Step into the world of digital data with MCP3551 and PIC18F47K42TQFP
Where analog meets digital
Published Feb 13, 2024
Click board™
ADC 2 Click
Dev Board
Curiosity Nano with PIC18F47K42
Compiler
NECTO Studio
MCU
PIC18F47K42TQFP
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Hardware Overview
How does it work?
ADC 2 Click is based on the MCP3551, a 22-bit precise single-channel ΔΣ analog-to-digital converter from Microchip. The MCP3551 includes fully differential analog input on a VIN terminal, a third-order delta-sigma modulator, a fourth-order modified SINC decimation filter (allows superior averaging performance), an on-chip, low-noise internal oscillator, a power supply monitoring circuit, and an SPI digital interface. It can be easily used to measure low-frequency, low-level signals such as those found in pressure transducers, temperature, strain gauges, industrial control, or process control applications. This Click board™ communicates with MCU through a 3-Wire SPI interface (read-only) with a maximum frequency of 5MHz. The interface offers two conversion modes: A single Conversion mode for multiplexed
applications and a Continuous Conversion mode for multiple conversions in series, where every conversion is independent of each other (all internal registers are flushed between conversions). When the MCP3551 is not converting, it automatically goes into Shutdown mode, characterized by low power consumption. The MCP3551 provides single-cycle conversions with no digital filter settling time. Every conversion includes an internal offset and gain auto-calibration to reduce device error, which is transparent to the user and done in real-time during the conversion, allowing multiplexed applications. Like any ADC, the MCP3551 uses a reference voltage as the differential voltage range. The reference voltage level selection is performed by positioning the SMD jumper labeled as VREF
SEL to an appropriate position choosing between 3.3V or 5V provided by the mikroBUS™ power rails or 4.096V provided by MCP1541. These voltages may be used as the reference input that results in accuracy and stability. Besides, the ADC 2 Click supports an external power supply for the MCP3551, which can be connected to the input terminal labeled as VCC OUT and should be within the range of 2.7V to 5.5V. 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. However, the 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
PIC18F47K42 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate the PIC18F47K42 microcontroller (MCU). Central to its design is the inclusion of the powerful PIC18F47K42 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 2.3V to 5.1V (limited by USB input voltage), 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
40
RAM (Bytes)
8192
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 PIC18F47K42 as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for ADC 2 Click driver.
Key functions:
adc2_adc_Value_Read- Function is used to read specific data from ADC convertor.adc2_check_Over_Low- Function is used to check overflow low state.adc2_check_Over_High- Function is used to check overflow high state.
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 Adc2 Click example
*
* # Description
* This application enables usage of the 22bit ADC.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initalizes SPI driver and makes an initial log.
*
* ## Application Task
* This is an example that shows the capabilities of the ADC 2 click
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "adc2.h"
// ------------------------------------------------------------------ VARIABLES
static adc2_t adc2;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
adc2_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.
adc2_cfg_setup( &cfg );
ADC2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
adc2_init( &adc2, &cfg );
Delay_ms( 100 );
adc2_set_vref( &adc2, ADC2_VCC_3v3 );
log_printf( &logger, "------------------\r\n" );
log_printf( &logger, " ADC 2 Click \r\n" );
log_printf( &logger, "------------------\r\n" );
}
void application_task ( void )
{
float adc_val;
// Task implementation.
adc_val = adc2_read_adc_data( &adc2 );
log_printf( &logger, "Value : %.2f mV\r\n", adc_val );
if ( adc2.ovf_h )
log_printf( &logger, "HIGH OVERFLOW DETECTED\r\n" );
else if ( adc2.ovf_l )
log_printf( &logger, "LOW OVERFLOW DETECTED\r\n" );
log_printf( &logger, "------------------\r\n" );
Delay_ms( 500 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
