Beginner
10 min

Control things like volume or brightness and visually see those adjustments with TLC5925 and PIC18F97J94

Rotary knob with an illuminating ring that shows adjustment levels visually

Rotary R 2 Click with CLICKER 4 for PIC18F

Published Feb 28, 2024

Click board™

Rotary R 2 Click

Development board

CLICKER 4 for PIC18F

Compiler

NECTO Studio

MCU

PIC18F97J94

Ideal for precise user input, such as audio equipment (volume controls), lighting controls (intensity adjustment), or any application where a selection or setting needs to be adjusted accurately

A

A

Hardware Overview

How does it work?

Rotary R 2 Click is based on the TLC5925, a low-power 16-channel constant-current LED sink driver from Texas Instruments that, combined with a high-quality rotary encoder from ALPS, the EC12D1564402, allows you to add a precision input knob to your design. The EC12D1564402 incremental rotary encoder is surrounded by a ring of 16 red LEDs where a single rotation is divided into 15 discrete steps (in contrast to a potentiometer, a rotary encoder can be spun around continuously). The driver can control each LED individually, allowing various lighting effects to be programmed. The encoder outputs A and B signals (out of phase to each other) on the two mikroBUS™ lines, alongside the knob push-button

feature, which outputs through the interrupt line. The EC12D1564402 is a 15-pulse incremental rotary encoder with a push button. This encoder has unique mechanical specifications (debouncing time for its internal switches goes down to 2ms), and it can withstand a huge number of switching cycles, up to 30.000. The supporting debouncing circuitry allows contacts to settle before the output is triggered fully. Rotary R 2 Click uses a standard 4-wire SPI serial interface of the TLC5925 LED driver to communicate with the host MCU supporting clock frequency of up to 30MHz. Rotating the encoder, it outputs A and B signals (out of phase to each other) on the two mikroBUS™ lines, ENA and ENB pins of the

mikroBUS™ socket, alongside the push-button contact, which outputs through the SW pin (interrupt line) of the mikroBUS™ socket. Two SN74LVC1T45 single-bit bus transceivers from Texas Instruments are used for logic-level translation. 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.

Rotary R 2 Click hardware overview image

Features overview

Development board

Clicker 4 for PIC18F is a compact development board designed as a complete solution to build your own gadgets with unique functionalities quickly. It features a PIC18F97J94MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, and it is a perfect solution for the rapid development of many different types of applications. At its core is an 8-bit PIC18F97J94 MCU, a powerful microcontroller produced by Microchip, based on the high-performance CPU with two external clock modes, up to 64MHz. 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 that 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 PIC18F double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

3862

Used MCU Pins

mikroBUS™ mapper

Encoder Output B
PA5
AN
ID SEL
PJ4
RST
SPI Select / ID COMM
PL1
CS
SPI Clock
PD6
SCK
SPI Data OUT
PD5
MISO
SPI Data IN
PD4
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Encoder Output A
PG4
PWM
Switch Output
PB0
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

Rotary R 2 Click Schematic schematic

Step by step

Project assembly

Clicker 4 for STM32F4 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the CLICKER 4 for PIC18F as your development board.

Clicker 4 for STM32F4 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
Clicker 4 STM32F4 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 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

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 Rotary R 2 Click driver.

Key functions:

  • rotaryr2_set_led_pos - This function turns on the LED for the selected LED position

  • rotaryr2_set_led_data - This function, using SPI serial interface, writes a desired 16-bit data

  • rotaryr2_get_state_switch - This function return rotary encoder switch signal, states of the SW(INT)

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 Rotary R 2 Click example
 *
 * # Description
 * This library contains the API for the Rotary R 2 Click driver 
 * to control LEDs states and a rotary encoder position readings.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of SPI module and log UART.
 * After the driver init, the app executes a default configuration and turn off all LEDs.
 *
 * ## Application Task
 * This example demonstrates the use of the Rotary R 2 Click board.
 * The demo example shows the functionality of a rotary encoder used to control LEDs.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rotaryr2.h"

#define ROTARYR2_ONE_LED          ROTARYR2_SET_LED_DATA_1
#define ROTARYR2_TWO_LED          ROTARYR2_SET_LED_DATA_1  | ROTARYR2_SET_LED_DATA_9
#define ROTARYR2_FOUR_LED         ROTARYR2_SET_LED_DATA_1  | ROTARYR2_SET_LED_DATA_5  | \
                                  ROTARYR2_SET_LED_DATA_9  | ROTARYR2_SET_LED_DATA_13 
#define ROTARYR2_EIGHT_LED        ROTARYR2_SET_LED_DATA_1  | ROTARYR2_SET_LED_DATA_3  | \
                                  ROTARYR2_SET_LED_DATA_5  | ROTARYR2_SET_LED_DATA_7  | \
                                  ROTARYR2_SET_LED_DATA_9  | ROTARYR2_SET_LED_DATA_11 | \
                                  ROTARYR2_SET_LED_DATA_13 | ROTARYR2_SET_LED_DATA_15
#define ROTARYR2_EIGHT_LED_INV    ROTARYR2_SET_LED_DATA_2  | ROTARYR2_SET_LED_DATA_4  | \
                                  ROTARYR2_SET_LED_DATA_6  | ROTARYR2_SET_LED_DATA_8  | \
                                  ROTARYR2_SET_LED_DATA_10 | ROTARYR2_SET_LED_DATA_12 | \
                                  ROTARYR2_SET_LED_DATA_14 | ROTARYR2_SET_LED_DATA_16

static rotaryr2_t rotaryr2;
static log_t logger;

static uint8_t start_rot_status = 0;
static uint8_t led_demo_state = 0;
static uint8_t old_state = 0;
static uint8_t new_state = 1;
static uint8_t old_rot_state = 0;
static uint8_t new_rot_state = 1;
static uint16_t led_data = 1;

/**
 * @brief Rotary R 2 select LED demo data function.
 * @details This function selects one of the four LED demo data 
 * based on the current state of the LED demo.
 * @return LED demo data:
 *         @li @c 0x0001 (ROTARYR2_ONE_LED)   - Turn ON LED[1],
 *         @li @c 0x0101 (ROTARYR2_TWO_LED)   - Turn ON LED[1,9],
 *         @li @c 0x0101 (ROTARYR2_FOUR_LED)  - Turn ON LED[1,5,9,13],
 *         @li @c 0x5555 (ROTARYR2_EIGHT_LED) - Turn ON LED[1,3,5,7,9,11,13,15].
 */
static uint16_t rotaryr2_sel_led_demo_data ( uint8_t led_demo_state );

/**
 * @brief Rotary R 2 switch detection function.
 * @details This function is used for the switch state detection.
 * @return Nothing.
 */
static void rotaryr2_switch_detection ( void );

/**
 * @brief Rotary R 2 encoder mechanism function.
 * @details This function is used to control the state of the LEDs 
 * by detecting the rotation direction of the rotary encoder.
 * @return Nothing.
 */
static void rotaryr2_encoder_mechanism ( void );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rotaryr2_cfg_t rotaryr2_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.
    rotaryr2_cfg_setup( &rotaryr2_cfg );
    ROTARYR2_MAP_MIKROBUS( rotaryr2_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == rotaryr2_init( &rotaryr2, &rotaryr2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( ROTARYR2_ERROR == rotaryr2_default_cfg ( &rotaryr2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    if ( ROTARYR2_OK == rotaryr2_set_led_data( &rotaryr2, led_data ) )
    {
        rotaryr2_switch_detection( );
        rotaryr2_encoder_mechanism( );
    }
}

int main ( void ) 
{
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

static uint16_t rotaryr2_sel_led_demo_data ( uint8_t led_demo_state ) 
{
    switch ( led_demo_state ) 
    {
        case 0: 
        {
            return ROTARYR2_ONE_LED;
            break;
        }
        case 1: 
        {
            return ROTARYR2_TWO_LED;
            break;
        }
        case 2: 
        {
            return ROTARYR2_FOUR_LED;
            break;
        }
        case 3: 
        {
            return ROTARYR2_EIGHT_LED;
            break;
        }
        default: 
        {
            return ROTARYR2_ONE_LED;
            break;
        }
    }
}

static void rotaryr2_switch_detection ( void )
{
    if ( rotaryr2_get_state_switch( &rotaryr2 ) ) 
    {
        new_state = 1;
        if ( (  1 == new_state ) && ( 0 == old_state ) ) 
        {
            old_state = 1;
            led_demo_state = ( led_demo_state + 1 ) % 5;
            if ( 4 == led_demo_state ) 
            {
                for ( uint8_t n_cnt = 0; n_cnt < 10; n_cnt++ )
                {
                    rotaryr2_set_led_data( &rotaryr2, ROTARYR2_EIGHT_LED_INV );
                    Delay_ms( 100 );
                    rotaryr2_set_led_data( &rotaryr2, ROTARYR2_EIGHT_LED );
                    Delay_ms( 100 );
                }
                
                for ( uint8_t led_p = ROTARYR2_SET_LED_POS_1; led_p <= ROTARYR2_SET_LED_POS_16; led_p++ ) 
                {
                    rotaryr2_set_led_pos( &rotaryr2, led_p );
                    Delay_ms( 100 );
                }
                
                led_demo_state = 0;
                led_data = rotaryr2_sel_led_demo_data( led_demo_state );
            }
            else 
            {
                led_data = rotaryr2_sel_led_demo_data( led_demo_state );
            }
        }
    }
    else 
    {
        old_state = 0;
    }
}

static void rotaryr2_encoder_mechanism ( void )
{
    if ( rotaryr2_get_state_ena( &rotaryr2 ) == rotaryr2_get_state_enb( &rotaryr2 ) ) 
    {
        old_rot_state = 0;
        start_rot_status = rotaryr2_get_state_ena( &rotaryr2 ) && rotaryr2_get_state_enb( &rotaryr2 );
    }
    else 
    {
        new_rot_state = 1;
        if ( new_rot_state != old_rot_state ) 
        {
            old_rot_state = 1;
            if ( start_rot_status != rotaryr2_get_state_ena( &rotaryr2 ) ) 
            {
                led_data = ( led_data << 1 ) | ( led_data >> 15 );
            }
            else 
            {
                led_data = ( led_data >> 1 ) | ( led_data << 15 );
            }
        }
    }
}

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

Additional Support

Resources