Specifications
Karu has the full sensor set revision 3 (FMU, VMU) of the Pixhawk v6X-RT standard.
Processor and memory
| Part | Specification |
|---|---|
| Processor | NXP i.MX RT1176: Arm Cortex-M7 at 1 GHz, Cortex-M4 at 400 MHz |
| Memory | 2 MB RAM, 64 MB external flash |
| Secure element | NXP EdgeLock SE052F: CC EAL 6+, IEC 62443-4-2, FIPS 140-3 |
The secure element stores keys and verifies that the firmware is authentic. PX4 reaches it through a driver module.
Sensors
| Sensor | Part |
|---|---|
| IMU | two ICM-45686, one BMI088 |
| Barometer | two BMP390 |
| Magnetometer | BMM350 |
The three IMUs are in separate domains, each with its own bus and its own power control, so a failed sensor cannot stop the other two. Mechanical isolation inside the module damps the high-frequency vibration that spoils attitude estimation on a noisy airframe.
Running one estimator per IMU is in Sensors and redundancy.
Interfaces
The module meets the Pixhawk Autopilot Bus on the 100-pin and 50-pin connectors to the baseboard. The baseboard brings out the following. Pin tables and bus assignments are in Baseboard ports.
| Interface | Ports | Detail |
|---|---|---|
| Power input | 2 | POWER1 and POWER2, each with its own I2C bus for the power module’s monitor |
| PWM output | 12 | outputs 1 to 8 also do DShot |
| Serial | 4 | TELEM1, TELEM2 and TELEM3 with hardware flow control, TELEM1 on its own 5 V rail; UART & I2C adds I2C6 and a GPIO line for an external NFC reader |
| GNSS | 2 | GPS1 with compass I2C, safety switch and buzzer; GPS2 with compass I2C |
| CAN | 3 | three independent buses |
| Ethernet | 1 | 100BASE-T1 at 100 Mbit/s over one twisted pair, transformerless |
| SPI | 1 | two chip selects, two data-ready lines, sync and reset |
| I2C | 1 | I2C6, the bus the UART & I2C port also uses |
| RC input | 1 | SBUS or PPM on RC IN / AUX position 2, or Spektrum on DSM RC; position 1 outputs SBUS |
| Analogue and IO | 1 | two analogue inputs, a PWM capture input, bootloader, reset and armed lines |
| Debug | 1 | console and SWD |
| USB | 1 | USB-C, with a header of the same signals beside it |
| NFC | 1 | antenna coil for the secure element |
Electrical
| Input | Range |
|---|---|
| POWER1, POWER2, USB | 4.8 to 5.4 V, 6 V absolute maximum |
| Servo rail | 0 to 10 V |
The 5 V rails that feed the ports have their own limits, see Peripheral rails.