Beginner
10 min

Customize and control your lighting with LT3755 and PIC18F4685

Smart choice for modern lighting applications

LED Driver 17 Click with EasyPIC v7a

Published Nov 01, 2023

Click board™

LED Driver 17 Click

Development board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18F4685

With our LED driver solution, you can count on uninterrupted, reliable performance, guaranteeing that your lighting systems are always on when needed.

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Hardware Overview

How does it work?

LED Driver 17 Click is based on the LT3755, a highly efficient DC/DC controller from Analog Devices. This Click board™ is designed as a Buck mode LED driver with the ability to output 500mA, offering, in addition, PWM dimming functionality. The LTR3755, a highly efficient DC/DC controller, operates as a constant-current source and features onboard low-side external N-channel power MOSFETs, which are driven from an internal regulated supply and are capable of driving high-power 16V LEDs. Due to its high efficiency and reliable protection features, this board can be used in applications that require consistent and precise LED lighting control. It can also be used in applications that demand high power output,

such as commercial and industrial lighting. In terms of connectivity, this solution is designed to be controlled via the PWM pin of the mikroBUS™ socket to provide LED dimming control with ratios of up to 3000:1. In addition, the LT3755 also has a frequency adjust pin that allows the user to program the switching frequency from 100kHz to 1MHz. This feature is performed via an onboard R5 resistor, with the 800kHz set as the default value to optimize efficiency and performance. Other than the PWM pin, this Click board™ also features a fault pin labeled FLT, which is routed to the default interrupt INT position of the mikroBUS™ socket. This fault pin indicates any fault conditions to an external system, including overvoltage and

overcurrent protection. Besides information via the mikroBUS™ socket, the fault signal is visually indicated via a red LED labeled LD2. This LED Driver 17 Click supports an external power supply for the driver, which can be connected to the input terminal labeled VIN and should be within the range of 22V to 36V. 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 17 Click hardware overview image

Features overview

Development board

EasyPIC v7a is the seventh generation of PIC development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. 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, EasyPIC v7a allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC v7a development board

contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) 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. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7a 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.

EasyPIC v7a double side image

Microcontroller Overview

MCU Card / MCU

PIC18F4685

Architecture

PIC

MCU Memory (KB)

96

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3328

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
PWM Input
RC0
PWM
Fault Interrupt
RB0
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

Schematic

LED Driver 17 Click Schematic schematic

Step by step

Project assembly

EasyPIC v7a front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7a as your development board.

EasyPIC v7a front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyPIC v7a Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

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.

UART Application Output Step 1

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.

UART Application Output Step 2

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".

UART Application Output Step 3

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.

UART Application Output Step 4

Software Support

Library Description

This library contains API for LED Driver 17 Click driver.

Key functions:

  • leddriver17_get_fault_pin - This function returns the fault (FLT) pin logic state.

  • leddriver17_set_duty_cycle - This function sets the PWM duty cycle in percentages ( Range[ 0..1 ] ).

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 main.c
 * @brief LED Driver 17 Click example
 *
 * # Description
 * This example demonstrates the use of LED Driver 17 click board by changing
 * the LEDs dimming level.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 *
 * ## Application Task
 * Changes the LEDs dimming level by setting the PWM duty cycle every 500ms. 
 * The duty cycle percentage will be displayed on the USB UART. It also checks
 * the fault indication pin and displays it accordingly.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "leddriver17.h"

static leddriver17_t leddriver17;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    leddriver17_cfg_t leddriver17_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.
    leddriver17_cfg_setup( &leddriver17_cfg );
    LEDDRIVER17_MAP_MIKROBUS( leddriver17_cfg, MIKROBUS_1 );
    if ( PWM_ERROR == leddriver17_init( &leddriver17, &leddriver17_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( LEDDRIVER17_ERROR == leddriver17_default_cfg ( &leddriver17 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    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;
    
    if ( !leddriver17_get_fault_pin ( &leddriver17 ) )
    {
        log_printf( &logger, " Fault detected!\r\n" );
    }
    leddriver17_set_duty_cycle ( &leddriver17, duty );
    log_printf( &logger, " Duty: %u%%\r\n\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

Additional Support

Resources