Step into the world of digital data with MCP3551 and PIC18F24K50
Where analog meets digital
Published Nov 01, 2023
Click board™
ADC 2 Click
Dev.Board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18F24K50
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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
EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.
Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 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.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
16
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
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 EasyPIC v8 as your development board.
Track your results in real time
Application Output
After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.
Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.
In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".
The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
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
