Intermediate
30 min

Decode, express, and amplify data across diverse applications with MCP4728 and ATmega644P

Empower data expression

DAC 4 Click with EasyAVR v7

Published Aug 18, 2023

Click board™

DAC 4 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644P

Designed for precision, it transforms digital insights into analog realities, enabling seamless communication and decision-making

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Hardware Overview

How does it work?

DAC 4 Click is based on the MCP4728, a quad, 12-bit voltage output Digital-to-Analog converter (DAC) with nonvolatile memory (EEPROM) from Microchip. Its onboard precision output amplifier allows it to achieve rail-to-rail analog output swing. The DAC input codes, device configuration bits, and I2C address bits are programmable to the nonvolatile memory (EEPROM) using I2C serial interface commands. The nonvolatile memory feature enables the DAC device to hold the DAC input codes during power-off time, allowing the DAC outputs to be available immediately after power-up with the saved settings. The MCP4728 device has a high-precision internal voltage reference (VREF = 2.048V). The user can select the internal reference, or an external reference may be used (VDD) for each channel individually. This

gives the ADC 4-click good flexibility for use in various applications. Each channel can be operated individually in Normal mode or Power-Down mode by setting the configuration register bits. In Power-Down mode, most of the internal circuits in the powered-down channel are turned off for power savings, and the output amplifier can be configured to present a known low, medium, or high resistance output load. This device also includes a Power-on Reset (POR) circuit to ensure reliable power-up and an onboard charge pump for the EEPROM programming voltage. The MCP4728 has four output pins routed to the output terminal blocks (TB1 and TB2). The output range of the DAC is 0 V to VREF or 0 V to 2×V REF. The communication with the main MCU is established over a two-wire I2C compatible serial

interface, with standard (100 kHz), fast (400 kHz), or high speed (3.4 MHz) modes supported. The I2C lines (SCL and SDA) are routed to the dedicated mikroBUS™pins. The LDA pin is a multipurpose GPIO: It can be used as Synchronization input or for the device I2C address selection. RDY pin can also optionally be used to monitor the status of EEPROM programming activity. 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.

DAC 4 Click top side image
DAC 4 Click bottom side 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

Architecture

AVR

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

4096

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
Multipurpose Pin
PD4
PWM
Data Ready
PD2
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC0
SCL
I2C Data
PC1
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

DAC 4 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 DAC 4 Click driver.

Key functions:

  • dac4_voltage_reference_set - Setting channel voltage reference values

  • dac4_gain_set - Writing channel gain values

  • dac4_data_report - Reading channel data and forming reports

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 
 * \brief Dac4 Click example
 * 
 * # Description
 * This application enables usage of digital to analog converter.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes I2C driver, executes general call reset and wake up commands.
 * 
 * ## Application Task  
 * Changes the output voltage of channels every 3 seconds, and displays
 * the channels status on the USB UART.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "dac4.h"

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

static dac4_t dac4;
static log_t logger;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

void dac4_log_report ( uint8_t channel_no )
{
    dac4_channel_setting_t dac4_channel_buffer[ 8 ];

    dac4_data_report ( &dac4, dac4_channel_buffer );
    channel_no *= 2;
    
    log_printf( &logger, "--- Power ON bit: " );
    switch ( dac4_channel_buffer[ channel_no ].por_bit )
    {
        case 0:
        {
            log_printf( &logger,"Power OFF\r\n" );
            break;
        }
        case 1:
        {
            log_printf( &logger, "Power ON\r\n" );
            break;
        }
        default :
        {
            break;
        }
    }

    log_printf( &logger, "--- V reference    : " );
    switch ( dac4_channel_buffer[ channel_no ].voltage_reference )
    {
        case DAC4_VREF_EXTERNAL:
        {
            log_printf( &logger, "External\r\n" );
            break;
        }
        case DAC4_VREF_INTERNAL:
        {
            log_printf( &logger, "Internal\r\n" );
            break;
        }
        default :
        {
            break;
        }
    }

    log_printf( &logger, "--- Power mode     : " );
    switch ( dac4_channel_buffer[ channel_no ].power_mode )
    {
        case DAC4_MODE_NORMAL:
        {
            log_printf( &logger, "Normal\r\n" );
            break;
        }
        case DAC4_MODE_1kOhm:
        {
            log_printf( &logger, "1 kOhm\r\n" );
            break;
        }
        case DAC4_MODE_100kOhm:
        {
            log_printf( &logger, "100 kOhm\r\n" );
            break;
        }
        case DAC4_MODE_500kOhm:
        {
            log_printf( &logger, "500 kOhm\r\n" );
            break;
        }
        default :
        {
            break;
        }
    }

    log_printf( &logger, "--- Gain value     : " );
    switch ( dac4_channel_buffer[ channel_no ].gain_value )
    {
        case DAC4_MODE_NORMAL:
        {
            log_printf( &logger, "1x Gain\r\n" );
            break;
        }
        case DAC4_MODE_1kOhm:
        {
            log_printf( &logger, "2x Gain\r\n" );
            break;
        }
        default :
        {
            break;
        }
    }
    
    log_printf( &logger, "--- DAC input data : %d  [0-4095]\r\n", dac4_channel_buffer[ channel_no ].dac_input_data );
    log_printf( &logger, "-------------------------------------\r\n" );
}

void dac4_set_output ( uint8_t channel_set )
{
    dac4_channel_setting_t dac4_channel_x;
    static uint16_t aux_dac_input_data = 0;
    
    dac4_channel_x.channel_select = channel_set;
    dac4_channel_x.udac_bit = DAC4_UPDATE;
    dac4_channel_x.voltage_reference = DAC4_VREF_EXTERNAL;
    dac4_channel_x.power_mode = DAC4_MODE_NORMAL;
    dac4_channel_x.gain_value = DAC4_GAIN_x1;
    dac4_channel_x.dac_input_data = aux_dac_input_data;

    if ( 0 != dac4_single_write( &dac4, &dac4_channel_x ) )
    {
        log_printf( &logger, "--- Fatal ERROR !!! \r\n" );
    }
    else
    {
        log_printf( &logger, "------------------------------------- \r\n" );
        log_printf( &logger, "--- Output setup done \r\n" );
        log_printf( &logger, "------------------------------------- \r\n" );
        aux_dac_input_data += 500;
        if ( aux_dac_input_data > 4095 )
        {
            aux_dac_input_data = 0;
        }
    }
}

void dac4_channel_report ( )
{
    log_printf( &logger, "\r\n -----> Channel A \r\n" );
    dac4_set_output( DAC4_CHANNEL_A );
    dac4_log_report( 0 );
    Delay_ms( 3000 );
    
    log_printf( &logger, "\r\n -----> Channel B \r\n" );
    dac4_set_output( DAC4_CHANNEL_B );
    dac4_log_report( 1 );
    Delay_ms( 3000 );
    
    log_printf( &logger, "\r\n -----> Channel C \r\n" );
    dac4_set_output( DAC4_CHANNEL_C );
    dac4_log_report( 2 );
    Delay_ms( 3000 );
    
    log_printf( &logger, "\r\n -----> Channel D \r\n" );
    dac4_set_output( DAC4_CHANNEL_D );
    dac4_log_report( 3 );
    Delay_ms( 3000 );
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    dac4_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.

    dac4_cfg_setup( &cfg );
    DAC4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    dac4_init( &dac4, &cfg );
    log_info( &logger, "---- Application ----" );

    Delay_ms( 500 );
    dac4_general_call_reset( &dac4 );
    Delay_ms( 500 );
    dac4_general_call_wake_up( &dac4 );
    Delay_ms( 500 );

    log_printf( &logger, "--- App init done \r\n \r\n" );
}

void application_task ( void )
{
    dac4_channel_report( );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources

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