Beginner
10 min

Convert multiple analog signals into digital data with MCP3204 and STM32F407VGT6

4-channel 12-bit ADC with SPI interface

ADC Click with Clicker 4 for STM32F4

Published Dec 29, 2023

Click board™

ADC Click

Dev. board

Clicker 4 for STM32F4

Compiler

NECTO Studio

MCU

STM32F407VGT6

Help electronics understand and work with information from the real world

A

A

Hardware Overview

How does it work?

ADC Click is based on the MCP3204, a 4-channel 12-bit A/D converter with SPI serial interface from Microchip. The MCP3204 contains an input channel selection multiplexer (CH0, CH1, CH2, CH3) which for reference can use the VCC (3.3V or 5V) or a 4.096V of the MCP1541 voltage reference from Microchip. The voltage reference determines the analog voltage range and can be selected via REFERENCE onboard jumper. To connect the

analog voltages to the ADC Click, utilize the four labeled terminals CH0-3 along with two GND terminals for referencing the ground. Each analog input pin goes through the MCP6284, a 5MHz rail-to-rail OpAmp from Microchip. The ADC Click uses a standard 4-Wire SPI serial interface to communicate with the host MCU, supporting both 0 and 3 of the SPI modes and operating at clock rates of up to 2MHz. Communication with the ADC

Click is initiated by bringing the CS line LOW. 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.

ADC Click hardware overview image

Features overview

Development board

Clicker 4 for STM32F4 is a compact development board designed as a complete solution that you can use to quickly build your own gadgets with unique functionalities. Featuring an STM32F407VGT6 MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core is an STM32F407VGT6 MCU, a powerful microcontroller by STMicroelectronics based on the high-performance

Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the

development board much simpler and, thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution that can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws.

Clicker 4 for STM32F4 double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M4

MCU Memory (KB)

10

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

100

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
PA4
CS
SPI Clock
PA5
SCK
SPI Data OUT
PA6
MISO
SPI Data IN
PA7
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

ADC Click Schematic schematic

Step by step

Project assembly

Clicker 4 for STM32F4 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Clicker 4 for STM32F4 as your development board.

Clicker 4 for STM32F4 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
Clicker 4 STM32F4 Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Clicker 4 for STM32F4 HA MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 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 ADC Click driver.

Key functions:

  • adc_get_single_ended_ch - Get Single-Ended Channel function

  • adc_get_differential_ch - Get Pseudo-Differential Pair function

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 ADC Click example
 *
 * # Description
 * This example demonstrates the use of ADC Click board.
 * The all channels can be configured as single-ended or pseudo-differential
 * pair.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes SPI driver, performs the reference voltage selection and
 * initializes UART console for results logging.
 *
 * ## Application Task
 * Reads voltage level of channels 0 and 1 in the both configurations,
 * single-ended and pseudo-differential pair, every 1 second.
 * All channels results will be calculated to millivolts [mV].
 *
 * *note:*
 * In single-ended mode the all channels must be in the range from Vss (GND)
 * to Vref (3V3 by default).
 * In pseudo-differential mode the IN- channel must be in the range from
 * (Vss - 100mV) to (Vss + 100mV). The IN+ channel must be in the range from
 * IN- to (Vref + IN-).
 * If any of conditions are not fullfilled, the device will return 0 or Vref
 * voltage level, and measurements are not valid.
 *
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "adc.h"


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

static adc_t adc;
static log_t logger;

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

void application_init( void )
{
    log_cfg_t log_cfg;
    adc_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.

    adc_cfg_setup( &cfg );
    ADC_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    adc_init( &adc, &cfg );
}

void application_task( void )
{
    adc_get_single_ended_ch( &adc, ADC_CH0_OR_CH01 );
    adc_get_single_ended_ch( &adc, ADC_CH1_OR_CH10 );
    adc_get_single_ended_ch( &adc, ADC_CH2_OR_CH23 );
    adc_get_single_ended_ch( &adc, ADC_CH3_OR_CH32 );
    adc_get_differential_ch( &adc, ADC_CH0_OR_CH01 );

    log_printf( &logger, "* CH0 = %u mV\r\n", adc.ch0 );
    log_printf( &logger, "* CH1 = %u mV\r\n", adc.ch1 );
    log_printf( &logger, "* CH2 = %u mV\r\n", adc.ch2 );
    log_printf( &logger, "* CH3 = %u mV\r\n", adc.ch3 );
    log_printf( &logger, "* CH0 - CH1 = %d mV\r\n", adc.ch01 );
    log_printf( &logger, "-----------------------------\r\n" );

    Delay_ms( 1000 );
}

void main( void )
{
    application_init( );

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


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

Additional Support

Resources

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