Transform inductance measurements into digital data using LDC1312-Q1 and STM32F103RB
Your inductance-to-digital transformer!
Published Oct 08, 2024
Click board™
LDC Click
Dev Board
Nucleo 64 with STM32F103RB MCU
Compiler
NECTO Studio
MCU
STM32F103RB
Unlock infinite possibilities with our inductance-to-digital marvel, which effortlessly converts inductance values into digital data, making it a vital component for real-time monitoring, quality control, and system automation
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Hardware Overview
How does it work?
LDC Click is based on the LDC1312-Q1, two-channel, 12-bit inductance to digital converters (LDCs) for inductive sensing solutions from Texas Instruments. This Click board™ is easy to use, requiring only the sensor frequency within 1kHz and 10MHz to begin sensing. It measures the oscillation frequency of an LC resonator and outputs a digital value proportional to frequency. Inductive sensing offers better performance, reliability, and flexibility than competitive technologies at lower cost and power. This board is ideal for exact short-range measurements of conductive targets' position, motion, or composition. Conductive objects in contact with an AC electromagnetic (EM) field will induce field changes that can be detected using a sensor such
as an inductor. Conveniently, an inductor and a capacitor are used to construct an LC resonator, also known as an LC tank, to produce an EM field. In the case of an LC tank, the effect of the field disturbance is an apparent shift in the inductance of the sensor, which can be observed as a shift in the resonant frequency - using this principle, the LDC1312-Q1 works. LDC Click communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 400kHz. In addition to I2C communication, two GPIO pins connected to the mikroBUS™ socket pins are also used. The SD pin routed to the RST pin of the mikroBUS™ socket, is used to place the LDC1312-Q1 in Shutdown mode, saving current, while the INT pin may be configured as an interrupt
to notify the host MCU of changes in system status. Besides, it also allows the choice of the least significant bit of its I2C slave address by positioning the SMD jumper labeled ADDR SEL to an appropriate position marked as 1 and 0. It also can connect additional external LC sensors, allowing you to replace the provided onboard sensor and solder your own at places marked with COIL1 and COIL2. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it 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
Nucleo-64 with STM32F103RB MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M3
MCU Memory (KB)
128
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
20480
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Nucleo 64 with STM32F103RB MCU 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 LDC Click driver.
Key functions:
ldc_get_interrupt- Get interrupt pin statusldc_get_frequency- Get frequency value calculated for specific channelldc_calculate_inductance- Calculate inductance relative to frequency
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 LDC Click example
*
* # Description
* This example showcases the ability of the device to detect
* metal objects. It configures a device for reading data from
* channel 0, checks if ID's are OK and reads data when interrupting
* is asserted and logs result.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of communication modules (I2C, UART) and
* additional pins. Then configures the device for reading data from
* channel 0, and checks if device ID's are correctly read, and
* read the currently set divider.
*
* ## Application Task
* Checks if interrupt pin is asserted, if so reads data from channel 0.
* Calculates and returns the frequency of the sensor. If the frequency
* is greater than 0, then it calculates the inductance of the sensor.
* It will log error and error values if it occurred.
*
* @author Luka Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "ldc.h"
#include "math.h"
static ldc_t ldc;
static log_t logger;
uint16_t divider;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
ldc_cfg_t ldc_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.
ldc_cfg_setup( &ldc_cfg );
LDC_MAP_MIKROBUS( ldc_cfg, MIKROBUS_1 );
err_t init_flag = ldc_init( &ldc, &ldc_cfg );
if ( I2C_MASTER_ERROR == init_flag )
{
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
if ( ldc_default_cfg ( &ldc ) < 0 )
{
log_error( &logger, " Default configuration. " );
for ( ; ; );
}
uint16_t temp_data = 0;
ldc_generic_read( &ldc, LDC_REG_MANUFACTURER_ID, &temp_data );
log_printf( &logger, "> Manufacturer ID: 0x%.4X\r\n", temp_data );
if ( LDC_MANUFACTURER_ID != temp_data )
{
log_error( &logger, " Manufacturer ID. " );
for ( ; ; );
}
ldc_generic_read( &ldc, LDC_REG_DEVICE_ID, &temp_data );
log_printf( &logger, "> Device ID 0x%.4X\r\n", temp_data );
if ( LDC_DEVICE_ID != temp_data )
{
log_error( &logger, " Device ID. " );
for ( ; ; );
}
ldc_generic_read( &ldc, LDC_REG_CLOCK_DIVIDERS_CH0, &temp_data );
divider = temp_data & 0x3FF;
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
if ( !ldc_get_interrupt( &ldc ) )
{
float frequency = 0.0;
float inductance = 0.0;
uint16_t status = 0;
ldc_generic_read( &ldc, LDC_REG_STATUS, &status );
if ( status & LDC_STATUS_DRDY )
{
err_t ret_val = ldc_get_frequency( &ldc, LDC_REG_DATA_CH0, divider, &frequency );
if ( !ret_val )
{
log_printf( &logger, "> Freq[MHz]: %.3f\r\n", frequency );
if ( frequency > 0 )
{
inductance = ldc_calculate_inductance( frequency );
}
log_printf( &logger, "> L[uH]: %.3f\r\n", inductance );
log_printf( &logger, "> ************************\r\n" );
Delay_ms ( 500 );
}
else
{
log_error( &logger, " Reading data: %ld", ret_val );
}
}
}
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
