Experience limitless PWM possibilities with PCA9685 and ATmega328
16 channels, 1 interface - Total PWM dominance
Published Feb 14, 2024
Click board™
PWM Click
Dev. board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328
This innovative solution offers seamless control of 16 PWM outputs through a single I2C interface, providing users with unmatched precision and versatility in managing their devices and applications
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Hardware Overview
How does it work?
PWM Click is based on the PCA9685, a fully programmable 16-channel PWM controller from NXP Semiconductors. Each output channel has a 12-bit resolution (4096 steps) fixed frequency individual PWM controller that operates at a programmable frequency from a typical 24Hz to 1526Hz with a duty cycle that is adjustable from 0% to 100%. All channels are set to the same PWM frequency. Although it is targeted toward driving LEDs, this Click board™ can also be used for other purposes, such as motor and industrial control, robotics, and similar applications that can benefit from having a compact 16-channel PWM driver. Each output channel can be turned OFF or ON, with no PWM control, or set at its individual PWM controller value, which minimizes current surges. The ON and OFF time delay is independently programmable for each of the 16 channels. The
output channels are programmed to be either open-drain with a 25mA current sink or totem poles with a 25mA sink and 10mA source capability at 5V. PWM Click communicates with an MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Fast Mode Plus up to 1MHz. It also has a 7-bit slave address with the first four MSBs fixed to 1000. The slave address pins, A0, A1, and A2, are programmed by the user and determine the value of the three LSBs of the slave address. The value of these address pins can be set by positioning onboard SMD jumpers labeled as I2C ADR to an appropriate position marked as 0 or 1. It also possesses an additional enable signal, routed on the RST pin of the mikroBUS™ socket labeled EN, allowing asynchronous control of the output channels. It can also be used to set all the outputs
to a defined I2C- programmable logic state or externally ‘pulse width modulate’ the outputs. It is useful when software control requires multiple devices to be dimmed or blinked together. In addition, this Click board™ has two unpopulated headers through which up to seven additional PWM Click boards™ can be connected together. With the help of I2C ADR jumpers, it is possible to specify a different I2C address for each board, allowing 112 PWM outputs on a single I2C line. This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the PWR SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
32
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for PWM Click driver.
Key functions:
pwm_dev_config- Device configuration function.pwm_set_channel_raw- Set channel raw function.pwm_set_all_raw- Set all channels raw function.
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* \file
* \brief PWM Click example
*
* # Description
* This is an example that shows the capability of PWM click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initalizes I2C driver, enables output, configures device, sets prescaling,
* configures output and makes an initial log.
*
* ## Application Task
* Changes the duty cycle of all channels every 10 seconds.
* All data are being logged on USB UART where you can track their changes.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "pwm.h"
// ------------------------------------------------------------------ VARIABLES
static pwm_t pwm;
static log_t logger;
static uint8_t config0[ 6 ] = { 1, 0, 0, 0, 1, 0 };
static uint8_t config1[ 6 ] = { 1, 0, 0, 0, 0, 1 };
static uint8_t config2[ 4 ] = { 0, 1, 0, 0 };
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
pwm_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.
pwm_cfg_setup( &cfg );
PWM_MAP_MIKROBUS( cfg, MIKROBUS_1 );
pwm_init( &pwm, &cfg );
Delay_ms( 100 );
pwm_set_output( &pwm, PWM_ENABLE );
pwm_dev_config( &pwm, &config0 );
pwm_set_pre_scale( &pwm, 0x04 );
pwm_dev_config( &pwm, &config1 );
pwm_output_config( &pwm, &config2 );
Delay_ms( 100 );
log_printf( &logger, "--------------------------\r\n" );
log_printf( &logger, " PWM Click \r\n" );
log_printf( &logger, "--------------------------\r\n" );
}
void application_task ( void )
{
uint8_t chann_id;
pwm_set_all_raw( &pwm, PWM_MAX_RESOLUTION / 2 );
log_printf( &logger, "All Channels set to 50%% duty cycle \r\n" );
log_printf( &logger, "--------------------------\r\n" );
Delay_ms( 10000 );
for ( chann_id = 0; chann_id < 8; chann_id++ )
{
pwm_set_channel_raw( &pwm, chann_id, 0, PWM_MAX_RESOLUTION / 4 );
}
log_printf( &logger, "Channels 0-7 set to 25%% duty cycle \r\n" );
log_printf( &logger, "--------------------------\r\n" );
Delay_ms( 10000 );
for ( chann_id = 0; chann_id < 8; chann_id++ )
{
pwm_set_channel_raw( &pwm, chann_id, 0, ( PWM_MAX_RESOLUTION / 4 ) * 3 );
}
log_printf( &logger, "Channels 0-7 set to 75%% duty cycle \r\n" );
log_printf( &logger, "--------------------------\r\n" );
Delay_ms( 10000 );
pwm_all_chann_state( &pwm, 0 );
log_printf( &logger, "All Channels disabled \r\n " );
log_printf( &logger, "--------------------------\r\n" );
Delay_ms( 5000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
