Intermediate
30 min

Bring your creative vision to life with PCA9745B and STM32F091RC

Crafting colorful moments: RGBA LED control simplified!

LED Driver 16 Click with Nucleo-64 with STM32F091RC MCU

Published Feb 26, 2024

Click board™

LED Driver 16 Click

Dev. board

Nucleo-64 with STM32F091RC MCU

Compiler

NECTO Studio

MCU

STM32F091RC

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

Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin

headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is

provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.

Nucleo 64 with STM32F091RC MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

32768

You complete me!

Accessories

Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 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 STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Nucleo-64 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PC12
RST
SPI Chip Select
PB12
CS
SPI Clock
PB3
SCK
SPI Data OUT
PB4
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Output Enable
PC8
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

LED Driver 16 Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-64 accessories 1 image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F091RC MCU as your development board.

Click Shield for Nucleo-64 accessories 1 image hardware assembly
Nucleo 64 with STM32F401RE MCU front image hardware assembly
LTE IoT 5 Click front image hardware assembly
Prog-cut hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
Nucleo-64 with STM32XXX MCU Access MB 1 Mini B Conn - upright/background 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
Clicker 4 for STM32F4 HA MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step 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++;
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

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

Additional Support

Resources

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