Beginner
10 min

Upgrade project's visual impact with ring of red LEDs, SN74HC595 and PIC18F47K40

Ring of brilliance: Elevate your project with red LED magic!

Led ring R Click with Curiosity HPC

Published Nov 01, 2023

Click board™

Led ring R Click

Development board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18F47K40

Our solution featuring a ring of 32 red LEDs delivers a captivating and versatile lighting option for your projects, perfect for applications requiring attention-grabbing visuals and dynamic effects

A

A

Hardware Overview

How does it work?

LED ring R Click is based on four SN74HC595, an 8-bit serial-in, parallel-out 3-state shift register output latches from Texas Instruments. The SN74HC595s are connected in a daisy chain from one’s serial data output pin to another serial data input pin. Both the shift and storage registers have separate clocks. The data in the shift register is transferred to the storage register on a LOW-to-HIGH transition of the LAT pin. If both clocks are logic state timed together, the shift register will always be one clock pulse ahead of the storage

register. Data in the storage register appears at the output whenever the output enable pin (OE) is LOW (in this case, always since the OE pin is connected to GND and is always low). The LED Ring R Click uses an SPI serial interface to communicate with the host MCU via the mikroBUS™ socket. The CLK pin serves as a shift register clock input, while the LAT pin serves as a storage register clock input for all four SN74HC595. The MR pin is a master reset pin with active LOW and will reset all four SN74HC595 shift registers at

once. All four SN74HC595 outputs are enabled by default, as they are pulled down, and the enabling feature on this Click board™ is not given to the user. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the 3.3V 5V jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the 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 ring R Click top side image
LED ring R Click bottom side image

Features overview

Development board

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Curiosity HPC double image

Microcontroller Overview

MCU Card / MCU

PIC18F47K40

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3728

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Master Reset
RD0
RST
Latch Signal
RA3
CS
SPI Clock
RB1
SCK
SPI Data OUT
RB2
MISO
SPI Data IN
RB3
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
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

Schematic

Led ring R Click Schematic schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.

Curiosity HPC front no-mcu image hardware assembly
Thermo 28 Click front image hardware assembly
MCU DIP 40 hardware assembly
Prog-cut hardware assembly
Curiosity HPC MB 1 - upright/with-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
Necto DIP image step 7 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for LED ring R Click driver.

Key functions:

  • ledringr_write_data - Generic write function

  • ledringr_turn_on_led - Turn On LED by position

  • ledringr_led_ring_set - Set led

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 LedringR Click example
 * 
 * # Description
 * LED ring  R click is a mikroBUS™ add-on board with a ring of 32 red LEDs driven.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes SPI driver and performs device configuration.
 * 
 * ## Application Task  
 * Show functionality of Led_Ring_R Click, rotating and turn on/off led's, using the SPI interface.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "ledringr.h"

// ------------------------------------------------------------------ VARIABLES

static ledringr_t ledringr;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    ledringr_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.

    ledringr_cfg_setup( &cfg );
    LEDRINGR_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    ledringr_init( &ledringr, &cfg );
}

void application_task ( void )
{
    uint32_t ring_led_on = 0x00000001;
    uint8_t ring_led_counter;
    uint8_t number_led;

    ledringr_led_ring_set( &ledringr );

    for ( ring_led_counter = 32; ring_led_counter > 0; ring_led_counter--)
    {
        ledringr_turn_on_led( &ledringr, ring_led_counter );
        Delay_100ms( );
    }

    Delay_100ms( );

    while ( ring_led_on < 0xFFFFFFFF )
    {
        ledringr_write_data( &ledringr, ring_led_on );
        ring_led_on = ring_led_on | (ring_led_on << 1);
        Delay_100ms( );
    }
    ledringr_write_data( &ledringr, ring_led_on );

    while ( ring_led_on > 0x00000001 )
    {
        ledringr_write_data( &ledringr, ring_led_on );
        ring_led_on = ring_led_on >> 1;
        Delay_100ms( );
    }
    ledringr_write_data( &ledringr, ring_led_on );

    Delay_100ms( );

    ring_led_on = 0x11111111;
    for ( ring_led_counter = 0; ring_led_counter < 32; ring_led_counter++ )
    {
        ledringr_write_data( &ledringr, ring_led_on );

        ring_led_on *= 2;

        if ( ring_led_on == 0x88888888 )
        {
            ring_led_on = 0x11111111;
        }
            
        Delay_100ms( );
    }
    
    for ( ring_led_counter = 0; ring_led_counter < 16; ring_led_counter++ )
    {
        ledringr_write_data( &ledringr, 0xAAAAAAAA );
        Delay_100ms( );
        
        ledringr_write_data( &ledringr, 0x55555555 );
        Delay_100ms( );
    }

    ledringr_led_ring_reset( &ledringr );

    Delay_1sec( );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources