PCB Designer (Drone Flight Controller)

Hardware Requirements Specification
Project: Custom High-Performance Flight Controller PCB
1 Core Processing & Architecture
• Microcontroller (MCU): STM32H7 Single-Core High-Performance Series (100-pin or 144-
pin LQFP/BGA package configuration). Core architecture must feature an ARM Cortex-M7
running at up to 480 MHz with a double-precision Floating Point Unit (FPU).
• Debugging Interface: 1x standard SWD debug port (GND, SWDIO, SWCLK, 3V3) brought
out to dedicated test points or a low-profile header.
2 Memory & Storage Architecture
• Configuration Parameter Storage: 32 Mbit (4 MB) Ferroelectric RAM (FRAM) non-volatile
memory. Must be dedicated to critical parameter storage and real-time state saving due
to its ultra-high endurance and zero write-delay capabilities.
• Blackbox Data Logging: 1x Micro SD Card Slot. Must be routed via a dedicated highspeed SDMMC interface (preferred for high-throughput 4-bit parallel data transfer) or a
high-speed SPI bus to capture high-frequency flight dynamics, sensor telemetry, and PID
loops without dropping frames.
3 Power Management System (PMIC)
• Input Voltage Range: 7.4V to 75.6V direct input (supporting 2S up to 18S LiPo battery
architectures).
• Regulation Stage: A high-efficiency, wide-input synchronous buck regulator stage to step
down the high-voltage input to clean 5V and 3.3V logic rails.
• EMI & Transient Protection: Aggressive input Transient Voltage Suppression (TVS) diodes
and robust LC filtering networks are mandatory to suppress massive flyback voltage spikes
and electromagnetic noise generated by heavy-lift ESCs and high-current propulsion systems.
• Visual Indicators: Onboard dedicated Power LEDs (for 5V/3.3V status verification) and
system status LEDs.
4 Sensor Suite & EMI Mitigation
• Primary IMU: Bosch BMI088 (Automotive-grade, 6-axis). Strict Placement: Must be positioned precisely at the geometric center of the PCB.
• Magnetometer: IST8310.
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• Barometer: STMicroelectronics LPS22HB high-precision pressure sensor.
• EMI Shielding & Grounding: All three sensors must be heavily isolated from electromagnetic interference. The layout requires continuous, uninterrupted internal ground planes
directly beneath the sensor block, with physical trace separation from high-frequency
switching lines. A footprint for an optional localized surface-mount RF shield (Faraday
cage) enveloping the entire sensor cluster must be included.
5 Input / Output Interfaces & Interconnects
• Connector Standard: Peripheral, telemetry, and CAN I/O ports must utilize JST GH 1.25mm
locking connectors to secure connections against severe airframe vibrations.
• Motor Control: 12x hardware PWM output channels utilizing standard 2.54mm pitch 3-pin
headers (Signal, Positive, Negative). Must support standard PWM and high-speed DShot
protocols. Signal lines must be routed away from the sensitive I2C/SPI sensor buses.
• Serial & Telemetry Ports:
– 3x UART ports designated for Telemetry 1, Telemetry 2, and GPS.
– 1x I2C port dedicated for an external compass/peripheral connection.
– 2x CAN ports compatible with DroneCAN/UAVCAN protocols (requiring onboard CAN
FD transceivers).
• Receiver Input: 1x UART port dedicated to SBUS input (configured for RX-only operation
with an integrated hardware inverter circuit on the RX line).
• Configuration Interface: 1x USB Type-C port, featuring robust ESD protection arrays situated immediately at the physical connector ingress point.