System Architecture

The Cube system architecture incorporates two functional blocks into a single physical module.

PWM Outputs

Eight PWM outputs are connected to the I/O.

• Can be directly controlled by the I/O via the R/C input and onboard mixing even if the FMU is not active (failsafe/manual mode).

• Supports multiple update rates in three groups (one group of four outputs and two groups of two outputs).

• Supports signal rates reaching up to 400Hz.

• Output only.

• Each PWM output can drive up to 50mA, but the total limit for all eight outputs is 100mA.

Six PWM outputs are connected to the FMU.

• Supports reduced update latency.

• Cannot be controlled by the I/O in failsafe conditions.

• Supports multiple update rates in two groups (one group of four and one group of two).

All the PWM outputs are EDS-protected and are designed to survive accidental servo misconnection without damage. 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.

The I/O PWM outputs are not high-power outputs. The PWM drivers are only designed to drive servos and similar logic inputs and do not include relays or LEDs.

Peripheral Ports

All peripherals are connected through a single 80-pin connector. The peripherals are connected via a baseboard that can be customized for each application.

Base Board

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

Serial Ports

• Five serial ports are provided.

• The serial ports operate at a 3.3V CMOS logic level. They are 5V tolerant, buffered, and ESD-protected.

• Serial 1 and 2 feature full flow control.

• Serial 3 is recommended to function as a GPS port. A safety button and possibly a safety LED are included. An I2C for the compass and RGB LED is also provided.

• Serial 4 has an I2C on the second bus, allowing two compass modules to be connected simultaneously.

• Serial 5 is available as a header underneath the board. It is used for the onboard ADSB-IN receiver that is featured on newer carrier boards.

SPI Port

• Not buffered. 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.

Analog Inputs

• Analogue 1-3 are protected against inputs up to 12V, but scaled for 0-3.3V inputs.

• The RSSI input supports either PWM or analog RSSI. As this input shares a pin with the S.Bus output, only one of them may be connected at a time.

CPPM, S.Bus and DSM/Spektrum Input

These inputs remain unchanged from the previous versions.

CAN Ports

The CAN ports are standard CAN Bus. Termination for one end of the bus is fixed on board. The drivers are onboard the FMU.

Piezo Port

The piezo port drives most piezo elements in the 5 - 300nF range at up to 35V. It is extremely loud, where the achievable sound pressure level is limited by the sensitivity of the piezo element being driven.

I2C

I2C is direct driven, un-buffered, and pulled up to 3.3v onboard the FMU.

Sensors

All flight sensors in The Cube are connected via SPI.

Cube Type	Life Cycle	IMU1	IMU2	IMU3	Barometer1	Barometer2
Cube Black Cube BlueF4 Cube Green	EOL	MPU9250	LSM303D/L3GD20	MPU9250	MS5611	MS6511
Cube Black+	EOL	MPU9250	ICM20602	ICM20948	MS5611	MS5611
Cube PurpleF4	EOL	MPU9250	NA	NA	MS5611	NA
CubePurpleH7	ACTIVE	ICM20649	NA	NA	MS5611	NA
Cube Orange Cube Yellow Cube BlueH7	ACTIVE	ICM20649	ICM20602	ICM20948	MS5611	MS5611
Cube Orange+	ACTIVE	ICM45686 / ICM20649	ICM20948 / ICM42688 / ICM45686_EXT2	ICM42688 / ICM45686	MS5611	MS5611

• IMU1 is not isolated.

• IMU2 and IMU3 are isolated.

• Data-ready signals from any of the sensors are NOT ROUTED on the Isolated IMU.