Intermediate
20 min

Experience smooth servo motor movements using TLC59401 and PIC18F57Q43

Precise 16-channel servo motor control solution for robotics and automation

Servo 2 Click with Curiosity Nano with PIC18F57Q43

Published Jul 02, 2025

Click board™

Servo 2 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Control up to 16 servo motors with high-resolution PWM and robust safety features perfect for robotics and automation systems

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Hardware Overview

How does it work?

Servo 2 Click is based on the TLC59401, a 16-channel LED driver from Texas Instruments designed to control multiple outputs using a high-precision constant-current sink architecture. Each of the 16 channels features an individually programmable 12-bit grayscale PWM control, allowing for 4096 levels of pulse width adjustment per output. This level of control is accessible via a serial interface, ensuring flexible and accurate operation across all channels. The maximum output current for each channel is defined by a single external resistor, which simplifies configuration. On the Servo 2 Click, this resistor is set to 330Ω (R7), resulting in a maximum current of approximately 120mA per channel. This makes the board well-suited not only for precise servo motor control but also for driving high-current LEDs in secondary applications, including monocolor, multicolor, and

full-color LED displays, signboards, and back lighting systems where accurate brightness control and current regulation are essential. This Click board™ establishes communication with the host MCU via a 4-wire SPI interface with a maximum clock frequency of 30MHz, ensuring reliable and high-speed data transfer. Beyond the SPI pins, the board includes additional control and status lines that enhance its functionality. The BLK pin is used to blank all outputs simultaneously - when set HIGH, all output channels are disabled and the internal grayscale counter is reset. When driven LOW, the outputs resume operation under the control of the internal PWM grayscale engine. The design also supports the parallel configuration of multiple output channels to increase total current-driving capability. The supply voltage for the connected loads is provided through the VEXT

terminal, which distributes the same voltage to all output channels. This voltage can go up to a maximum of 17V, making the board compatible with a wide range of connected devices, including servo motors and LEDs. Additionally, the ERR pin provides essential fault indication through two integrated monitoring features: LED open detection (LOD), which flags disconnected or broken LEDs, and the thermal error flag (TEF), which signals an over-temperature condition. 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.

Servo 2 Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

SG90 Digital Servo Motor from TowerPro is a compact and lightweight 9g servo, widely recognized for its balance of performance, reliability, and affordability. As an enhanced digital version of the original analog SG90, this servo offers improved precision and response, making it a popular choice for hobbyists and professionals alike. With a stall torque of 1.8kg/cm at 4.8V and an impressive operating speed of 0.1 seconds per 60 degrees, the SG90 is well-suited for applications requiring fast and accurate motion control. It features a durable POM (polyoxymethylene) gear set that ensures smooth operation and extended lifespan under moderate loads. Operating at 4.8V, the SG90 covers a temperature range from 0°C to 55°C, allowing reliable performance in various indoor and semi-controlled environments. Its tight dead band width of just 1μs ensures high positional accuracy, which is essential for robotics, RC models, and small automation systems. The servo comes with a 25cm cable and a JR-type connector, making it compatible with most popular RC receivers and microcontroller platforms, including JR and Futaba systems. Its compact dimensions (23 × 12.2 × 29mm) make it easy to integrate into space-constrained designs.

Servo 2 Click accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Output Channel Control
PA0
AN
ID SEL
PA7
RST
SPI Select / ID COMM
PD4
CS
SPI Clock
PC6
SCK
SPI Data OUT
PC5
MISO
SPI Data IN
PC4
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Grayscale PWM control
PB0
PWM
Error Detection
PA6
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

Servo 2 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Board mapper by product8 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
PIC18F57Q43 Curiosity 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

Servo 2 Click demo application is developed using the NECTO Studio, ensuring compatibility with mikroSDK's open-source libraries and tools. Designed for plug-and-play implementation and testing, the demo is fully compatible with all development, starter, and mikromedia boards featuring a mikroBUS™ socket.

Example Description
This example demonstrates the use of the Servo 2 Click board for controlling the angle of servo motors. The board is capable of driving multiple servos, and the example illustrates how to change the angle of all connected servos simultaneously within a defined range.

Key functions:

  • servo2_cfg_setup - Config Object Initialization function.

  • servo2_init - Initialization function.

  • servo2_set_angle - This function sets the servo angle for a specific channel or all channels.

  • servo2_update_output - This function updates the PWM output values for all channels by writing them to the device.

  • servo2_set_channel_pwm - This function sets the PWM output for a specific channel or all channels.

Application Init
Initializes the logger module and configures the Servo 2 Click board. The PWM communication is established, and the device is prepared for controlling the servos.

Application Task
Gradually changes the angle of all connected servo motors from a minimum to a maximum value, and then back to the minimum, creating a sweeping motion. The current angle is logged during each update.

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 Servo 2 Click example
 *
 * # Description
 * This example demonstrates the use of the Servo 2 Click board for controlling the angle of servo motors. 
 * The board is capable of driving multiple servos, and the example illustrates how to change the angle 
 * of all connected servos simultaneously within a defined range.
 *
 * The demo application is composed of two sections:
 *
 * ## Application Init
 * Initializes the logger module and configures the Servo 2 Click board. The PWM communication is 
 * established, and the device is prepared for controlling the servos.
 *
 * ## Application Task
 * Gradually changes the angle of all connected servo motors from a minimum to a maximum value, and 
 * then back to the minimum, creating a sweeping motion. The current angle is logged during each update.
 *
 * @note
 * Ensure that the servo motors are properly connected to the Servo 2 Click board and are compatible 
 * with the specified angle range such as the SG90 Micro Servo motors.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "servo2.h"

static servo2_t servo2;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    servo2_cfg_t servo2_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.
    servo2_cfg_setup( &servo2_cfg );
    SERVO2_MAP_MIKROBUS( servo2_cfg, MIKROBUS_1 );
    if ( PWM_ERROR == servo2_init( &servo2, &servo2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    static uint8_t angle = SERVO2_ANGLE_MIN;
    static int8_t step = 1;
    log_printf( &logger, "All channels angle: %u\r\n\n", angle );
    servo2_set_angle ( &servo2, SERVO2_CHANNEL_ALL, angle );
    servo2_update_output ( &servo2 );
    angle += step;
    if ( angle > SERVO2_ANGLE_MAX )
    {
        step = -step;
        angle += step;
    }
    else if ( angle < SERVO2_ANGLE_MIN )
    {
        step = -step;
        angle += step;
    }
}

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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