> For the complete documentation index, see [llms.txt](https://wiki.cbunmanned.com/wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.cbunmanned.com/wiki/products-eol/cbu-cm405-fc-eol.md).

# CBU-CM405-FC (EOL)

<div><figure><img src="/files/bHBuWms9dwpLh8wYrAnc" alt=""><figcaption></figcaption></figure> <figure><img src="/files/MLcAFl95roRvLJQrL7Ke" alt=""><figcaption></figcaption></figure></div>

[Purchase on the Store](https://cbunmanned.com)

The CM405-FC is designed to simplify and minimize the physical size of UAV control systems. By incorporating common accessories onto a single circuit board system-to-system wiring is dramatically reduced, minimising weight and failure points. With tight integration for a [Raspberry Pi Compute Module 4](https://www.raspberrypi.com/products/compute-module-4/?variant=raspberry-pi-cm4001000#:~:text=Broadcom%20BCM2711%20quad,PCB%20trace%20antenna), high demand onboard processing comes in a tiny form factor!&#x20;

**Dimensions**: 55x40x16mm (48x33mm M2.5 Mounting)

**Weight**: (Stack Total = 29g)

CM405-FC = 16g

CM405-FC-BO =2g

CM4 = 11g&#x20;

## General Overview

The flight controller can be generally split into 2 halves:&#x20;

1\) The STM32F405 runs ArduPilot or Px4 and calculates all the algorithms needed for stable flight. (Shown Yellow in the Architectural Map)

2\) The Raspberry Pi Compute Module 4 acts as a companion computer connected to the STM32 over UART and allows more advanced I/O and flight manipulation. (Shown Blue in the Architectural Map)

<figure><img src="/files/CuSmuBk2I0CRXegAhzhQ" alt=""><figcaption><p>Architectural Map</p></figcaption></figure>

## I/O and Sensors

### STM32

* 2x IMU (1x ICM20602, 1x BMI270)
* 1x Barometer (BMP280)
* 5x UART Serial (1x Externally Jumped to the CM4, 1x For SBus or Serial RC)
* 1x I2C
* 6x PWM (1-6 through mezzanine, 5-6 through Female Header)
* Micro SD For Logging

### Raspberry Pi Compute Module 4

* 2x CSI Camera (Pi Zero Connector)
* 4x USB 2.0 Host (Male Header)
* Micro SD Card for without EMMC
* 1x UART Serial (Externally Jumped to the STM32)
* Full 40 Pin GPIO (Broken out to solder pads, ONLY compatible with CM405-FC-BO)

## ESC Mezzanine

### CM405-FC-BO

<div><figure><img src="/files/XsRLMyksvgJ85vVfCluz" alt=""><figcaption></figcaption></figure> <figure><img src="/files/al47tENXhfFvOBNCBdK9" alt=""><figcaption></figcaption></figure> <figure><img src="/files/9l5GlTenQJQZR99t54TG" alt=""><figcaption></figcaption></figure></div>

All new purchases will come with a CM405-FC-BO, which simply connects onto the top of the flight controller and breaks out into an 8 pin sh1.0 connector for power, current and PWM 1-4. The breakout also features an integrated Voltage sensor.

### CM405-FC-ESC

<figure><img src="/files/2BECmqnkiGLm91FAjvxj" alt=""><figcaption><p>CM405-ESC-4s4c</p></figcaption></figure>

A range of compatible BL-Heli ESCs are available with varying applications.

* CM405-ESC-4s4c. 4 channel, 2-4s 20 Amp ESC (Quadcopters)
* CM405-ESC-4s2c. 2 channel, 2-4s 20 Amp ESC with 4 servo channels and dedicated servo BEC (Fixed wing)