Change analog signals to digital with MAX22005 and PIC18F46K42
Digitize your data
Published Mar 11, 2023
Click board™
ADC 18 Click
Dev Board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18F46K42
Translate analog signals for data processing purposes
A
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Hardware Overview
How does it work?
ADC 18 Click is based on the MAX22005, a high-performance twelve-channel analog-to-digital converter from Analog Devices. The MAX22005 has an integrated 24-bit delta-sigma ADC, input multiplexer, signal conditioning, and control logic block, allowing ADC to communicate with MCU through a high-speed serial interface. An integrated delta-sigma ADC is shared between all channels with an integrated 5ppm/°C precision reference. Using high-voltage, zero-drift input amplifiers, standard industrial analog input voltage ranges are converted to the ADC input voltage range. Input channels can be used as twelve single-ended, six differential, and up to eight multichannel configurable differential inputs. In total, the device supports up to 26 different configurations. The MAX22005 can also be configured as an analog-input
current-mode device using an external precision resistor per channel or configurable analog input using an external precision resistor and low-cost switch per channel. All input ports are robustly protected up to ±36V reverse polarity and ±2kV surge pulses without the need for TVS diodes and factory calibrated with a best-in-class system performance of less than 0.05% FSR Total-Unadjusted-Error (TUE) over temperature. ADC 18 Click communicates with MCU through a standard SPI interface and operates at clock rates up to 30MHz, for all configurations and information management and acquiring conversion results. In addition, it also uses several mikroBUS™ pins. An active-low reset signal routed on the RST pin of the mikroBUS™ socket activates a hardware reset of the system, while the INT pin on the mikroBUS™
socket represents a standard interrupt feature providing a user with feedback information. It also has an additional data-ready interrupt marked as RDY and routed on the AN pin of the mikroBUS™ socket, used to signal when a new ADC conversion result is available in the data register. This Click board™ can only be operated with a 3.3V logic voltage level. It also has an analog inputs external power supply terminal where it is necessary to bring ±15V to accept ± 10V inputs, whose full-scale range is ± 12.5V. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing 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)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ 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
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 ADC 18 Click driver.
Key functions:
adc18_set_active_channelThis function sets the active channel.adc18_start_conversionThis function starts the conversion with the selected data rate.adc18_read_voltageThis function reads RAW ADC value of previous conversion and converts it to 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 main.c
* @brief ADC18 Click example
*
* # Description
* This example demonstrates the use of ADC 18 click board by reading
* the voltage from 12 analog input single-ended channels.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and logger, and performs the click default configuration.
*
* ## Application Task
* Reads and displays the voltage from 12 analog input single-ended channels
* on the USB UART approximately once per second.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "adc18.h"
static adc18_t adc18;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
adc18_cfg_t adc18_cfg; /**< Click config object. */
/**
* 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.
adc18_cfg_setup( &adc18_cfg );
ADC18_MAP_MIKROBUS( adc18_cfg, MIKROBUS_1 );
if ( SPI_MASTER_ERROR == adc18_init( &adc18, &adc18_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( ADC18_ERROR == adc18_default_cfg ( &adc18 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
static uint8_t channel = ADC18_CH_AI1_SINGLE_ENDED;
if ( ADC18_OK == adc18_set_active_channel ( &adc18, channel ) )
{
adc18_start_conversion ( &adc18, ADC18_DATA_RATE_225_SPS );
// Waits for the availability of the conversion result
while ( adc18_get_rdy_pin ( &adc18 ) );
adc18_stop_conversion ( &adc18 );
float voltage;
if ( ADC18_OK == adc18_read_voltage ( &adc18, &voltage ) )
{
log_printf ( &logger, "Channel AI%u: %.2f V\r\n", channel + 1, voltage );
if ( ++channel > ADC18_CH_AI12_SINGLE_ENDED )
{
channel = ADC18_CH_AI1_SINGLE_ENDED;
log_printf ( &logger, "\r\n" );
Delay_ms ( 1000 );
}
}
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
