Intermediate
20 min

Determine the electron activity in a liquid, essential for understanding its ORP, with EZO-ORP™ and PIC18F57Q43

Oxidation/Reduction Potential (ORP) - Where it's crucial to ensure water is free from pathogens!

EZO Carrier Click - ORP with Curiosity Nano with PIC18F57Q43

Published Feb 27, 2024

Click board™

EZO Carrier Click - ORP

Dev.Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Measure the ORP of liquids for evaluating water quality and chemical reactions in water treatment, environmental monitoring, and chemical production

A

A

Hardware Overview

How does it work?

EZO Carrier Click - ORP is based on the EZO-ORP™, an ISO 11271 compliant embedded ORP (Oxidation/Reduction Potential) circuit board from Atlas Scientific. It allows you to interface any type and brand of measurement probe, which determines the liquid's oxidation/reduction potential in your application by sinking the probe into the solvent you want to measure the electron activity. The EZO Carrier Click - ORP comes with the BNC connector for interfacing the appropriate probe, like the Consumer Grade ORP probe. The EZO-ORP™ needs to be isolated from the host MCU; therefore, this Click™ board comes with the Si8400AB, a bidirectional isolator from Skyworks. The isolator provides standard bidirectional and I2C communication with a clock frequency of up to

1.7MHz. This circuit is a very sensitive device, and the sensitivity gives it its accuracy. It can read micro-voltages that are bleeding into the water from unnatural sources such as pumps, solenoid valves, or other probes/sensors. So, to eliminate the electrical noise, besides the Si8400AB isolator, the power supply voltage is also isolated. For this purpose, this Click™ board is equipped with the ROE-0505S, a DC/DC converter from Recom. EZO Carrier Click - ORP can use a standard 2-wire UART interface to communicate with the host MCU with the default baud rate of 9600bps. While using the UART interface, you can use the library we provide or a simple ASCII set of commands. You can also choose a standard 2-wire I2C interface over the COMM SEL jumpers. From calibration to

timed readings, the Atlas Scientific EZO-ORP™ circuit is a drop-in solution to a complex measurement. It features sleep mode, continuous operation, find function, export/import calibration, on-module status LED, and many more features detailed and described in the attached datasheet. 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.

EZO Carrier Click - ORP 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

Consumer-grade ORP probe from Atlas Scientific is an excellent option for various water testing needs, environmental monitoring, basic lab experiments, and initial product development stages. Designed for light-duty applications, it offers reliable ORP measurements within a range of -1100mV to +1100mV with an accuracy of ±1.1mV. With a rapid response time of 95% in just 1 second, it provides quick data acquisition for timely analysis. Operating effectively within a temperature range of 1 to 60°C, it suits diverse environmental conditions. However, it's essential to note that this probe isn't suitable for use in strong acids, bases, or industrial equipment environments. It is designed for moderate test depths with a maximum pressure tolerance of 50 PSI and a maximum depth rating of 35 meters (114 feet). Additionally, its 1-meter cable length offers convenience in installation and maneuverability.

EZO Carrier Click - ORP accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
ID COMM
PD4
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
UART TX
PC2
TX
UART RX
PC3
RX
I2C Clock
PB1
SCL
I2C Data
PB2
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

EZO Carrier Click - ORP 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
Curiosity Nano with PICXXX 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
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

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 EZO Carrier Click - ORP driver.

Key functions:

  • ezocarrierorp_send_cmd - Send command function

  • ezocarrierorp_send_cmd_with_par - Send command function with parameter

  • ezocarrierorp_send_cmd_check - Check the sent command

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 EZO Carrier ORP Click Example.
 *
 * # Description
 * This example demonstrates the use of EZO Carrier ORP click board by processing
 * the incoming data and displaying them on the USB UART.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver, performs the click default factory reset, and single point calibration 
 * with a calibration solutio with 225 mV ORP value.
 *
 * ## Application Task
 * Reads and processes all incoming oxidation-reduction potential data from the probe, and displays them on the USB UART in mV.
 *
 * ## Additional Function
 * - static void ezocarrierorp_clear_app_buf ( void )
 * - static void ezocarrierorp_log_app_buf ( void )
 * - static err_t ezocarrierorp_process ( ezocarrierorp_t *ctx )
 * - static err_t ezocarrierorp_rsp_check ( ezocarrierorp_t *ctx, uint8_t *rsp )
 * - static void ezocarrierorp_error_check ( err_t error_flag )
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "ezocarrierorp.h"

// Application buffer size
#define APP_BUFFER_SIZE             200
#define PROCESS_BUFFER_SIZE         200

static ezocarrierorp_t ezocarrierorp;
static log_t logger;

static uint8_t app_buf[ APP_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;
static err_t error_flag;

/**
 * @brief EZO Carrier ORP clearing application buffer.
 * @details This function clears memory of application buffer and reset its length.
 * @note None.
 */
static void ezocarrierorp_clear_app_buf ( void );

/**
 * @brief EZO Carrier ORP log application buffer.
 * @details This function logs data from application buffer to USB UART.
 * @note None.
 */
static void ezocarrierorp_log_app_buf ( void );

/**
 * @brief EZO Carrier ORP data reading function.
 * @details This function reads data from device and concatenates data to application buffer. 
 * @param[in] ctx : Click context object.
 * See #ezocarrierorp_t object definition for detailed explanation.
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t ezocarrierorp_process ( ezocarrierorp_t *ctx );

/**
 * @brief Response check.
 * @details This function checks for response and
 * returns the status of response.
 * @param[in] rsp  Expected response.
 * @return @li @c  0 - OK response.
 *         @li @c -1 - Error response.
 *         @li @c -2 - Timeout error.
 * See #err_t definition for detailed explanation.
 */
static err_t ezocarrierorp_rsp_check ( ezocarrierorp_t *ctx, uint8_t *rsp );

/**
 * @brief Check for errors.
 * @details This function checks for different types of
 * errors and logs them on UART or logs the response if no errors occured.
 * @param[in] error_flag  Error flag to check.
 */
static void ezocarrierorp_error_check ( err_t error_flag );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ezocarrierorp_cfg_t ezocarrierorp_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.
    ezocarrierorp_cfg_setup( &ezocarrierorp_cfg );
    EZOCARRIERORP_MAP_MIKROBUS( ezocarrierorp_cfg, MIKROBUS_1 );
    if ( UART_ERROR == ezocarrierorp_init( &ezocarrierorp, &ezocarrierorp_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_printf( &logger, "Device status \r\n" );
    ezocarrierorp_send_cmd( &ezocarrierorp, EZOCARRIERORP_CMD_STATUS );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_OK );
    ezocarrierorp_error_check( error_flag );

    log_printf( &logger, "Factory reset \r\n" );
    ezocarrierorp_send_cmd( &ezocarrierorp, EZOCARRIERORP_CMD_FACTORY );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_READY );
    ezocarrierorp_error_check( error_flag );

    log_printf( &logger, "Device info \r\n" );
    ezocarrierorp_send_cmd( &ezocarrierorp, EZOCARRIERORP_CMD_DEV_INFO );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_OK );
    ezocarrierorp_error_check( error_flag );

    uint8_t n_cnt = 0;
    uint8_t last_reading[ APP_BUFFER_SIZE ] = { 0 };
    ezocarrierorp_clear_app_buf( );
    ezocarrierorp_send_cmd( &ezocarrierorp, EZOCARRIERORP_CMD_SINGLE_READ );
    ezocarrierorp_process ( &ezocarrierorp );
    strcpy( last_reading, app_buf );
    log_printf( &logger, "Place the probe into the calibration solution,\r\n" );
    log_printf( &logger, "for single-point calibration \r\n" );
    Delay_ms( 5000 );
    log_printf( &logger, "Waiting for stable readings \r\n" );
    while ( n_cnt <= 5 )
    {
        if ( EZOCARRIERORP_OK == ezocarrierorp_process ( &ezocarrierorp ) )
        {  
            if ( 0 == strstr( app_buf, last_reading ) )
            {
                n_cnt++;
            }
            else
            {
                strcpy( last_reading, app_buf );
                n_cnt = 0;
            }
        }
        log_printf( &logger, "- " );
        Delay_ms( 1000 );
        ezocarrierorp_clear_app_buf( );
    }

    #define CALIBRATION_VALUE   "225"
    log_printf( &logger, "\r\n Calibration \r\n" );
    ezocarrierorp_send_cmd_with_par( &ezocarrierorp, EZOCARRIERORP_CMD_CAL, CALIBRATION_VALUE );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_OK );
    ezocarrierorp_error_check( error_flag );

    #define DISABLE_CONT_READ   "0"
    log_printf( &logger, "Disable continuous reading mode \r\n" );
    ezocarrierorp_send_cmd_with_par( &ezocarrierorp, EZOCARRIERORP_CMD_CONT_READ, DISABLE_CONT_READ );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_OK );
    ezocarrierorp_error_check( error_flag );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    log_printf( &logger, "Reading... \r\n" );
    ezocarrierorp_send_cmd( &ezocarrierorp, EZOCARRIERORP_CMD_SINGLE_READ );
    error_flag = ezocarrierorp_rsp_check( &ezocarrierorp, EZOCARRIERORP_RSP_OK );
    ezocarrierorp_error_check( error_flag );
    Delay_ms( 5000 );
}

void main ( void ) 
{
    application_init( );

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

static void ezocarrierorp_clear_app_buf ( void ) 
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
}

static void ezocarrierorp_log_app_buf ( void )
{
    for ( int32_t buf_cnt = 0; buf_cnt < app_buf_len; buf_cnt++ )
    {
        log_printf( &logger, "%c", app_buf[ buf_cnt ] );
    }
}

static err_t ezocarrierorp_process ( ezocarrierorp_t *ctx ) 
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t overflow_bytes = 0;
    int32_t rx_cnt = 0;
    int32_t rx_size = ezocarrierorp_generic_read( ctx, rx_buf, PROCESS_BUFFER_SIZE );
    if ( ( rx_size > 0 ) && ( rx_size <= APP_BUFFER_SIZE ) ) 
    {
        if ( ( app_buf_len + rx_size ) > APP_BUFFER_SIZE ) 
        {
            overflow_bytes = ( app_buf_len + rx_size ) - APP_BUFFER_SIZE;
            app_buf_len = APP_BUFFER_SIZE - rx_size;
            memmove ( app_buf, &app_buf[ overflow_bytes ], app_buf_len );
            memset ( &app_buf[ app_buf_len ], 0, overflow_bytes );
        }
        for ( rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( rx_buf[ rx_cnt ] ) 
            {
                app_buf[ app_buf_len++ ] = rx_buf[ rx_cnt ];
            }
        }
        return EZOCARRIERORP_OK;
    }
    return EZOCARRIERORP_ERROR;
}

static err_t ezocarrierorp_rsp_check ( ezocarrierorp_t *ctx, uint8_t *rsp )
{
    uint32_t timeout_cnt = 0;
    uint32_t timeout = 10000;
    err_t error_flag = EZOCARRIERORP_OK;
    ezocarrierorp_clear_app_buf( );
    while ( ( 0 == strstr( app_buf, rsp ) ) &&
    ( 0 == strstr( app_buf, EZOCARRIERORP_RSP_ERROR ) ) )
    {
        error_flag |= ezocarrierorp_process( ctx );
        if ( timeout_cnt++ > timeout )
        {
            ezocarrierorp_clear_app_buf( );
            return EZOCARRIERORP_ERROR_TIMEOUT;
        }
        Delay_ms( 1 );
    }
    Delay_ms( 100 );
    error_flag |= ezocarrierorp_process( ctx );
    if ( strstr( app_buf, rsp ) )
    {
        return EZOCARRIERORP_OK;
     }
    else if ( strstr( app_buf, EZOCARRIERORP_RSP_ERROR ) )
    {
        return EZOCARRIERORP_ERROR;
    }
    else
    {
        return EZOCARRIERORP_ERROR;
    }
}

static void ezocarrierorp_error_check ( err_t error_flag )
{
    switch ( error_flag )
    {
        case EZOCARRIERORP_OK:
        {
            ezocarrierorp_log_app_buf( );
            break;
        }
        case EZOCARRIERORP_ERROR:
        {
            log_error( &logger, " Error!" );
            break;
        }
        case EZOCARRIERORP_ERROR_TIMEOUT:
        {
            log_error( &logger, " Timeout!" );
            break;
        }
        default:
        {
            log_error( &logger, " Unknown!" );
            break;
        }
    }
    log_printf( &logger, "- - - - - - - - - - - - - - -\r\n" );
    Delay_ms( 500 );
}

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

Additional Support

Resources