Intermediate
30 min

Bring your creative vision to life with PCA9745B and STM32F302VC

Crafting colorful moments: RGBA LED control simplified!

LED Driver 16 Click with CLICKER 4 for STM32F302VCT6

Published Jul 22, 2025

Click board™

LED Driver 16 Click

Dev. board

CLICKER 4 for STM32F302VCT6

Compiler

NECTO Studio

MCU

STM32F302VC

Our cutting-edge LED driver solution offers simplified control for dimming and blinking RGBA LEDs, allowing you to create dynamic lighting effects effortlessly and customize your ambiance

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Hardware Overview

How does it work?

LED Driver 16 Click is based on the PCA9745B, a daisy-chain SPI-compatible 16-channel constant current LED driver from NXP Semiconductors. The PCA9745B provides a maximum output current of 57mA per channel (set through an onboard R6 resistor), making it suitable for dimming and blinking Red/Green/Blue/Amber (RGBA) LEDs. Each of the 16 LED outputs has its 8-bit resolution (256 steps) fixed-frequency individual PWM controller, operating at 31.25 kHz with an adjustable duty cycle. The duty cycle goes from 0% to 100%, allowing LEDs to be set to a specific brightness value; either dim or blink all LEDs with the same value. Gradation control for all current sources is achieved through serial interface and 8-bit DACs, allowing users to ramp current automatically, without MCU intervention, and thus

adjust brightness levels for each LED current source. There are four selectable gradation control groups, and each group has independently four registers to control ramp-up and ramp-down rate, step time, hold ON/OFF time, and final hold ON output current. Two gradation operation modes are available for each group: single shot mode (output pattern once) and continuous mode (output pattern repeat). LED Driver 16 Click communicates with MCU through a register-selectable standard SPI interface that enables high clock speed up to 25MHz for optimum performance, supporting the most common SPI mode, SPI Mode 0. In addition to the SPI interface signals, this board uses several other signals from the mikroBUS™ socket. The reset pin routed on the RST pin of the mikroBUS™ socket provides the

general reset ability, while the OE pin of the mikroBUS™ socket, hence, offers a switch operation (enabled/disabled) to turn ON/OFF power delivery to the PCA9745B. The OE pin can also be used as an external dimming control signal. In that case, the external clock frequency must be very high, more precisely unseen by the human eye, and the duty cycle value determines the brightness of the LEDs. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can 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.

LED Driver 16 Click top side image
LED Driver 16 Click bottom side image

Features overview

Development board

Clicker 4 for STM32F3 is a compact development board designed as a complete solution, you can use it to quickly build your own gadgets with unique functionalities. Featuring a STM32F302VCT6, four mikroBUS™ sockets for Click boards™ connectivity, power managment, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core, there is a STM32F302VCT6 MCU, a powerful microcontroller by STMicroelectronics, based on the high-

performance Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the development

board much simpler and thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution which can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws. For most applications, a nice stylish casing is all that is needed to turn the Clicker 4 development board into a fully functional, custom design.

CLICKER 4 for STM32F302VCT6 double image

Microcontroller Overview

MCU Card / MCU

STM32F302VC Image

Architecture

ARM Cortex-M4

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

40960

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PC15
RST
SPI Chip Select
PA4
CS
SPI Clock
PA5
SCK
SPI Data OUT
PA6
MISO
SPI Data IN
PA7
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Output Enable
PE9
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
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Take a closer look

Click board™ Schematic

LED Driver 16 Click Schematic schematic

Step by step

Project assembly

PIC32MZ MXS Data Capture Board front image hardware assembly

Start by selecting your development board and Click board™. Begin with the CLICKER 4 for STM32F302VCT6 as your development board.

PIC32MZ MXS Data Capture Board front image hardware assembly
Thermo 21 Click front image hardware assembly
Thermo 21 Click complete accessories setup image hardware assembly
Board mapper by product6 hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC32MZ MXS Data Capture Board NECTO MCU Selection Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto image step 11 hardware assembly

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 LED Driver 16 Click driver.

Key functions:

  • leddriver16_set_led_state - This function sets the output state for the specified LEDs

  • leddriver16_set_led_pwm - This function sets the PWM duty cycle for the specified LEDs

  • leddriver16_set_led_iref - This function sets the gain settings for output current for the specified LEDs

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 main.c
 * @brief LED Driver 16 Click example
 *
 * # Description
 * This example demonstrates the use of LED Driver 16 Click board by performing
 * 3 different types of LED control (LED PWM dimming, LED blinking, and LED curtain).
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the Click default configuration.
 *
 * ## Application Task
 * Performs 3 different types of LED control examples. Each example repeats 5 times before
 * switching to another. The name of the currently set example will be displayed on the USB UART accordingly.
 * - Example 1:
 * LED PWM dimming - starts with min PWM duty cycle and increases it to max, then decreases
 * it to min duty cycle in a loop with a 5ms delay on duty change.
 * - Example 2:
 * LED blinking - toggles all LEDs state from ON to OFF and vice-versa with a 500ms delay in between.
 * - Example 3:
 * LED curtain - turns ON the LEDs one by one from LED0 to LED15 with a 100ms delay on transition
 * to the next LED.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "leddriver16.h"

static leddriver16_t leddriver16;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    leddriver16_cfg_t leddriver16_cfg;  /**< Click config object. */

    /** 
     * 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.
    leddriver16_cfg_setup( &leddriver16_cfg );
    LEDDRIVER16_MAP_MIKROBUS( leddriver16_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == leddriver16_init( &leddriver16, &leddriver16_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( LEDDRIVER16_ERROR == leddriver16_default_cfg ( &leddriver16 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    static uint8_t example_repeat_num = 5;
    uint8_t repeat_cnt = 0;
    log_printf( &logger, " LED PWM dimming\r\n\n" );
    leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, LEDDRIVER16_LEDOUT_PWM_ALL );
    while ( repeat_cnt < example_repeat_num )
    {
        uint8_t pwm_duty = LEDDRIVER16_PWM_DUTY_MIN;
        while ( pwm_duty < LEDDRIVER16_PWM_DUTY_MAX )
        {
            leddriver16_set_led_pwm ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, pwm_duty );
            Delay_ms ( 5 );
            pwm_duty++;
        }
        while ( pwm_duty > LEDDRIVER16_PWM_DUTY_MIN )
        {
            leddriver16_set_led_pwm ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, pwm_duty );
            Delay_ms ( 5 );
            pwm_duty--;
        }
        Delay_ms ( 100 );
        repeat_cnt++;
    }
    
    log_printf( &logger, " LED blinking\r\n\n" );
    repeat_cnt = 0;
    leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, LEDDRIVER16_LEDOUT_OFF );
    while ( repeat_cnt < example_repeat_num )
    {
        leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, LEDDRIVER16_LEDOUT_ON );
        Delay_ms ( 500 );
        leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, LEDDRIVER16_LEDOUT_OFF );
        Delay_ms ( 500 );
        repeat_cnt++;
    }
    
    log_printf( &logger, " LED curtain\r\n\n" );
    repeat_cnt = 0;
    leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_ALL, LEDDRIVER16_LEDOUT_OFF );
    while ( repeat_cnt < example_repeat_num )
    {
        uint8_t led_cnt = 0;
        while ( led_cnt < 16 )
        {
            leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_0 << led_cnt, LEDDRIVER16_LEDOUT_ON );
            Delay_ms ( 100 );
            leddriver16_set_led_state ( &leddriver16, LEDDRIVER16_LED_CHANNEL_0 << led_cnt, LEDDRIVER16_LEDOUT_OFF );
            led_cnt++;
        }
        Delay_ms ( 500 );
        repeat_cnt++;
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END

Additional Support

Resources

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