Fine-tune resistance or any other parameter in a circuit with PTA3043-2015CPB103 and PIC18F4553

Precision in your hands: Redefine control with our mechanical slider

Published Oct 10, 2023

Click board™

Slider Click

Dev Board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F4553

Our mechanical slide potentiometer, equipped with built-in LEDs to visualize its position, is designed to revolutionize control and provide a smooth and accurate way to adjust various parameters while offering real-time visual feedback

Hardware Overview

How does it work?

Slider Click is based on two sections: the first section is the slider section itself, with the sliding potentiometer end terminals connected between GND and the VCC, and the wiper connected to the MCP3551 IC, which is a low-power, single-channel 22-bit delta-sigma ADC from Microchip. The slider acts as a voltage divider so that the voltage between the GND and the wiper position is determined by the slider position. This voltage is then applied to the input pin of the 22bit ADC converter and converted to a digital value. The MCP3551 has its SPI lines routed to the mikroBUS™ so that the values can be read easily

by the MCU. The second section of this Click board™ consists of the MAX6969, a well know 16-port, constant-current LED driver from Maxim Integrated, used to control the SMD LEDs. The MAX6969 IC uses the same SPI lines as the ADC, but to avoid data collision, different chip select (CS) line is used. While the ADC uses the CS line routed to the CS pin of the mikroBUS™, the LED driver uses the RST line of the mikroBUS™ as the chip select input. This allows to work with both ICs independently. MAX6969 output enable (OE) pin is routed to the AN pin of the mikroBUS™, making it easy to completely turn off the output stage

of the MAX6969, by setting this pin to a HIGH logic state. If left floating, this pin will be pulled down to the GND by the 10K resistor. The output LED current is constant and it is set to around 20mA by the resistor on the SET pin of the MAX6969. 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.

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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 v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block 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-B (USB-B) 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 v7 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.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

LED Driver Output Enable

RA2

LED Driver SPI Chip Select

RE1

RST

ADC SPI Chip Select

RE0

SPI Clock

RC3

SCK

SPI Data OUT

RC4

MISO

SPI Data IN

RC5

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

Buck 22 Click front image hardware assembly

EasyPIC v7 MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step 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.

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.

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".

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.

Software Support

Library Description

This library contains API for Slider Click driver.

Key functions:

slider_read_adc_and_ready - Function calls slider_readADC function, but first checks is ADC conversion finished
slider_enable_led_output - Function enables LED output to shows output laches when state is low, and disables LED output when state is high
slider_enable_output_laches - Function enables output laches to monitor converted ADC value, when state is high

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 Slider Click example
 * 
 * # Description
 * This example detect even the smallest move, faithfully capturing the smoothness of 
 * the slider movement, while digitizing its position.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes click driver
 * 
 * ## Application Task  
 * Converts analog input voltage (VCC), witch value depends on the slider position,
 * to digital output value, shows result of conversion on LED and logs result on USB UART.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "slider.h"

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

static slider_t slider;
static log_t logger;

static float adc_value;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    slider_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.

    slider_cfg_setup( &cfg );
    SLIDER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    slider_init( &slider, &cfg );
    Delay_ms( 200 );

}

void application_task ( void )
{
    adc_value = slider_write_output( &slider );
    log_printf( &logger, "%.2f\r\n", adc_value );
    Delay_ms( 100 );
}

void main ( void )
{
    application_init( );

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


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