Convert digital information into adjustable electrical signals with MCP4921 and PIC32MZ2048EFM100

Help your projects understand and work with different kinds of signals more accurately

Published Jan 23, 2024

Click board™

DAC Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Convert digital signals into analog insights across various applications. Experience the transformation of raw data into actionable understanding with unparalleled precision.

Hardware Overview

How does it work?

DAC Click is based on the MCP4921, a 12-bit DAC with an SPI interface from Microchip. It utilizes a resistive string architecture, with its inherent advantages of low DNL error, low ratio metric temperature coefficient, and fast settling time over an extended temperature range. The analog output is provided on the VOUT screw terminal. The VOUT can swing from approximately 0V to approximately VCC voltage, in the case of this Click board™, 3.3V or 5V. The analog signal on the reference pin of the MCP4921 is utilized to set the reference voltage on

the string DAC. The reference voltage can be selected between the VCC and the 4.096V given by the MCP1541 via the REF SEL jumper. DAC Click uses the SPI serial interface over the mikroBUS™ socket to communicate with the host MCU, with 20MHz clock support. The 12-bit data is sent to the DAC through the SPI interface. This interface is also used to enter the Shutdown mode, during which the supply current is isolated from most of the internal circuitry. The Power-on-Reset (POR) circuit allows the device to continue to have a

high-impedance output until a valid command is performed to the DAC registers, thus ensuring a reliable power-up. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR 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.

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

RST

SPI Chip Select

RPD4

SPI Clock

RPD1

SCK

SPI Data OUT

RPD14

MISO

SPI Data IN

RPD3

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

Curiosity PIC32 MZ EF MB 1 Access - upright/background hardware assembly

Curiosity PIC32 MZ EF MCU Step hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step 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 Click driver.

Key functions:

dac_set_voltage_pct - This function is used to set output voltage in percents
dac_set_voltage - This function is used to set output voltage

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 Dac Click example
 * 
 * # Description
 * This demo example sends digital signal to the outputs 
 * and converts it to analog.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver, SPI communication and LOG.
 * 
 * ## Application Task  
 * Sends different values( form 0 to 4095 with step 1000 ) to output and 
 * prints expected measurement.
 * 
 * \author Jovan Stajkovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "dac.h"

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

static dac_t dac;
static log_t logger;
static uint32_t dac_val;

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


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

void application_init ( void )
{
    log_cfg_t log_cfg;
    dac_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.

    dac_cfg_setup( &cfg );
    DAC_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    dac_init( &dac, &cfg );
}

void application_task ( void )
{
    //  Task implementation.    
    for ( dac_val = 0; dac_val <= DAC_RESOLUTION; dac_val += DAC_STEP_VALUE )
    {
        dac_set_voltage( &dac, dac_val );
        dac_val *= DAC_CALIB_VAL_1;
        dac_val /= DAC_CALIB_VAL_2;
        log_printf( &logger, " Current DAC Value: %d mV \r\n", dac_val );

        log_printf( &logger, "----------------------------------\r\n" );

        Delay_ms( 2000 );
    }
}

void main ( void )
{
    application_init( );

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

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