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ADC 12 Click with EasyPIC v7

Published Dec 29, 2023

Click board™

ADC 12 Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F27K42

Ready to take on even the most complex designs? Our ADC is up to the challenge!

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Hardware Overview

How does it work?

ADC 12 Click is based on the ADS7828, a low-power 12-bit data acquisition device with a serial I2C interface and an 8-channel multiplexer from Texas Instruments. The architecture of the ADS7828, which is a classic Successive Approximation Register (SAR) A/D converter, is based on capacitive redistribution that inherently includes a sample-and-hold function. It has an integrated I2C input and output port with screw terminal connectors for each analog input channel. An internally generated free-running clock controls it. When the ADS7828 is not performing conversions or being addressed, it keeps the A/D converter core powered off, and the internal clock does not operate. When the A/D converter enters the Hold mode, the voltage on the selected channel pin of the input

terminal is captured on the internal capacitor array. The input current on the analog inputs depends on the conversion rate of the device. During the sample period, the source must charge the internal sampling capacitor. There is no further input current after the capacitor has been fully charged. The amount of charge transfer from the analog source to the converter is a function of the conversion rate. ADC 12 Click communicates with MCU using the standard I2C 2-Wire interface with a frequency of up to 100kHz in the Standard, up to 400kHz in the Fast, and up to 3.4MHz in the High-Speed mode. It also allows the choice of the last two least significant bits (LSB), A0 and A1, by positioning SMD jumpers labeled ADDR SEL to an appropriate position marked as 0 and 1.

This Click board™ also possesses a jumper for selecting the reference voltage labeled as VREF SEL. The ADS7828 can operate with an internal 2.5V reference or an external reference (in this case, logic voltage level VCC), which can be selected by positioning SMD jumpers to an appropriate position marked as INT and EXT. 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. 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.

ADC 12 Click top side image
ADC 12 Click lateral side image
ADC 12 Click bottom side image

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.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

8192

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
2

Take a closer look

Schematic

ADC 12 Click Schematic 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.

EasyPIC v7 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v7 Access MB 2 - 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 12 Click driver.

Key functions:

  • void adc12_send_cmd ( uint8_t cmd_byte ); - Function is used to configure the device.
  • uint16_t adc12_single_ended ( uint8_t chan, uint16_t v_ref ); - Function is used to get raw ADC value.
  • uint16_t adc12_differential ( uint8_t chan, uint16_t v_ref ); - Function is used to get raw ADC value.

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 ADC12 Click example
 *
 * # Description
 * This example demonstrates the use of ADC 12 click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and sets the input and power-down modes.
 *
 * ## Application Task
 * Reads the RAW ADC data and converts it to voltage in milivolts and displays
 * both values on the USB UART every second.
 *
 * @note
 * With internal reference voltage set the click measures up to 2500 mV.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "adc12.h"

static adc12_t adc12;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    adc12_cfg_t adc12_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.

    adc12_cfg_setup( &adc12_cfg );
    ADC12_MAP_MIKROBUS( adc12_cfg, MIKROBUS_1 );
    err_t init_flag = adc12_init( &adc12, &adc12_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    adc12_set_sd_mode ( &adc12, ADC12_CMD_SD_SINGLE_END );
    adc12_set_pd_mode( &adc12, ADC12_CMD_PD_IRON_ADON );
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    uint16_t raw_adc;
    float voltage;

    adc12_read_raw_data ( &adc12, ADC12_SINGLE_END_CH0, &raw_adc );
    adc12_read_voltage ( &adc12, ADC12_SINGLE_END_CH0, ADC12_INTERNAL_VREF, &voltage );
    
    log_printf( &logger, " RAW ADC: %u \r\n", raw_adc );
    log_printf( &logger, " Voltage from Channel 0: %.2f mV \r\n", voltage );
    log_printf( &logger, " ---------------------------\r\n" );
    Delay_ms( 1000 );
}

void main ( void ) 
{
    application_init( );

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

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

Additional Support

Resources