This board use

GPIO 17,18,27,22 for MA1, MB1

GPIO 23, 24, 25, 4 for MA2, MB2

GPIO 5, 6,12,13 for MA3,MB3

GPIO 16,19,20,21 for MA4,MB4

2 extra i2c input for sensors  (5V or 3v3) (5V port with Level converter)

(1) Scratch PWM command mode

A - GPIO 16,19  Motor A B - GPIO 20,21 Motor B

C - GPIO 5,6  Motor C D - GPIO 12,13 Motor D

command "BPM"+"Motor Name"+ "speed"

speed (0) stop

speed (10 ~100) clockwise

speed (-10 ~ -100) anticlockwise

(2) Scratch GPIO command mode