Difference between revisions of "Motor Driver HAT"

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main.py: Motor driver code
 
main.py: Motor driver code
  
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DEMO CODE
 
DEMO CODE
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*Instantiate PCA9685 library
 
*Instantiate PCA9685 library
 
  pwm = PCA9685(0x40, debug=True)
 
  pwm = PCA9685(0x40, debug=True)

Revision as of 01:34, 21 January 2022

Motor Driver HAT
Motor-Driver-HAT-intro.JPG

Raspberry Pi Expansion Board, DC Motor
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Introduction

Raspberry Pi Expansion Board, DC Motor , i2c interface

OVERVIE

This module is a motor driver board for Raspberry Pi. Use I2C interface, could be used for Robot applications.

FEATURES

  • Compatible with Raspberry Pi
  • I2C interface. Slave address hardware configurable makes your pi able to connect 32 motors at the same time
  • Integrate PCA9685, supports 12bits PWM output
  • Integrate TB6612FNG, high performance
  • Integrate 5V regulator, output current up to 3A.
  • Pins out I2C interface, could connect to other development board
  • Come with sample codes and user manual

SPECIFICATIONS

Operating voltage: 6V~12V (VIN port)
Logic voltage: 3.3V
PWM controller: PCA9685
Interface: I2C
Motor controller: TBA6612FNG
Dimension: 65mm x 30mm
Holes size: 3.0mm

INTERFACES

Example1.png] Example2.png]

PIN Description
5V 5V
3V3 3.3V
GND Ground
SDA I2C Data
SCL I2C Clock
VIN Driver voltage for motor(6-12V)
A1 positive pole of motor A
A2 negative pole of motor A
B1 positive pole of motor B
B2 negative pole of motor B

HARDWARES

The module includes three part in hardware: Power, PWM and Motor driver

POWER

Example3.png]
MP1854 regulator is used to convert the input voltage (VIN_USER), has wide 4.5V to 28V input range, could provide 3A output. Even the chip supports 28V input, however, VIN_USER is also the power supply for motor, so the actual working voltage of this module is 6-12V.
MP1854 outputs stable 5V, which is used to power Raspberry Pi, and supplies 3.3V logic level for PWM and motor driver via RT9193-33. Example4.png]

PWM

Raspberry Pi only has one hardware PWM pin (GPIO.1), and the software PWM of WiringPi and Python will cost CPU resources. This module, we use PCA9685, I2C bus controlled, support 16-channel 12-bits PWM output. The frequency range of PWM is 40Hz to 1000Hz.
It is very simply to use, to output PWM signal you only need to control corresponding registers value of chip. Example5.png]
Refer the recommend circuit, LED0-LED5 are motor control pins.
From Page6 to Page8 of datasheet:
Example6.png]
The slave address of I2C bus is 7-bits, highest is fixed 1. A5-A0 are hardware selectable.
This Motor Driver HAT, A5 is connected to ground (0) by default, you can change resistors of A0-A4 to configure the slave address. If you weld a resistor or short it, means 1, otherwise 0. The address range from 0x40 to 0x5F.
Example7.png]
For example:

  • A5 is 0, A0-A4 are disconnected (don’t weld), so they are 0 as well. The final I2Cslave address is 0x40
  • Welding 0Ω resistors to A0-A4 or shorting them, the final I2C slave address is 0x5F. You can use i2cdetect tool to detect i2C devices on Raspberry Pi as below: execute command: i2cdetect -y 1

Example8.png]

MOTOR DRIVER

Example9.png
TB6612FNG is a driver IC for DC motor with high performance.
VIN_USER is input voltage, in theory, motor speed up if this voltage is increased. Recommend input voltage is 6~12V.
PWMA and PWMB control speed of motors, AIN1 and AIN2, BIN1 and BIN2 control rotate direction of motors. A1 and A2, B1 and B2 are connect to positive/negative poles of two motors separately.

HOW TO USE

ENABLE I2C INTERFACE

To works with Raspberry Pi, you should first enable I2C interface as below:

sudo raspi-config

Then choose Interfacing Options -> I2C -> Yes
Example10.png
Example11.png
Example12.png
【Note】If you get errors information after running demo code, please modify the modules file as below:

sudo nano /etc/mdoules

Append these statements to the end and save:

i2c-dev
i2c-bcm2708

DOWNLOAD DEMO CODE

Demo code can be downloaded from Wiki:

Extract on your PC and copy to Raspberry Pi
Example13.png

LIBRARIES INSTALLATION

Before running the demo code, you should install necessary libraries (WiringPi, BCM2835 and python). About how to install libraries, you can refer to this page:

CODE ANALYSIS

We provide three demo codes for Raspberry Pi, which are based on BCM2835, WiringPi and python libraries separately. BCM2835


PROJECT DIRECTORY AND FILES
Example14.png

/bin:
    .o files generated by makefile
Makefile: makefile is used to tell the compiler how to compile your project/code.
motor: executable file, which you can execute to run the code
/Obj: workspace of project
    Debug.h: heard files of debug function, you can use DEBUG() to print debug information like printf() by change USE_DEBUG to 1
    DEV_Config.c(h): Defines PINS used and communication type, different between BCM2835 and WiringPi.
    PCA9685.c(h): Drive code of PCA9685 chip. Could output 16-channel PWM signal via I2C interface
    MotorDriver.c(.h): Drive code of TB6612FNG chip, control two motors. 
    main.c: main function

DEMO CODES

  • initialize BCM2835 libraries
if(DEV_ModuleInit())
   exit(0);
  • Initialize motor and PCA9685
Motor_Init();
  • Control motors
Motor_Run(MOTORA, FORWARD, 100);

Parameter 1: MOTORA or MOTORB
Parameter 2: FORWARD or BACKWARD
Parameter 3: 0~100
If you use this module to control robot, with this function you can control the whole motion of robot.
This project has Exception Handling. Generally, motor keeps moving even you stop
project. value of control register doesn’t be clean even you use CTRL+c to stop code.

signal(SIGINT, Handler);

single is signal handling function of linux system. SIGINT signal generates when CTRL+c is executed to stop process, then Handler() function will run. In this function, motors are stopped

Motor_Stop(MOTORA); 
Motor_Stop(MOTORB);
DEV_ModuleExit();
    exit(0);

USING

Demo code you download has no executable file moto, you need to run make to generate it then execute command ./motor to run the demo code.
If you modify or add any functions, you need to run make again to update
If you change values of heard files, command make clear is also need before make.
WIRINGPI


PROJECT DIRECTORY AND FILES

Example15.png
The files on WiringPi project directory are similar to BCM2835. Their only difference are:
DEV_Config.c(h): functions called are different
Makefile: linker is different.

USING

Demo code you download has no executable file moto, you need to run make to generate it then execute command ./motor to run the demo code.
If you modify or add any functions, you need to run make again to update

If you change values of heard files, command make clear is also need before make.

PYTHON


PROJECT DIRECTORY AND FILES



Example16.png
PCA9685.py is driver code, use I2C interface to output 16-channle PWM signals.
main.py: Motor driver code


DEMO CODE

  • Instantiate PCA9685 library
pwm = PCA9685(0x40, debug=True)

Parameter 1: slave address of PCA9685, hardware configurable
Parameter 2: enable/disable debug information

pwm.setPWMFreq(50)

Set PWM frequency in range 40~1000

  • Initialize motors
class MotorDriver(): 
   def init (self):
     self.PWMA = 0
     self.AIN1 = 1
     self.AIN2 = 2
     self.PWMB = 5
     self.BIN1 = 3
     self.BIN2 = 4 
Motor = MotorDriver()

Output PWM to channel 0~5

  • Control PWM
pwm.setDutycycle(self.PWMA, speed)

Parameter 1: output channel Parameter 2: Duty ratio, range 0~100

  • Control level
pwm.setLevel(self.AIN1, 1)

Parameter 1: output channel
Parameter 2: level, 1 is high and 0 is low

  • Control motor
Motor.MotorRun(0, 'forward', 0)

Parameter 1: 0 and 1, stands for two motor separately
Parameter 2: forward and backward
Parameter 3: integers in 0~100, control speed

MORE


You can also control it via Bluetooth or WiFi. About how to use you can refer to Servo Driver HAT:
https://www.waveshare.com/w/upload/1/1b/Servo_Driver_HAT_User_Manual_EN.pdf

Resources

Examples

Related Guides

FAQ

 Answer:
If the error is reported by the program, it may be a problem with the bcm library, try using the latest bcm library:
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.70.tar.gz
tar zxvf bcm2835-1.70.tar.gz 
cd bcm2835-1.70/
sudo ./configure
sudo make && sudo make check && sudo make install
# For more information, please refer to the official website: http://www.airspayce.com/mikem/bcm2835/
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Support

Support

If you require technical support, please go to the Support page and open a ticket.