Cube Red

Overview

The Cube Red is a professional dual FMU flight control system that ensures operational reliability through its two dual-core, double-precision FPU processors. The newly added Ethernet interface and DSI out provide an unprecedented flight experience. An Isolated Static Air port minimizes disruptions from external airflow, ensuring stable static pressure. Also with Ardupilot firmware, you can utilize this unit with any type of UXV.

Feature

1. Powerful processing performance is provided by two STM32H7 dual-core processors, each equipped with double-precision FPU (Floating Point Unit) operations.

2. Cube Red is equipped with 4 sets of IMUs and 3 barometers for redundancy, ensuring continuous safe operation during flight.

3. Replaceable fully closed uppercase and isolated static air ducts provide stable pressure to barometers for accurate altitude measurement.

4. Provides foams with different hardness options, catering to various flight purposes.

5. The CAN FD port offers real-time high transmission rates.

6. The Type-C Debugging interface has been updated to the future-proof USB Type-C standard.

Operating Conditions and Performance

About	Description
POWER input voltage / rated input current	4.1 - 5.7 V / 2.5 A; 0 - 20 V is safe for the system but it will not work
POWER rated output / input power	14 W
USB port input voltage / rated input current	4 - 5.7 V / 250 mA
Servo rail input voltage	4 - 10.5 V
Waterproof performance	Not waterproof. External waterproof protection is needed
Operation Temperature	-10° / 55°

Ports Standard and Definition

Standard Carrier Board Ports Standard

Connector	Connector Type
GPS1	JST-GH 1.25 mm (8-pin)
GPS2	JST-GH 1.25 mm (6-pin)
TELEM1	JST-GH 1.25 mm (6-pin)
TELEM2	JST-GH 1.25 mm (6-pin)
I2C2	JST-GH 1.25 mm (4-pin)
USB	JST-GH 1.25 mm (6-pin)
CAN1	JST-GH 1.25 mm (4-pin)
CAN2	JST-GH 1.25 mm (4-pin)
CAN3	JST-GH 1.25 mm (4-pin)
POWER1	Molex CLIK-Mate 2mm (6-pin)
POWER2	Molex CLIK-Mate 2mm (6-pin)
ADC	JST-GH 1.25 mm (3-pin)
DSI	JST-GH 1.25 mm (15-pin)
ETH	TE Multi-purp pluh(8P)

Cube Red 80-Pin DF17 Connector

Connector 1 Assignments

Pin#	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	CAN_L_3	I/O	CAN bus Low Signal Driver
9	VDD_SERVO_IN	I	Power for last resort I/O failsafe
10	CAN_H_3	I/O	CAN bus High Signal Driver
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

Connector 2 Assignments

Pin#	Name	I/O	Description
1	GND		System GND
2	FMU_BOOT	I	FMU Boot
3	FC_NET_TX+	I/O	Ethernet TX+,Auto-MDIX support
4	NC		Use for future
5	GND
6	IO_BOOT		IO MCU BOOT
7	FC_NET_TX-	I/O	Ethernet TX-,Auto-MDIX support
8	NC		Use for future
9	GND		System GND
10	NC		Use for future
11	FC_NET_RX+	I/O	Ethernet RX+,Auto-MDIX support
12	NC		Use for future
13	GND		System GND
14	NC		Use for future
15	FC_NET_RX-	I/O	Ethernet RX-,Auto-MDIX support
16	NC		Use for future
17	GND		System GND
18	NC		Use for future
19	FC_NET_LEDY	O	Link Speed LED Indication
20	NC		Use for future
21	FC_NET_LEDG	O	Ethernet Link activity LED Indication
22	NC		Use for future
23	FC_NET_VCC	I	Ethernet 3.3V Power in
24	NC		Use for future
25	Timestamp rtc	I	Timestamp RTC
26	NC		Use for future
27	GND		System GND
28	NC		Use for future
29	CAN_L_1	I/O	CAN bus Low Signal Driver
30	NC		Use for future
31	CAN_H_1	I/O	CAN bus High Signal Driver
32	NC		Use for future
33	CAN_L_2	I/O	CAN bus Low Signal Driver
34	NC		Use for future
35	CAN_H_2	I/O	CAN bus High Signal Driver
36	NC		Use for future
37	CAN_L_3	I/O	CAN bus Low Signal Driver
38	NC		Use for future
39	CAN_H_3	I/O	CAN bus High Signal Driver
40	NC		Use for future
41	GND		System GND
42	NC		Use for future
43	UART8_RX	I	IO UART 8 RX (Receive Data)
44	NC		Use for future
45	UART8_TX	O	IO UART 8 TX (Transmit Data)
46	NC		Use for future
47	GND		System GND
48	NC		Use for future
49	DSI_CKP	O	MIPI DSI Host Clock Postive
50	NC		Use for future
51	DSI_CKN	O	MIPI DSI Host Clock Negative
52	NC		Use for future
53	GND		System GND
54	NC		Use for future
55	DSI_D0P	O	MIPI DSI Host DATA0 Postive
56	NC		Use for future
57	DSI_D0N	O	MIPI DSI Host DATA0 Negative
58	NC		Use for future
59	GND		System GND
60	NC		Use for future
61	DSI_D1P	O	MIPI DSI Host DATA1 Postive
62	NC		Use for future
63	DSI_D1N	O	MIPI DSI Host DATA1 Negative
64	NC		Use for future
65	GND		System GND
66	NC		Use for future
67	FMU_DAC	O	FMU Analogue output
68	NC		Use for future
69	IO_DAC	O	IO Analogue output
70	NC		Use for future
71	GND		System GND
72	NC		Use for future
73	VDD_5V_IN_backup	I	Main power (5V) into FMU from power selection
74	NC		Use for future
75	VDD_5V_IN_backup	I	Main power (5V) into FMU from power selection
76	NC		Use for future
77	VDD_5V_IN_backup	I	Main power (5V) into FMU from power selection
78	NC		Use for future
79	VDD_5V_IN_backup	I	Main power (5V) into FMU from power selection
80	NC		Use for future

Ports and Protocols

Name	Function	Marking
SERIAL 1 / UART 1	UART 1 with hardware flow control. 3.3V-5V CMOS TTL level, with ESD protection	TELEM1
SERIAL 2 / UART 2	UART 2 with hardware flow control. 3.3V-5V CMOS TTL level, with ESD protection	TELEM2
SERIAL 3 / UART 3 / I2C 1	3.3V-5V CMOS TTL level, with ESD protection	GPS1
SERIAL 4 / UART 4 / I2C 2	UART 4 / I2C 2, 3.3V-5V CMOS TTL level, with ESD protection	GPS2
SERIAL 5 / UART 5 (Debug Console)	UART 5，Debug Console	CONS
I2C 2	Independent I2C 2 port. Drivers are on-board on FMU. UN-buffered, and pulled up to 3.3V COMS TTL level	I2C2
CAN Bus	Standard CAN Bus. Drivers are on-board on FMU.	CAN1 CAN2 CAN3
R/C IN	Support CPPM / Futaba S.Bus signal input	RCIN
DSM / USART	Support Spektrum DSM® Technology, Spektrum DSM2™ / DSMX™ compatible input; I/O USART 1 RX	SKPT
S.Bus OUT / RSSI IN	S.Bus Servo I/O. PPM Output. Can be used as RSSI input	SBUSo
POWER	Main Power source and Backup Power source Input	POWER1 POWER2
MAIN OUT	Standard PWM Servo Signal I/O Port x 8	MAIN OUT
AUX OUT	Programmable FMU GPIO x 6. Support PWM Signal Output	AUX OUT
USB	Human Machine Interface (HMI): LED, Speaker and USB extension	USB
ADC	3.3 V ADC Input	ADC
SPI	Built-in SPI port, with NO buffer, can only use short cable for connection. Not recommended.	Built-in contact point
Debug	I/O and FMU Testing Port	Built-in port
ETH	Ethernet Port
DSI	MIPI DSI output and Timestamp,FMU/IO BOOT

The Cube Series Interface Specification

Scope of this Document

This document covers the complete interface standard and core mechanical, electrical and external connection options of The Cube module series. Sections marked as LT (long term) are intended to be kept stable to isolate vehicle from autopilot revisions.

Interface Standard

Connector Series

Low density: 0.1” over mould Futaba keyed servo connectors (Mfg. to be identified)

-Cabling: AWG24, ribbon or round, iconic colour 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

The Cube

Mechanical: 30x30 mm M3 mounting hole pattern, 35x35 mm footprint

80 position DF17 connector. Carries all autopilot interface connections.

Minimal (read: really minimal) electrical protection

No power management（intergrade in Carrier board）

3.8 to 5.7V operation (absolute maximum ratings)

4.0 to 5.5V operation (compliant rating)

The Cube IO

Total connectivity:

• I2C * 2

• CAN * 3

• Serial * 5 : TELEM1, TELEM2, GPS (I2C 1 embedded), SERIAL4(I2C 2 embedded),

Serial 5 is used for the on-board ADSB-IN receiver that is featured on newer carrier boards

• HMI * 1

Carrier Board Port Interface and Pin Label

SERIAL 1 / UART 1 | Port: TELEM1

Pin #	Name	I/O	Voltage	Wire Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC
2	SERIAL_1_TX	OUT	3.3 V - 5.0 V TTL	Orange+/BLACK	UART 1 TX (Transmit Data)
3	SERIAL_1_RX	IN	3.3 V - 5.0 V TTL	GREEN/BLACK	UART 1 RX (Receive Data)
4	SERIAL_1_CTS (TX)	OUT	3.3 V - 5.0 V TTL	GRAY/BLACK	UART 1 CTS (Clear To Send)
5	SERIAL_1_RTS (RX)	IN	3.3 V - 5.0 V TTL	GRAY/BLACK	UART 1 RTS (Request To Send)
6	GND		GND	BLACK	GND

SERIAL 3 / UART 3 (GPS) / I2C 1 | Port: GPS1

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	IN	5 V	RED	VCC Power Supply To GPS From AP
3	SERIAL_3_TX	OUT	3.3 V - 5.0 V TTL	BLACK	UART 3 TX (Transmit Data)
2	SERIAL_3_RX	IN	3.3 V - 5.0 V TTL	BLACK	UART 3 RX (Receive Data)
4	I2C_1_SCL	IN	3.3 V	BLACK	I2C 1 Clock Signal
5	I2C_1_SDA	IN/OUT	3.3 V	BLACK	I2C 1 Serial Data
6	BUTTON		GND	BLACK	Signal shorted to GND on press
7	IO_LED_SAFET_PROT		GND	BLACK	LED Driver For Safety Button
8	GND		GND	BLACK	GND

HMI (Buzzer / USB / LED) | Port: USB

Pin #	Name	I/O	Voltage	Cable Colour	Definition
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)

I2C 2 | Port: I2C 2

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC Power Supply
2	I2C_2_SCL	IN/OUT	3.3 V (PULLUPS)	BLUE/BLACK	I2C 2 Clock Signal, Pull-up on AP
3	I2C_2_SDA	IN/OUT	3.3 V (PULLUPS)	GREEN/BLACK	I2C 2 Serial Data, Pull-up on AP
4	GND		GND	BLACK	GND

CAN 1 | Port: CAN1

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC Power Supply
2	CAN_H_1	IN/OUT	12 V	Orange+/BLACK	CAN High
3	CAN_L_1	IN/OUT	12 V	GREEN/BLACK	CAN Low
4	GND		GND	BLACK	GND

CAN 2 | Port: CAN2

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC Power Supply
2	CAN_H_2	IN/OUT	12 V	Orange+/BLACK	CAN High
3	CAN_L_2	IN/OUT	12 V	GREEN/BLACK	CAN Low
4	GND		GND	BLACK	GND

ADC | Port: ADC

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VDD_5V_PRES	OUT	5 V	RED	Power Supply
2	PRESSURE_SENS_IN	IN		BLACK
3	GND		GND	BLACK	GND

IO USART 1 / DSM | Port: SPKT

Pin #	Name	I/O	Voltage	Cable Colour	Definition
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		Independent Power Supply

SERIAL 5 / UART 5 (Debug Console) / S.Bus OUT | Port: CONS SBUSo

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1 SBUSo	S.Bus_Out	OUT			S.Bus Signal Output
2 CONS	SERIAL_5_TX	OUT	3.3 V - 5.0 V TTL		UART 5 TX (Transmit Data)
3 SBUSo	VDD_SERVO	OUT	Servo Voltage
4 CONS	SERIAL_5_RX	IN	3.3 V - 5.0 V TTL		UART 5 RX (Receive Data)
5 SBUSo	GND		GND		GND
6 CONS	GND		GND		GND

Main Power POWER 1 | Port: POWER1

Pin #	Name	I/O	Voltage	Cable Colour	Definition
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_PROT		3.3 V	BLACK	Battery Current Connecter
4	BATT_CURRENT_VOLTAGE_PROT	IN	3.3 V	BLACK	Battery Voltage Connecter
5	GND		GND	BLACK	GND
6	GND		GND	BLACK	GND

Backup Power POWER 2 | Port: POWER2

Pin #	Name	I/O	Voltage	Cable Colour	Definition
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		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

CPPM / S.BUS / SERVO SYSTEM | Port: RCIN MAIN OUT AUX OUT

Pin #	Name	I/O	Voltage	Definition
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

SERIAL 2 / UART 2 | Port: TELEM2

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC
2	SERIAL_2_TX	OUT	3.3 V - 5.0 V TTL	Orange+/BLACK	UART 2 TX (Transmit Data)
3	SERIAL_2_RX	IN	3.3 V - 5.0 V TTL	GREEN/BLACK	UART 2 RX (Receive Data)
4	SERIAL_2_CTS (TX)	OUT	3.3 V - 5.0 V TTL	GRAY/BLACK	UART 2 CTS (Clear To Send)
5	SERIAL_2_RTS (RX)	IN	3.3 V - 5.0 V TTL	GRAY/BLACK	UART 2 RTS (Request To Send)
6	GND		GND	BLACK	GND

SERIAL 4 / UART 4 / I2C 2 | Port: GPS2

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC Power Supply To GPS From AP
2	SERIAL_4_TX	OUT	3.3 V - 5.0 V TTL	Orange+/BLACK	UART 4 TX (Transmit Data)
3	SERIAL_4_RX	IN	3.3 V - 5.0 V TTL	GREEN/BLACK	UART 4 RX (Receive Data)
4	I2C_2_SCL	OUT	3.3 V - 5.0 V	GRAY/BLACK	I2C 2 Clock Signal
5	I2C_2_SDA	IN	3.3 V - 5.0 V	GRAY/BLACK	I2C 2 Serial Data
6	GND		GND	BLACK	GND

CAN 3 | Port: CAN3

Pin #	Name	I/O	Voltage	Cable Colour	Definition
1	VCC_5V	OUT	5 V	RED/GRAY	VCC Power Supply
2	CAN_H_2	IN/OUT	12 V	Orange+/BLACK	CAN High
3	CAN_L_2	IN/OUT	12 V	GREEN/BLACK	CAN Low
4	GND		GND	BLACK	GND

Ethernet: ETH1

Pin #	Name	I/O	Description
1	TXP/RXP	IN/OUT	Ethernet TXP/RXP Auto-MDIX support
2	TXN/RXN	IN/OUT	Ethernet TXN/RXN Auto-MDIX support
3	RXP/TXP	IN/OUT	Ethernet RXP/TXP Auto-MDIX support
4	NC		No connect
5	NC		No connect
6	RXN/TXN	IN/OUT	Ethernet RXN/TXN Auto-MDIX support
7	NC		No connect
8	NC		No connect

DSI / Timestamp / Boot| Port: DSI

Pin #	Name	I/O	Definition
1	IO_BOOT_0	OUT	IO BOOT
2	FMU_BOOT_0	OUT	FMU BOOT
3	TIMESTAMP_RTC	OUT	TIMESTAMP
4	GND		GND
5	DSI_CKP	OUT	MIPI DSI Host Clock Postive
6	DSI_CKN	OUT	MIPI DSI Host Clock Negative
7	GND		GND
8	DSI_D0P	OUT	MIPI DSI Host DATA 0 Postive
9	DSI_D0N	OUT	MIPI DSI Host DATA 0 Negative
10	GND		GND
11	DSI_D1P	OUT	MIPI DSI Host DATA 1 Postive
12	DSI_D1N	OUT	MIPI DSI Host DATA 1 Negative
13	GND		GND
14	IO_DAC	OUT	IO Analog output
15	FMU_DAC	OUT	FMU Analog output

System architecture

The Cube continues with the FMU + IO architecture from the previous generation, incorporating the two functional blocks in a single physical module.

PWM Outputs

The Cube has eight PWM outputs that are connected to IO and can be controlled by IO directly via R/C input and on-board mixing even if FMU is not active (failsafe / manual mode). Multiple update rates can be supported on these outputs in three groups; one group of four and two groups of two. PWM signal rates up to 400Hz can be supported. These 8 PWM's are output ONLY and are capable of driving up to 50mA each, but only a total of 100mA for the 8.

Six PWM outputs are connected to FMU and feature reduced update latency. These outputs cannot be controlled by IO in failsafe conditions. Multiple update rates can be supported on these outputs in two groups; one group of four and one group of two.

PWM signal rates up to 400Hz can be supported.

All PWM outputs are EDS-protected, and they are designed to survive accidental miss-connection of servos without being damaged. The servo drivers are specified to drive a 50pF servo input load over 2m of 26AWG servo cable.

the I/O PWM outputs can also be configured as individual GPIOs. Note that these are not high-power outputs – the PWM drivers are designed for driving servos and similar logic inputs only, not relays or LEDs.

Peripheral Ports

All peripherals are connected through two 80 pin connectors, and the peripherals are connected via a baseboard that can be customized for each application

Base Board

The initial base board features separate connectors for each of the peripheral ports (with a few exceptions.

Five serial ports are provided. Serial 1 and 2 feature full flow control. Serial 3 is recommended as the GPS port and has the safety button and (possibly the safety led) as well as I2C for the compass and RGB LED. Serial 4 also has I2C, but on the second bus, thus allowing two compass modules to be connected at the same time. Serial 5 is available as a header underneath the board. Serial ports are 3.3V CMOS logic level, 5V tolerant, buffered and ESD-protected.

The SPI port is not buffered; it should only be used with short cable runs. Signals are 3.3V CMOS logic level, but 5V tolerant. SPI is only available to test points on the first base board, along with a CS and INT pin.

Analogue 1-3 are protected against inputs up to 12V, but scaled for 0-3.3V inputs. The RSSI input supports either PWM or analogue RSSI. This input shares a pin with S.Bus output - only one may be connected at a time.

CPPM, S.Bus and DSM/Spektrum input are unchanged from previous versions.

The CAN ports are standard CAN-Bus; termination for one end of the bus is fixed on- board. Drivers are on-board the FMU

The piezo port will drive most piezo elements in the 5 - 300nF range at up to 35V. it is intended to be extremely loud, with the achievable sound pressure level limited by the sensitivity of the piezo element being driven.

I2C is direct driven, un-buffered, and pulled up to *3.3v on-board* the FMU

Serial 5 is used for the on-board ADSB-IN receiver that is featured on newer carrier boards

Power Architecture

Power management module (separate from the FMU)

Key features of The Cube power architecture:

• Single, independent 5V supply for the flight controller and peripherals.

• Integration with *2 power bricks* or compatible alternative, including current and voltage sensing.

• Low power consumption and heat dissipation.

• Power distribution and monitoring for peripheral devices.

• Protection against common wiring faults; under/over-voltage protection, overcurrent protection, thermal protection.

• Brown-out resilience and detection.

FMU and IO Power Supplies

Both FMU and IO operate at 3.3V, and each has its own private dual-channel regulator. As in The Cube , each regulator features a power-on reset output tied to the regulator’s internal power-up and drop-out sequencing.

Power Sources

Power may be supplied to The Cube via USB, via the power brick port, or the second brick port. Each power source is protected against reverse-polarity connections and back-powering from other sources.

Power Brick Port

The brick port is the preferred power source for Cube, and brick power will always be selected if it is available.

Servo Power

The Cube supports both standard (5V) and high-voltage (up to 10V) servo power with some restrictions.

IO will accept power from the servo connector up to 10V. This allows IO to failover to servo power in all cases if the main power supply is lost or interrupted.

FMU and peripherals will NOT accept power from the servo connector.

Aux Power

The Cube introduces a backup power port; this is set up the same as the primary power input.

At input voltages over 5.7V power is locked out.

The Cube and peripherals combined may draw up to 2.75A total when operating on Aux power, provided that the Brick or other power source can supply the required current.

Power is never supplied by The Cube to servos.

Servo rail

The I/O chip takes power up to 10.5v from the servo rail; this is used to revert to manual mode in the unfortunate event that the other two main sources of power fail. This is only useful for plane, and only useful if the I/O chip has been mapped correctly.

USB-Type C Power

Power from USB-Type C is supported for software update, testing and development purposes. USB-Type C power is supplied to the peripheral ports for testing purposes, however total current consumption must typically be limited to 3A, including peripherals, to avoid overloading the host USB port.

Multiple Power Sources

When more than one power source is connected, power will be drawn from the highest-priority source with a valid input voltage.

In most cases, FMU should be powered via the power brick or a compatible off board regulator via the brick port or auxiliary power rail.

In desktop testing scenarios, taking power from USB avoids the need for a BEC or similar servo power source (though servos themselves will still need external power).

Summary

For each of the components listed, the input voltage ranges over which the device can be powered from each input is shown.

	Brick port	Aux port	USB port	Servo rail
FMU	4—5.7V	4—5.7V	4—5.7V	NIL
IO	4—5.7V	4—5.7V	4—5.7V	4 - 10.5V
Peripherals	4—5.7V	4—5.7V 2.5A max	4—5.7V 2.5A max	NIL

The Cube provides power routing, over/under voltage detection and protection, filtering, switching, current-limiting and transient suppression for peripherals. Power outputs to peripherals feature ESD and EMI filtering, and the power supply protection scheme ensures that no more than 5.5V is presented to peripheral devices.

Power is disconnected from the peripherals when the available supply voltage falls below 3.8V, or rises above approximately 5.7V.

Peripheral power is split into two groups:

Serial 1 (TELEM 1) has a private 1.5A current limit, intended for powering a low power. This output is separately EMI filtered and draws directly from the USB / Brick inputs. Peak power draw on this port should not exceed 1.5A, never power your telemetry from this port under any circumstance.

All other peripherals share a 1A current limit and a single power switch. Peak power draw on this port should not exceed 1.5A. Each group is individually switched under software control.

The Spektrum / DSM R/C interface draws power from its own regulator, rather than from either of the groups above. This port is switched under software control so that Spektrum / DSM binding can be implemented. Spektrum receivers generally draw ~25mA.

S.Bus and CPPM receivers are powered by a dedicated power supply. Please do not connect any servos to this power, only an RX by itself.

Capacitor Backup

Both the FMU and IO microcontrollers feature Capacitor-backed real-time clocks and SRAM. The on-board backup Capacitor has capacity sufficient for the intended use of the clock and SRAM, which is to provide storage to permit orderly recovery from unintended power loss or other causes of in-air restarts. The capacitors are recharged from the FMU 3.3V rail. this will only function in the event of software existing to support this feature.

Voltage, Current and Fault Sensing

The battery voltage and current reported by both bricks can be measured by the FMU. In addition, the 5V unregulated supply rail can be measured (to detect brown- out conditions). IO can measure the servo power rail voltage.

Over-current conditions on the peripheral power ports can be detected by the FMU. Hardware lock-out prevents damage due to persistent short-circuits on these ports. The lock- out can be reset by FMU software. The under/over voltage supervisor for FMU provides an output that is used to hold FMU in reset during brown-out events.

EMI Filtering and Transient Protection

• (on the normal Base Board, must be specified for externally supplied base boards.）

EMI filtering is provided at key points in the system using high-insertion-loss pass- through filters. These filters are paired with TVS diodes at the peripheral connectors to suppress power transients.

Reverse polarity protection is provided at each of the power inputs. USB signals are filtered and terminated with a combined termination/TVS array.

Most digital peripheral signals (all PWM outputs, serial ports, I2C port) are driven using ESD-enhanced buffers and feature series blocking resistors to reduce the risk of damage due to transients or accidental misconnections.

List of features The Cube

• Four set IMU's

• One onboard compass

• Three Barometers

• Dual Power input

  • This removes the option of redundancy from the Servo rail and replaces it with a dedicated second power plug

  • A dedicated power protection Zener diode and Fet have been added to protect from voltages over 5.6v being applied to Aux input 2

  • This is only on the "PRO" carrier board mini carrier board still draws the backup from the servo rail.

• Dual external I2C

  • This allows for connection of items to either I2C port, potentially allowing two GPS / Mag units to be plugged in without the Mags conflicting.

• Power monitoring pins are now routed to the I/O chip, these will allow for the logging of power events during an inflight reboot.

2024-02-08