Intermediate
30 min

Experience the efficiency of our 4-20mA current loop solution with DAC161S997 and ATmega324P

Enhance your process automation

4-20mA T 2 Click with EasyAVR v7

Published Aug 09, 2023

Click board™

4-20mA T 2 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega324P

Experience precise signal transmission with our advanced analog current loop transmitter, which provides seamless connectivity and compatibility with various industrial applications

A

A

Hardware Overview

How does it work?

4-20mA T 2 Click is based on the DAC161S997, a low-power 16-bit ΣΔ digital-to-analog converter (DAC) from Texas Instruments, realized as a ΣΔ modulator. Next to ΣΔ DAC, the DAC161S997 also contains an internal ultra-low power voltage reference and an internal oscillator to reduce power and component count in compact loop-powered applications. This architecture, where DAC's output current represents a multiplied copy of the filtered modulator output, ensures an excellent linearity performance while minimizing the device's power consumption. In addition to an industry-standard 4-20 mA current loop over the LOOP terminal, the DAC161S997 also has the possibility of a simple Highway Addressable

Remote Transducer (HART) modulator interfacing through an onboard HART TX terminal. It allows the injection of FSK-modulated digital data into the 4-20mA current loop. This Click board™ communicates with MCU using a 4-wire SPI serial interface with a maximum frequency of 10MHz, for data transfer and configuration of the DAC functions. The DAC161S997 supports both Mode 0 and Mode 3 of the SPI protocol. 4-20mA T 2 Click comes with an additional feature, as an interrupt, available on the ERR pin of the mikroBUS™ socket, the loop-error detection/reporting feature. By default, the DAC161S997 detects and reports several types of errors: loop error, SPI timeout error (channel error), frame error, and alarm current. In

the case of a fault condition or during the initial Power-Up sequence, the DAC161S997 will output current in either the upper or lower error current band. The band's choice is user-selectable via the appropriate position of an onboard jumper ERRL SEL, while the current error value is programmable through the SPI interface. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

4-20mA T 2 Click hardware overview image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. 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, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR 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 a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V 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 which cover a wide range of 16-bit AVR MCUs. EasyAVR 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.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU

ATmega324P

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
PA5
CS
SPI Clock
PB7
SCK
SPI Data OUT
PB6
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Loop-Error Interrupt
PD2
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

4-20mA T 2 Click Schematic schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

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

EasyAVR v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyAVR v7 Access DIP 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

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

This library contains API for 4-20mA T 2 Click driver.

Key functions:

  • c420mat2_set_output_current - 4-20mA T 2 set output current function

  • c420mat2_get_status - 4-20mA T 2 set status function

  • c420mat2_set_lower_limit - 4-20mA T 2 set lower limit function

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 4-20mA T 2 Click example
 *
 * # Description
 * This example demonstrates the use of 4-20mA T 2 Click board™.
 * This driver provides functions to configure 
 * analog output current transfer over an industry standard 4-20mA current loop.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of SPI module and log UART.
 * After driver initialization, default settings turn on the device.
 *
 * ## Application Task
 * This example demonstrates the use of the 4-20mA T 2 Click board™.
 * This example periodically changes the analog output current transfer 
 * from 4mA to 20mA and display status every 5 seconds.
 * Results are being sent to the UART Terminal, where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "c420mat2.h"

static c420mat2_t c420mat2;
static log_t logger;
static c420mat2_status_t status;

void display_status ( void )
{
    log_printf( &logger, " Status: \r\n" );
    if ( C420MAT2_STATUS_ERROR == status.ferr_sts )
    {
        log_printf( &logger, " - A frame error has occurred.\r\n" );
    }
    else
    {
        log_printf( &logger, " - No frame error occurred.\r\n" );
    }

    if ( C420MAT2_STATUS_ERROR == status.spi_timeout_err )
    {
        log_printf( &logger, " - The SPI interface has not received a valid command.\r\n" );
    }
    else
    {
        log_printf( &logger, " - The SPI interface has received a valid command.\r\n" );
    }

    if ( C420MAT2_STATUS_ERROR == status.loop_sts )
    {
        log_printf( &logger, " - A status loop error has occurred.\r\n" );
    }
    else
    {
        log_printf( &logger, " - No status loop error has occurred.\r\n" );
    }

    if ( C420MAT2_STATUS_ERROR == status.curr_loop_sts )
    {
        log_printf( &logger, " - A current loop error is occurring.\r\n" );
    }
    else
    {
        log_printf( &logger, " - No current loop error is occurring.\r\n" );
    }
    log_printf( &logger, " ----------------------------\r\n" );
}

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c420mat2_cfg_t c420mat2_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.
    c420mat2_cfg_setup( &c420mat2_cfg );
    C420MAT2_MAP_MIKROBUS( c420mat2_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == c420mat2_init( &c420mat2, &c420mat2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    if ( C420MAT2_ERROR == c420mat2_default_cfg ( &c420mat2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
    log_printf( &logger, " -----------------------------\r\n" );
    Delay_ms( 100 );
}

void application_task ( void )
{
    if ( C420MAT2_OK == c420mat2_set_output_current( &c420mat2, 4.0 ) )
    {
        log_printf( &logger, " Loop Current:  4.0 mA \r\n" );
        log_printf( &logger, " - - - - - - - - - - - - - - -\r\n" );
        if ( C420MAT2_OK == c420mat2_get_status ( &c420mat2, &status ) )
        {
            display_status( );    
        }
        Delay_ms( 5000 );
    }

    if ( C420MAT2_OK == c420mat2_set_output_current( &c420mat2, 10.0 ) )
    {
        log_printf( &logger, " Loop Current: 10.0 mA \r\n" );
        log_printf( &logger, " - - - - - - - - - - - - - - -\r\n" );
        if ( C420MAT2_OK == c420mat2_get_status ( &c420mat2, &status ) )
        {
            display_status( );    
        }
        Delay_ms( 5000 );
    }

    if ( C420MAT2_OK == c420mat2_set_output_current( &c420mat2, 15.0 ) )
    {
        log_printf( &logger, " Loop Current: 15.0 mA \r\n" );
        log_printf( &logger, " - - - - - - - - - - - - - - -\r\n" );
        if ( C420MAT2_OK == c420mat2_get_status ( &c420mat2, &status ) )
        {
            display_status( );    
        }
        Delay_ms( 5000 );
    }

    if ( C420MAT2_OK == c420mat2_set_output_current( &c420mat2, 20.0 ) )
    {
        log_printf( &logger, " Loop Current: 20.0 mA \r\n" );
        log_printf( &logger, " - - - - - - - - - - - - - - -\r\n" );
        if ( C420MAT2_OK == c420mat2_get_status ( &c420mat2, &status ) )
        {
            display_status( );    
        }
        Delay_ms( 5000 );
    }
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources

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