V3	STM32F427 V3	STM32F427 V3	STM32F427 V3	STM32F427 V3
Remote Signal	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM	PPM/SBUS/DSM
I/O PWN Voltage	3.3V/5V software selectable	3.3V/5V software selectable	3.3V/5V software selectable	3.3V/5V software selectable	3.3V/5V software selectable	3.3V	3.3V	5.4v	3.3V	3.3V
Redundancy	Triple Redundancy	Triple Redundancy	Triple Redundancy	N/A	Triple Redundancy	Triple Redundancy	Triple Redundancy	Triple Redundancy	Triple Redundancy	N/A
Isolation System	Y	Y	Y	N	Y	Y	Y	Y	Y	N
Temp Regulator	Y	Y	Y	N	Y	Y	Y	Y	Y	N
Number of Accelerometers	Three	Three	3	1	3	3	3	3	3	1
Number of Gyroscopes	Three	Three	3	1	3	3	3	3	3	1
Number of Magnetometers	One	One	1	N/A	1	2	3	3	3	1
Number of Barometers	Two	Two	2	1	2	2	2	2	2	1
Manufacturing Origin	Taiwan	Taiwan	U.S.A	Taiwan	Taiwan	Taiwan	Taiwan	Taiwan	U.S.A	Taiwan
Product Lifecycle	Available	Available	Available	Available	Available	EOL Use Cube Orange	EOL Use Cube Orange	EOL Use Cube Orange	EOL Use Cube Blue H7	EOL Use Cube Purple H7