Convert digital information into adjustable electrical signals with MCP4921 and PIC18F57Q43
Help your projects understand and work with different kinds of signals more accurately
Published Feb 13, 2024
Click board™
DAC Click
Dev Board
Curiosity Nano with PIC18F57Q43
Compiler
NECTO Studio
MCU
PIC18F57Q43
Convert digital signals into analog insights across various applications. Experience the transformation of raw data into actionable understanding with unparalleled precision.
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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
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.
Microcontroller Overview
MCU Card / MCU
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.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.
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.
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™.
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.
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 percentsdac_set_voltage- This function is used to set output voltage
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
* \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
