The unit will need to be wired as follows (this will be similar for other H-bridge type controllers, but check with the relevant datasheet if unsure).

The following table shows how the motors and motor power supply connect to the H-bridge controller module:

The following table shows how the H-bridge controller module connects to the Raspberry Pi:

It is recommended that you keep the pull-up resistor jumpers on (UR1-UR4) and allow the motor supply to power the onboard voltage regulator, which will in turn power the L298N controller (jumper 5V_EN). The onboard regulator (the 78M05 device) can supply up to 500 mA, enough for the L298N controller plus any additional circuits, such as an I/O expander (see the There's more... section for more information). Both the ENA and ENB pins should be disconnected (the motor output will stay enabled by default).

You will need to make the following changes to the previous rover_drivefwd.py script (you can save it as rover_drive.py).

At the top of the file, redefine PINS, as follows:

PINS=[15,16,18,22]   # PINS=[L_FWD,L_BWD,R_FWD,R_BWD] 

And update the control patterns, as follows:

FWD=[ON,OFF,ON,OFF] 
BWD=[OFF,ON,OFF,ON] 
RIGHT=[OFF,ON,ON,OFF] 
LEFT=[ON,OFF,OFF,ON] 

Next, we need to add the backwards command to cmd(), as follows:

  def cmd(self,char,step=STEP): 
    if char == 'f': 
      self.drive(FWD,step) 
    elif char == 'b': 
      self.drive(BWD,step) 
    elif char == 'r': 
      self.drive(RIGHT,step) 
    elif char == 'l': 
      self.drive(LEFT,step) 
    elif char == '#': 
      time.sleep(step) 

Finally, we can update the prompt that we have within the main() function to include b (backwards) as an option, as follows:

print("Enter CMDs [f,b,r,l,#]:")