Precisely monitor voltage, current, and power levels with LTC2947 and STM32L073RZ
The VCP monitor that sets the bar
Published Feb 26, 2024
Click board™
VCP Monitor 3 Click
Dev. board
Nucleo-64 with STM32L073RZ MCU
Compiler
NECTO Studio
MCU
STM32L073RZ
We have developed a cutting-edge technology that offers comprehensive monitoring of voltage, current, and power to support reliable and stable electrical systems
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Hardware Overview
How does it work?
VCP Monitor 3 Click is based on the LTC2947, a high-precision power and energy monitor with an internal sense resistor supporting up to ±30A from Analog Devices. Input Range allows 0V to 15V bus voltages with 0.5% measurement accuracy. The LTC2947 is responsible for measuring current, voltage, power, charge and energy with 1% current and charge accuracy and 1.2% power and energy accuracy. Additional features include an alert indication in case some of the thresholds are exceeded, and user-configurable GPIO pin for various functions. The LTC2947 possesses internal 300µΩ, temperature-compensated sense resistor that minimizes efficiency loss and external components, simplifying energy measurement applications while enabling high accuracy current measurement over the full temperature range. All measured quantities are stored in internal registers accessible via the selectable I2C/SPI interface. The LTC2947 features programmable high and low thresholds for all measured quantities to reduce digital traffic with the host. Measuring a total of seven parameters: current, voltage, power, charge (coulombs), energy, and
run time, as well as its own chip temperature, makes this click board excellent for high variety of applications. Main chip LTC2947 includes three no latency delta-sigma analog-to-digital converters to simultaneously measure current, voltage, and power. It also measures die temperature and derives the accumulated quantities charge, energy, and time using an on-board oscillator. It stores these values in internal registers that can be read out via the serial interface, configurable as either I2C or SPI. The LTC2947 keeps track of the minimum and maximum measured values for each of the measured quantities. Thresholds can be set for each parameter, and the LTC2947 will set the corresponding bit in the Alert register and optionally alert the host by pulling low on the ALERT pin when a threshold is exceeded. A GPIO pin is included that can be used for four different purposes. It can be configured as a general-purpose-logic input or output, as an output to automatically control a fan based on the LTC2947’s internal silicon temperature measurement or as an input to enable and disable accumulation of charge, energy, and time. The LTC2947 measures
each input with an ADC specifically tailored for the task. Connections labeled as IM (Negative) and IP (Positive) are high side current sense inputs and must be tied in series with the load intended for the measurement. Voltage sense inputs VM (Negative) and VP (Positive) should be connected parallel to the load for a second ADC to measure the differential voltage between those two terminals. More information about the LTC2947’s functionality, electrical specifications, and typical performance can be found in the attached datasheet. VCP Monitor 3 Click supports both SPI and I2C communication interfaces, allowing it to be used with a wide range of different MCUs. The communication interface can be selected by moving SMD jumpers grouped under the COMM SEL to an appropriate position (SPI or I2C). The slave I2C address can also be configured by SMD jumpers under ADDR SEL when the Click board™ is operated in the I2C mode. This Click Board™ is designed to be operated with both 3.3V and 5V logic levels that can be selected via VCC SEL jumper. This allows for both 3.3V and 5V capable MCUs to use the communication lines properly.
Features overview
Development board
Nucleo-64 with STM32L073RZ 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-M0
MCU Memory (KB)
192
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 STM32L073RZ 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 VCP Monitor 3 Click driver.
Key functions:
vcpmonitor3_rd_page_0- Read Data From Page 0 functionvcpmonitor3_set_op_mode- Set Operation Mode functionvcpmonitor3_read_p- Read Power in Watts 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 VCPMonitor3 Click example
*
* # Description
* VCP Monitor 3 Click show it's full usage by reading current, voltage, power, die temperature
* and voltage at DVCC using SPI or I2C communication protocol.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initalizes SPI or I2C driver and sets up the device.
*
* ## Application Task
* This example shows capabilities of VCP Monitor 3 Click board
* by reading current, voltage, power, die temperature and
* voltage at DVCC and displaying the results via USART terminal.
*
* @author Mikroe Team
*
*/
#include "board.h"
#include "log.h"
#include "vcpmonitor3.h"
static vcpmonitor3_t vcpmonitor3;
static log_t logger;
static float cur_data;
static float volt_data;
static float pow_data;
static float die_temp;
static float volt_vcc;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
vcpmonitor3_cfg_t vcpmonitor3_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.
vcpmonitor3_cfg_setup( &vcpmonitor3_cfg );
VCPMONITOR3_MAP_MIKROBUS( vcpmonitor3_cfg, MIKROBUS_1 );
err_t init_flag = vcpmonitor3_init( &vcpmonitor3, &vcpmonitor3_cfg );
if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( VCPMONITOR3_ERROR == vcpmonitor3_default_cfg ( &vcpmonitor3 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
volt_data = vcpmonitor3_read_v( &vcpmonitor3 );
log_printf( &logger, " Voltage : %.2f V \r\n", volt_data );
cur_data = vcpmonitor3_read_i( &vcpmonitor3 );
log_printf( &logger, " Current : %.2f A \r\n", cur_data );
pow_data = vcpmonitor3_read_p( &vcpmonitor3 );
log_printf( &logger, " Power : %.2f W \r\n", pow_data );
die_temp = vcpmonitor3_read_temp( &vcpmonitor3 );
log_printf( &logger, " Die Temperature : %.2f C \r\n", die_temp );
volt_vcc = vcpmonitor3_read_vcc( &vcpmonitor3 );
log_printf( &logger, " Voltage at DVCC : %.2f V \r\n", volt_vcc );
log_printf( &logger, " ------------------------------- \r\n" );
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
