Size:

Some mini 20*20 Flight Controller with M2 holes on the markets, they are not suitable for 5" inch racing frame. Although some are 20*20 size, but outer size are about 36*36 mm. (It's same size with 30*30 Flight Controller)
We want to make a mini 20*20 flight controller with an outer size of 26*26 ~ 30*30 mm and using M3 screws.
Finally, we decided to add LED pads in each corner, outer dimension is 30*30 mm. It is worth to increase the size a little bit to reduce external LED control board.

Core:

MCU is STM32F722RET6 216MHz, F7 is a faster proessor and a lot easier to set up such as inverted signal.
Gyro is MPU6000 6-Axis, to reduce noise and avoid flying into space ಠ_ಠ

Layout:

Logical layout makes welding easier, saving space for assembling parts, reduce annoying excess wires, it's easy to makes for a clean build. 
Left side of the above picture: upper front of the flight controller ⇧
On the right is the bottom of flight controller.

Camera:

Four pads arranged at the front: C+ C- CS CC, can be welded directly to Runcam racer nano 2 or Foxeer Predator micro / nano v5。 CC (one wire camera control), enter camera setting through OSD without any setting.

Receiver:

Solder pads also located at the front, to avoid touching the ground on the left / right side of flight controller when crashing. Four pads G 5V R2 T2, can be welded directly to TBS Crossfire / Tracer。

VTX:

Solder pads located at the rear of the flight controller for easy connection to the antenna.  Four pads V+ V- VS T5, can be welded directly to TBS unify pro32 nano. Smart Audio - set on the Betaflight with T5 UART5, which can setting VTX via OSD.
VTX pit mode power switch - set on the Betaflight, which can turn the VTX ON/OFF with transmitter switch. Benefit for overheat when waiting for race start, and avoid your signal affecting other pilots when you was crashed.


Buzzer:
The + - poles are deliberately separated, which can welded the small buzzer directly to the flight controller without any wires

Motor 5 & 6:
Sometimes the motor has not response, may be just dead for flight controller's motor 1/2/3/4. With pads 5/6, there is no need to reimburse the entire flight controller.


ESC plugs:
Design at the rear bottom, theoretically, the plug wires can be shorter if set at the front, but it will mess around and reduce space for camera installation. Why rear bottom not rear above of flight controller? Because some peoples they tied the capacitor on the ESC main wires, it is easy to hit the ESC plug fall off when crashed.
Sort order of the plug are -  +  1  2  3  4  CRT  TELE, it can be plug directly to Aikon 20x20 ESC. The wires we provided is one side open end, convenient for you to use your favorite


UARTS:

6 UARTS, 4 full UARTS with RX AND TX pins

USB Type C

In 2021, there is no reason still using micro-b, although it's smaller and lighter.

DJI digital FPV

like Freestyle shooting? Simply plug-in DJI system, enjoy HD quality.

LED

LED pads at the four corners, specifically for professional racers to reduce troublesome connections.
(FAI competitions require 40 LEDs)

Voltage

Up to 12S (50V) direct battery power, enough for 4S or 6S.

Packaging

All parts are in a tiny box 35*35mm, extremely lightweight.
Included:  Wizz F7 flight controller,  8 pin ESC cable, 6 pin DJI cable, ,DJI 6pin cable, 6x M3 vibration damping.