Enhance energy efficiency with MLX75305 and STM32F030R8 by tailoring illumination to the available natural light
Let there be light data
Published Feb 26, 2024
Click board™
Ambient Click
Development board
Nucleo-64 with STM32F030R8 MCU
Compiler
NECTO Studio
MCU
STM32F030R8
Unlock the ability to monitor and control environmental conditions effortlessly, making your space more comfortable and energy-efficient
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Hardware Overview
How does it work?
Ambient Click is based on the MLX75305, a light-to-voltage SensorEyeC™ from Melexis Technologies. The MLX75305 is the second member of the SensorEyeC™ series of optical sensors designed for high-volume automotive, industrial, and consumer applications. It includes a photodiode, a trans-impedance amplifier to convert and amplify the photocurrent of the photodiode, and an open drain output buffer stage which gives a voltage value that varies
linearly with incident light, available on the AN pin of the mikroBUS™ socket. An internal configuration like this guarantees stable light responsivity over time and temperature and drastically improves noise behavior compared to discrete photodiode designs. Covering a spectral bandwidth from 500nm up to 1000nm, the MLX75305 maintains ±2% linearity across its whole output voltage range with a typical responsiveness of 70mV/(µW/cm²). Its unique features make it
suitable for measuring ambient light or controlling LED light in LCD backlight dimming applications. 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. Also, this 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
Nucleo-64 with STM32F030R8 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)
64
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
8192
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
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F030R8 MCU as your development board.
Track your results in real time
Application Output
After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.
After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.
Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.
Software Support
Library Description
This library contains API for Ambient Click driver.
Key functions:
ambient_read_an_pin_voltage- This function reads results of AD conversion of the AN pin and converts them to proportional voltage levelambient_get_light_intensity- Calculates the light intensity from analog voltage measurement of the Melexis MLX75305 on Ambient Click
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 Ambient Click example
*
* # Description
* This application turns light intensity into voltage.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization driver enables GPIO,initializationADC, also write log.
*
* ## Application Task
* This is an example which demonstrates the use of Ambient click board.
* Ambient click reads ADC value and converts to light intensity [ uW/cm2 ].
* Results are being sent to the Usart Terminal where you can track their changes.
* All data logs on USB uart change for every 1 sec.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "ambient.h"
// ------------------------------------------------------------------ VARIABLES
static ambient_t ambient;
static log_t logger;
uint16_t value_adc;
uint16_t light;
void application_init ( void )
{
log_cfg_t log_cfg;
ambient_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.
ambient_cfg_setup( &cfg );
AMBIENT_MAP_MIKROBUS( cfg, MIKROBUS_1 );
ambient_init( &ambient, &cfg );
log_printf( &logger, " Initialization ADC " );
Delay_ms( 100 );
}
void application_task ( void )
{
ambient_data_t tmp;
// Task implementation.
tmp = ambient_generic_read ( &ambient );
light = ambient_calculate_light_intensity( &ambient, tmp, AMBIENT_VCC_3_3, AMBIENT_RES_12_BIT );
log_printf( &logger, "** ADC value : [DEC]- %d, [HEX]- 0x%x \r\n", tmp, tmp );
log_printf( &logger, "Light Intensity: %d uW/cm2 \r\n", light );
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
