Master motor speed control with Si8711CC and ATmega644P
PWM precision meets motor control
Published Jul 20, 2023
Click board™
PWM driver Click
Dev Board
EasyAVR v7
Compiler
NECTO Studio
MCU
ATmega644P
Unlock speed control possibilities with our PWM-controlled DC motor solution
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Hardware Overview
How does it work?
PWM driver Click is based on the Si8711CC, a 5kV LED emulator input, open collector output isolator from Skyworks. Compared to the optocouplers, the Si8711CC is more resistant to temperature, age, and forward current effects. It has a longer service life, higher common-mode transient immunity, and more. The Si8711CC is based on proprietary CMOS isolation technology for low-power, high-speed operation and is resistant to wear-out effects that, in the case of optocouplers, degrade the performance. The Si8711CC features up to 5000VRMS isolation and 10kV surge protection, making it a perfect isolator. For controlling the devices, it is capable of data rates DC of up to 15Mbps, with a propagation delay of 30ns. The Si8711CC controls the loads over the DMP3010LK3,
a P-channel enhancement mode MOSFET from Diodes Incorporated. This fast-switching diode has ESD protected gate, low input capacitance, and low on-resistance, designed to maintain superior switching performance, making it ideal for high-efficiency power management applications. The PWM Driver Click comes with the screw terminals labeled LOAD (+END, -END) to connect the load, which the Si7811CC controls over the DMP3010LK3 diode, and EXT for external power supply. It is not recommended to use this Click board™ with loads over 50W as the MOSFET can get overheated; this, however, does not apply if the Click board™ is used as an ON/OFF switch. The PWM Driver Click is controlled by the host MCU by PWM pulses over the PWM pin of the mikroBUS™ socket. The PWM
pin does not have direct control over the Si8711CC but rather through the DMG3420U, an N-channel enhancement mode MOSFET from Diodes Incorporated. This diode shares many features with the one mentioned above, such as low on-resistance, low input capacitance, fast switching speed, and more. This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more
efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)
connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.
Track your results in real time
Application Output
After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.
Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.
In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".
The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
Software Support
Library Description
This library contains API for PWM driver Click driver.
Key functions:
pwmdriver_set_duty_cycle- Generic sets PWM duty cyclepwmdriver_pwm_stop- Stop PWM modulepwmdriver_pwm_start- Start PWM module
Open Source
Code example
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* @file
* @brief PwmDriver Click example
*
* # Description
* This application is controls the speed DC motors.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization driver enables - GPIO, PWM initialization set PWM duty cycle and PWM frequency,
* start PWM, enable the engine, and start to write log.
*
* ## Application Task
* This is an example that demonstrates the use of the PWM driver Click board.
* This example shows the automatic control of PWM,
* the first increases duty cycle and then the duty cycle is falling.
* Results are being sent to the Usart Terminal where you can track their changes.
*
* *note:*
* EXT PWR 3-30VDC
*
* @author Nikola Peric
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "pwmdriver.h"
// ------------------------------------------------------------------ VARIABLES
static pwmdriver_t pwmdriver;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
pwmdriver_cfg_t cfg;
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, "---- Application Init ----" );
// Click initialization.
pwmdriver_cfg_setup( &cfg );
PWMDRIVER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
pwmdriver_init( &pwmdriver, &cfg );
Delay_ms( 100 );
log_printf( &logger, " Initialization PWM \r\n " );
pwmdriver_set_duty_cycle( &pwmdriver, 0.0 );
pwmdriver_pwm_start( &pwmdriver );
Delay_ms( 1000 );
log_info( &logger, "---- Application Task ----" );
}
void application_task ( void )
{
static int8_t duty_cnt = 1;
static int8_t duty_inc = 1;
float duty = duty_cnt / 10.0;
pwmdriver_set_duty_cycle ( &pwmdriver, duty );
log_printf( &logger, "Duty: %d%%\r\n", ( uint16_t )( duty_cnt * 10 ) );
Delay_ms( 500 );
if ( 10 == duty_cnt )
{
duty_inc = -1;
}
else if ( 0 == duty_cnt )
{
duty_inc = 1;
}
duty_cnt += duty_inc;
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
