Beginner
10 min
0

Provide clear, accurate digital outputs from analog inputs using ADS127L11 and PIC18LF45K40

From waveform to wonder: Transform signals with unparalleled precision

ADC 23 Click with EasyPIC v7a

Published Nov 14, 2023

Click board™

ADC 23 Click

Development board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18LF45K40

Unleash the full potential of your analog signals as they transform into a realm of digital clarity, setting new standards in signal conversion.

A

A

Hardware Overview

How does it work?

ADC 23 Click is based on the ADS127L11, a wide-bandwidth 24-bit delta-sigma analog-to-digital converter from Texas Instruments. The digital filter is configurable for wide or low-latency operation, optimizing wideband AC performance or data throughput for DC signals. It is optimized to provide high resolution with low power consumption. The delta-sigma demodulator produces low-resolution, high-frequency data, after which the noise is removed. The digital filter simultaneously decimates and filters the modulator data, thus providing the high-resolution final output data. The ADS127L11 integrates input and reference buffers to reduce signal loading. You can choose onboard ADR4525, an ultralow noise high-accuracy voltage reference

from Analog Devices for a reference voltage. Or you can choose an external one over the VEXT header. The selection can be made over the VREF SEL jumper. The internal voltage reference of 2.5V is set by default. The ADC can operate with an external clock or an internal oscillator. The nominal value of the clock is 25.6MHz in high-speed mode and 3.2MHz in low-speed mode. You can add an external oscillator over the CLK header. The analog input of the ADC is differential, with the input defined as a difference voltage, and you should drive the input with a differential signal for the best performance. For this purpose, the ADC 23 Click is equipped with two SMA connectors. ADC 23 Click uses a standard 4-Wire SPI serial interface to communicate with the host MCU, supporting

SPI mode 1. The ADC can be reset over the RST pin. The start STR pin synchronizes the digital process, and if the STR pin is in a HIGH logic state, the ADC immediately begins conversions with the data-ready DRY pin pulsing for each conversion. The latency is defined as the time from synchronization to the falling edge of the DRY pin. 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.

ADC 23 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

PIC18LF45K40

Architecture

PIC

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset / ID SEL
RE1
RST
SPI Select / ID COMM
RE0
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Conversion Start
RC0
PWM
Data Ready
RB0
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

ADC 23 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 ADC 23 Click driver.

Key functions:

  • adc23_get_voltage - ADC 23 read get voltage level function.

  • adc23_read_conversion_data - ADC 23 read conversion data function.

  • adc23_start_conversion - ADC 23 start conversion function.

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 ADC 23 Click example
 *
 * # Description
 * This example demonstrates the use of the ADC 23 Click board™ 
 * by reading and writing data by using SPI serial interface and reading results of AD conversion.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of SPI module and log UART.
 * After driver initialization, the app executes a default configuration.
 *
 * ## Application Task
 * The demo application reads the voltage levels from analog input and displays the results.
 * Results are being sent to the UART Terminal, where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "adc23.h"

static adc23_t adc23;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    adc23_cfg_t adc23_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.
    adc23_cfg_setup( &adc23_cfg );
    ADC23_MAP_MIKROBUS( adc23_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == adc23_init( &adc23, &adc23_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( ADC23_ERROR == adc23_default_cfg ( &adc23 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
}

void application_task ( void )
{
    static float voltage = 0.0;
    if ( ADC23_OK == adc23_get_voltage( &adc23, &voltage ) )
    {
        log_printf( &logger, " Voltage : %.2f [mV]\r\n", voltage );
        Delay_ms( 1000 );
    } 
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources