Generic EUC GD32F130 microcontroller

This generic EUC was bought on Ebay and was really cheap (280€ including the tax and shipping to Portugal, on January 2016).

It is underpowered and slow, even if the battery, motor and controller board seem to be similar with other more powerful generic EUCs. As a guess, seems that the lack of power is due to a low current configuration on the firmware.

Although the board uses GD32F130 microcontroller, which is a chinese clone of STM32F030 microcontroller (See more here about this.), it is very similar with other generic EUC boards:

Also the board have a 4 pin header for "F_WRITE" and another for "DEBUG" that I bet is the serial port connection!!! There is no data out on the debug port while the firmware is running.

Pictures of electrical signals

Yellow: hall sensor signal. Blue: motor phase 1 signal. The motor was running at a "high speed". The duty-cycle of the PWM signal were almost 95%:

Here we can see that there is a linear transition of the duty-cycle value, when the change on the hall sensor value. This is the first time I see such linear transition on a generic EUC:

Here the PWM frequency:

Yellow: motor phase 1 signal. Blue: motor phase 2 signal. Here the motor was stopped:

And here with some rotation: