The 305ap is a compact, high-performance flight controller for multirotor, fixed-wing, and rover platforms. It runs PX4 on NuttX RTOS, built around the STM32H743VIH6. The board follows a 30.5 mm mounting pattern and is aimed at the PX4 ecosystem with dual FDCAN, dual telemetry, a dedicated VTX power rail, and a full onboard sensor suite with redundant IMUs.
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Specifications
Processor
| Parameter | Value |
|---|
| MCU | STM32H743VIH6 (TFBGA100) |
| Architecture | Arm Cortex-M7, double-precision FPU / DSP |
| Clock | 24 MHz HSE → 480 MHz core (via PLL) |
| Flash | 2 MB |
| RAM | Up to 1 MB |
Sensors
| Sensor | Part | Interface |
|---|
| IMU (×2, redundant) | ST LSM6DSV (primary) / TDK InvenSense ICM-45686 (fallback) | SPI2, SPI3 |
| Barometer | Bosch BMP581 | SPI1 |
| Magnetometer | MEMSIC MMC5983MA | I2C1 |
Connectivity
| Interface | Details |
|---|
| UARTs | 7 (USART1/2/3, UART4/5/6/7) |
| CAN | 2× FDCAN (FDCAN1, FDCAN2) via SIT1044T FD transceivers |
| I2C | 3 buses (internal mag, GPS port, external port) |
| SPI | 4 buses (baro, IMU ×2, external expansion) |
| PWM outputs | 8 (TIM1/2/3/4) |
| RC input | UART5 single-wire (SBUS, CRSF, PPM) |
| USB | USB-C, USB 2.0 FS device (OTG FS PHY) |
| SD card | SDMMC1 (native 4-bit SDIO) |
Power
| Rail | Source | Purpose |
|---|
| VBAT | External (2S–6S) | Main input with ideal-diode protection |
| 9 V | AP63357 buck | VTX / accessories |
| 5 V | AP63357 buck | Peripherals, connectors, CAN, GPS |
| 3.3 V | AP63357 buck | Digital logic, MCU |
| 3.3 V LDO | RT9193 (quiet) | IMUs, barometer, magnetometer |
| 5 V select | TPS2116 mux | Auto-selects USB 5 V or 5 V switcher |
Physical
| Parameter | Value |
|---|
| Form factor | 30.5 mm mounting pattern |
| Firmware target | avianautomata_305ap |
Design Notes
- Dual IMUs. Two IMU slots on SPI2 and SPI3. Each slot supports the ST LSM6DSV (primary) or TDK InvenSense ICM-45686 (fallback) — firmware auto-detects at boot via WHO_AM_I. PX4 runs sensor voting across both and falls back if one diverges.
- Low-noise sensor rail. The IMUs, barometer, and magnetometer are powered from a separate RT9193 ultra-low-noise 3.3 V LDO, isolated from the main digital 3.3 V switcher via a ferrite bead.
- Wide input voltage. The VBAT path uses an LM74700-Q1 ideal-diode controller with an external N-FET, providing 2S–6S input support with low forward drop and protection against reverse polarity.
- Dedicated 9 V rail. A second AP63357 buck provides a stable 9 V rail for VTX/OSD power, independent of the 5 V peripheral rail.
- Auto USB / battery power. A TPS2116 mux selects between USB 5 V and the onboard 5 V switcher automatically, so the board powers cleanly from USB alone during bench work.
- No onboard current shunt. The ASENSE pin accepts a 0–3.3 V signal from an external current sensor (power module or ESC with current output). No current data is available without one.
- No safety/arm switch. Arming is via RC stick command or GCS only. Set
COM_ARM_SWSBTN appropriately.
- Parameters on SD card. No FRAM. Parameters are stored at
/fs/microsd/params. A card must be inserted for parameters to persist across reboots.
- No inversion stage on RC input. UART5 is single-wire half-duplex. SBUS compatibility depends on PX4's software inversion support for the H7 UART. CRSF and uninverted ELRS are fully supported.
- MCU package. TFBGA100 exposes GPIO ports A–E only. All pin assignments reflect this constraint.