Mono :: Motor driver

Goal

The goal of this Mono iteration is replacing the motor driver. In the earlier published post it was mentioned that L298N motor driver creates a significant voltage drop.

Well, I decided to go with the TB6612FNG chip as of the Pololu motor driver.

Designing the Mono driving module

Requirements

Okay, we have

four motors
and two motor drivers with the following pinout.

Pin on the left	Description	I	Description	Pin of the right
`GND`	Logic ground	I	PWM for the engine A	`PWMA`
`VCC`	Logic VCC 2.7V-5.5V	I	Direction Pin 2 Engine A	`AIN2`
`AO1`	Engine A output 1	I	Direction Pin 1 Engine A	`AIN1`
`AO2`	Engine A output 2	I	Standby Pin	`STBY`
`BO1`	Engine B output 1	I	Direction Pin 1 Engine B	`BIN1`
`BO2`	Engine B output 2	I	Direction Pin 2 Engine B	`BIN2`
`VMOT`	Engines V_in 4.5V-13.5V	I	PWM for the engine B	`PWMB`
`GND`	Engines ground	I	PWMs and xINy ground	`GND`

Therefore, module should supply following communications:

power supply for engines (VMOT / GND - power-supply 7.4V);
power supply for logic (VCC / GND - power-supply 5V);
speed control PWMs x4 (PWMA, PWMB, GND - PCA9685 PWM channels);
directions pins x2 per motor, x8 in total (AIN1, AIN2, BIN1, BIN2 - Raspberry Pi GPIO digital pins);
standby pins x2 (STBY - Raspberry Pi GPIO digital pin; enables / disables both motors);
output engine connectors as terminals x4 (AO1, AO2, BO1, BO2 - engines).