Creating a FlyingF4 from scratch

Murilo Pontes edited this page Feb 23, 2016 · 22 revisions

Step by step

  1. Buy an STM32F4Discovery
  2. Buy a shield with MPU6050, HMC5883, MS5611: GY-86 is a good candidate
  3. Wiring
  4. Flash the bootloader
  5. Flash the firmware

You now have a fully functional FlyingF4. Enjoy!


  1. by Lilvinz outdated
  2. by Murix updated

FrSky X8R SBUS input

To use UART1 as SBUS invert is required invert SBUS signal.

sbus inverter

** BOM List

  • 1 x 4.7k ohm resistor
  • 1 x 10k ohm resistor
  • 1 x 2N3904 NPN transistor

FrSky X8R SPort Telemetry

To use UART3 as SPort Telemetry is required invert both RX and TX.

X8R Smart Port inverter


Blink codes for the red LED

  • 1 pulse - flash chip
  • 2 pulses - MPU6050
  • 3 pulses - HMC5883
  • 4 pulses - MS5611
  • 5 pulses - gyro I2C bus locked
  • 6 pulses - mag/baro I2C bus locked

Notes about current release

Currently UART4, UART5 and ADC are not implemented.

External SPI flash is disabled in default build.

SBUS input in UART1 require external sbus inverter.

UART1 is RX only

FrSky Hub Sensor in any uart required external single inverter.

FrSky Smart port work only in uart 2 and 3 and require dual inverter.

Wiring / Pinout

Flying F4 pinout

  • X8R SBus required one single channel inverter
  • X8R Sport required dual channel inverter
  • D8R-II-Plus required one single channel inverter
  • ADC max voltage is 3.3V, APM PM output 3.3V @ 60A
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