STM32F405RGT6
Brand: ST
The STM32F405RGT6 is the original MCU at the heart of Pixhawk 1 (PX4FMUv2) and Pixhawk 2.4.x (PX4FMUv2) — the reference hardware platforms that defined the PX4 and ArduPilot open-source drone autopilot ecosystems. Its Cortex-M4F core with hardware floating-point unit enables fast single-precision math for PID control loops, Extended Kalman Filters (EKF2/EKF3 in ArduPilot), and attitude estimation at update rates exceeding 8 kHz. The 168 MHz clock, ART Accelerator (zero-wait-state Flash execution), and 192 KB SRAM provide ample headroom for full-stack autopilot firmware with GPS waypoint navigation, telemetry streaming, and onboard logging.
STM32F405 — the chip powering Pixhawk 1 and Pixhawk 2.4.x, the most widely deployed open-source drone autopilot hardware in the world.
Product Specifications
STM32F405RGT6 — ARM Cortex-M4F MCU for Pixhawk / PX4 / ArduPilot Drone Autopilots by STMicroelectronics
The STM32F405RGT6 is STMicroelectronics' high-performance 32-bit ARM Cortex-M4F microcontroller running at 168 MHz with 1 MB Flash and 192 KB (128 KB + 64 KB CCM) in a LQFP-64 (10×10 mm, 0.5 mm pitch). It is the legendary MCU behind the Pixhawk 1 and Pixhawk 2.4.x open-source drone autopilots — the reference hardware platforms for PX4 and ArduPilot firmware. With hardware single-precision FPU, ART Accelerator, dual CAN 2.0B, SDIO, and industrial temperature range (−40°C to +85°C), it remains the most proven silicon for professional multirotor, fixed-wing, and VTOL UAV platforms worldwide.
Part Number Decoded — Field by Field
| Field | Value | Meaning |
|---|---|---|
| STM32 | Product Family | STMicroelectronics 32-bit ARM-based MCU |
| F | Core Type | Foundation — high-performance series (ARM Cortex-M4F with FPU) |
| 405 | Sub-Family | 405 Performance Line — 168 MHz Cortex-M4F with FPU, dual CAN, SDIO. Powers Pixhawk 1 & 2.4.x |
| R | Pin Count | 64 pins (LQFP-64) |
| G | Flash Size | 1 MB |
| LQFP | Package | LQFP (Low-profile Quad Flat Package) |
| 6 | Temperature Range | −40°C to +85°C (industrial) |
Quick Specifications
| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Part Number | STM32F405RGT6 |
| Core | ARM Cortex-M4F |
| Max Clock | 168 MHz |
| Flash | 1 MB |
| SRAM | 192 KB (128 KB + 64 KB CCM) |
| Package | LQFP-64 (10×10 mm, 0.5 mm pitch) |
| Supply Voltage | 1.8V – 3.6V |
| Operating Temperature | −40°C to +85°C |
| GPIO | 51 |
| ADC | 3× 12-bit (16 channels) |
| DAC | 2× 12-bit |
| Timers | 12× 16-bit, 2× 32-bit, 2× watchdog, 1× SysTick |
| Communication | 4× USART, 2× UART, 3× SPI (37.5 Mbit/s), 3× I²C, 2× CAN 2.0B, 1× USB 2.0 OTG FS, 1× SDIO |
| DMA | 2× 8-channel (16 streams) |
| Debug | SWD + JTAG |
Product Overview
The STM32F405RGT6 is the original MCU at the heart of Pixhawk 1 (PX4FMUv2) and Pixhawk 2.4.x (PX4FMUv2) — the reference hardware platforms that defined the PX4 and ArduPilot open-source drone autopilot ecosystems. Its Cortex-M4F core with hardware floating-point unit enables fast single-precision math for PID control loops, Extended Kalman Filters (EKF2/EKF3 in ArduPilot), and attitude estimation at update rates exceeding 8 kHz. The 168 MHz clock, ART Accelerator (zero-wait-state Flash execution), and 192 KB SRAM provide ample headroom for full-stack autopilot firmware with GPS waypoint navigation, telemetry streaming, and onboard logging.
STM32F405 — the chip powering Pixhawk 1 and Pixhawk 2.4.x, the most widely deployed open-source drone autopilot hardware in the world.
Key Features & Benefits
168 MHz Cortex-M4F + Hardware FPU — PX4 & ArduPilot Native
The Cortex-M4F core with single-precision hardware floating-point unit executes PID controllers, Kalman filters (EKF2/EKF3), and quaternion attitude estimation in native float — no software emulation overhead. At 168 MHz with the ART Accelerator delivering zero-wait-state Flash execution, the F405 sustains IMU update rates up to 8 kHz on dual-redundant IMU configurations (ICM-20689 + ICM-20602 or MPU6000 pairs) as used in Pixhawk 2.4.8.
1 MB Flash + 192 KB SRAM — Full ArduPilot / PX4 Stack
With 1 MB of embedded Flash and 192 KB of SRAM (128 KB system + 64 KB CCM tightly-coupled memory), the F405 comfortably runs the full ArduPilot feature set: EKF3 state estimation, L1 navigation controller, terrain following, geofencing, onboard microSD logging, MAVLink telemetry routing, and Lua scripting. The 64 KB CCM RAM provides deterministic zero-wait-state access for the real-time flight control loop — critical for maintaining loop timing under heavy telemetry and logging I/O.
Dual CAN 2.0B — UAVCAN / DroneCAN Ecosystem
Two independent CAN 2.0B interfaces enable connection to the UAVCAN/DroneCAN peripheral ecosystem: GPS/compass modules (Here3, Zubax GNSS), airspeed sensors, ESC telemetry nodes, power modules, and servo controllers — all on a single shared bus with hardware-level priority arbitration. This modular architecture, pioneered on Pixhawk 2.1 (Cube), separates safety-critical peripherals from I²C/SPI bus contention.
SDIO Interface — High-Speed Onboard Blackbox Logging
The SDIO (Secure Digital I/O) interface connects directly to a microSD card slot without SPI bit-banging, enabling high-bandwidth blackbox logging at sensor-native rates. Pixhawk-class platforms use this to log raw IMU data at 1 kHz, GPS position at 10 Hz, and all RC/PWM inputs — essential for post-flight PID tuning, vibration analysis (FFT), and crash forensics.
3× 12-bit ADC + 2× DAC — Advanced Sensor & Actuator Pipeline
Three independent 12-bit ADCs with up to 16 channels sample analog sensors (battery voltage/current via resistive dividers, airspeed via differential pressure transducers, analog RSSI) simultaneously. Two 12-bit DACs provide analog control outputs for gimbal stabilization servos and analog OSD overlay circuits — reducing external op-amp and DAC component count.
Advanced Timers with 6+ PWM Channels — Quad to Octocopter
Two 32-bit and twelve 16-bit timers, including advanced-control timers with complementary outputs and programmable dead-time insertion, drive up to 8 independent PWM channels for multirotor motor control and additional servo outputs for fixed-wing (aileron, elevator, rudder, throttle, flaps). Supports Oneshot125, Oneshot42, Multishot, and DShot150/300/600 protocols via hardware timer DMA bursts.
Target Applications
Pixhawk 1 / Pixhawk 2.4.x Flight Controller
The STM32F405 is the reference MCU for the original PX4FMUv2 design powering Pixhawk 1 and all 2.4.x revisions (2.4.5 through 2.4.8). These platforms run PX4 v1.x and ArduPilot (Copter, Plane, Rover) on quadcopters, hexacopters, VTOL tilt-rotors, and fixed-wing mapping UAVs worldwide. The F405's proven real-time performance, dual CAN buses, and SDIO logging make it the gold standard for professional-grade open-source autopilots.
PX4 / ArduPilot Reference Hardware
As the silicon foundation of the PX4 FMUv2 and FMUv3 reference designs, the STM32F405RGT6 is the baseline MCU used in PX4's hardware abstraction layer (HAL) and NuttX RTOS port. All PX4 drivers — IMU (MPU6000, ICM-20602, ICM-20689, BMI055), barometer (MS5611, BMP280), magnetometer (HMC5883L, IST8310), GPS (u-blox NEO-M8N/M9N), and RC (S.Bus, DSM, PPM) — are tested and validated on this silicon.
Matek H743 / Omnibus F4 Pro / Kakute F4
Beyond the Pixhawk family, the F405 powers popular miniaturized flight controller boards: Matek F405-Wing (fixed-wing), Omnibus F4 Pro (racing/hybrid), Kakute F4 AIO (FPV), and Diatone Mamba F405. These boards run Betaflight, iNav, and ArduPilot on platforms ranging from 3″ micro quads to 2-meter wingspan mapping aircraft.
Professional Surveying & Inspection UAVs
For photogrammetry, LiDAR scanning, and thermal inspection drones, the F405's deterministic real-time performance ensures precise waypoint tracking and camera triggering via PWM/relay outputs. The dual CAN buses integrate RTK GPS (u-blox F9P), laser altimeters (LeddarTech, TF-Luna via UART), and gimbal controllers into a synchronized navigation pipeline.
Robotics & Ground Vehicle Autopilots
ArduPilot Rover on STM32F405-based boards provides autonomous navigation for agricultural robots, warehouse AGVs, and outdoor exploration platforms. The high GPIO count (51 pins on R-package) supports encoder inputs, servo outputs for skid-steering/differential drive, ultrasonic sensors, and CAN-based motor controllers (ODrive, VESC) — all within a single-chip solution.
F405 Series Variant Comparison
| Feature | STM32F405RGT6 | STM32F405VGT6 | STM32F405ZGT6 | STM32F405VGT7 |
|---|---|---|---|---|
| Package | LQFP-64 | LQFP-100 | LQFP-144 | LQFP-100 |
| Flash | 1 MB | 1 MB | 1 MB | 1 MB |
| SRAM | 192 KB | 192 KB | 192 KB | 192 KB |
| GPIO | 51 | 82 | 114 | 82 |
| FPU | Yes (Cortex-M4F) | Yes (Cortex-M4F) | Yes (Cortex-M4F) | Yes (Cortex-M4F) |
| Temperature | −40°C to +85°C | −40°C to +85°C | −40°C to +85°C | −40°C to +105°C |
| Best For | Pixhawk 1, mid-size FC | Full Pixhawk, rich I/O | Pixhawk 2.4.x, max GPIO | High-temp industrial UAV |
STM32F405RGT6 vs Competing Drone Autopilot MCUs
| Feature | STM32F405RGT6 (ST) | STM32F427VGT6 (ST) | STM32H743VIT6 (ST) | ATSAM3X8E (Microchip) |
|---|---|---|---|---|
| Core | ARM Cortex-M4F @ 168 MHz | ARM Cortex-M4F @ 180 MHz | ARM Cortex-M7F @ 480 MHz | ARM Cortex-M3 @ 84 MHz |
| Flash / SRAM | 1 MB / 192 KB | 1 MB / 256 KB | 2 MB / 1 MB | 512 KB / 100 KB |
| FPU | Yes (SP) | Yes (SP) | Yes (DP + SP) | No |
| CAN Bus | 2× CAN 2.0B | 2× CAN 2.0B | 2× CAN-FD | 1× CAN 2.0B |
| Pixhawk Target | FMUv2 / FMUv3 | FMUv3 / FMUv4 | FMUv5 / FMUv6X | — (ArduPilot legacy) |
| Availability (Q3 2026) | Excellent, 8–12 wk lead | Good, 10–14 wk lead | Good, 12–16 wk lead | Limited (NRND) |
Frequently Asked Questions
What Pixhawk hardware versions use the STM32F405RGT6?
The STM32F405RGT6 is the MCU on Pixhawk 1 (PX4FMUv2, LQFP-64), Pixhawk 2.4.5 through 2.4.8, and the original 3DR Pixhawk. The 2.4.x series uses the LQFP-100 or LQFP-144 package variants (VGT6/ZGT6) for additional GPIO. All of these are F405 silicon. The move to F427/H743 on Pixhawk 2.1 (Cube) and Pixhawk 4/5 added more Flash/RAM and faster cores, but the F405-based 2.4.x remains the most widely cloned and field-deployed autopilot platform.
Can the STM32F405 run ArduPilot 4.5+ with EKF3?
Yes. The STM32F405 with 1 MB Flash and 192 KB SRAM fully supports ArduPilot 4.5+ running EKF3 (the default state estimator since Copter 4.1). The hardware FPU handles the 24-state EKF covariance propagation in single-precision float at full sensor rate. Memory usage for a typical Copter build with EKF3, terrain following, geofence, OSD, and MAVLink telemetry is approximately 700–850 KB Flash and 110–140 KB SRAM — well within F405 limits.
What is the CCM RAM and why does it matter for drones?
The 64 KB Core-Coupled Memory (CCM) is a block of zero-wait-state SRAM tightly coupled to the Cortex-M4F core, separate from the main 128 KB system SRAM. In PX4 and ArduPilot, the real-time flight control loop (sensor read → EKF update → PID compute → mixer → PWM output) is placed in CCM to guarantee deterministic timing regardless of DMA/telemetry/SDIO activity on the main bus matrix. This architectural feature is critical for maintaining stable loop rates (400–800 Hz on Pixhawk) under heavy I/O load.
How does the STM32F405 compare to the F427 for Pixhawk designs?
The F427 is a direct upgrade path: 180 MHz vs 168 MHz (+7%), 256 KB vs 192 KB SRAM (+33%), and 2 MB Flash options (II/VI/ZI) vs 1 MB max on F405. Both share the same Cortex-M4F core with FPU. For Pixhawk designs, the F427 is used on Pixhawk 2.1 (Cube) for the additional Flash needed by PX4's modular driver architecture. The F405 remains the better choice for cost-optimized designs where 1 MB Flash is sufficient.
Is the STM32F405 still in active production in 2026?
Yes. The STM32F405 remains in full active production and is not NRND (Not Recommended for New Design). It is a cornerstone of ST's high-performance MCU portfolio with sustained demand from the drone, industrial motor control, and medical device sectors. Lead times as of Q3 2026 are 8–12 weeks for tray quantities, with excellent spot-market availability through Asian distribution channels.
Ordering Information
| Orderable Part Number | Package | Packaging | Temperature |
|---|---|---|---|
| STM32F405RGT6 | LQFP-64 (10×10 mm, 0.5 mm pitch) | Tray | −40°C to +85°C |
| STM32F405RGT6TR | LQFP-64 (10×10 mm, 0.5 mm pitch) | Tape & Reel | −40°C to +85°C |
Design Resources
Datasheet (DS8626): STM32F405xx/STM32F407xx — Complete datasheet with pin definitions, electrical characteristics, and package drawings.
Reference Manual (RM0090): STM32F405/415, STM32F407/417, STM32F427/437 advanced ARM-based 32-bit MCUs.
Pixhawk FMUv2 Hardware: PX4 FMUv2 reference design schematics and BOM — the original open-source Pixhawk hardware specification.
ArduPilot F4 Lightning: Build instructions and bootloader for ArduPilot on STM32F405-based flight controllers.
STM32CubeIDE: Free ST development environment with graphical pinout/clock configurator and GCC toolchain.
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