Measure the ambient light intensity and detect the presence/absence of objects with TMD2755 and STM32C031C6
Precise measurements for both light and proximity even in challenging conditions
Published Oct 10, 2024
Click board™
Ambient 14 Click
Dev. board
Nucleo 64 with STM32C031C6 MCU
Compiler
NECTO Studio
MCU
STM32C031C6
Accurately detect light and proximity for optimized device control
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Hardware Overview
How does it work?
Ambient 14 Click is based on the TMD2755, an advanced sensor from ams OSRAM that combines digital ambient light sensing (ALS) and proximity detection in a highly compact 1.1mm module. The TMD2755 integrates an infrared VCSEL (Vertical-Cavity Surface-Emitting Laser) and a factory-calibrated VCSEL driver for efficient proximity detection. This sensor excels in detecting objects, such as recognizing the proximity of a user's ear to a mobile device screen, by measuring the reflected IR energy emitted by the integrated VCSEL. The board's proximity detection capabilities are supported by a sophisticated proximity engine, which includes an offset adjustment feature to eliminate unwanted reflections from nearby objects, enhancing accuracy. It also improves proximity
measurements by automatically subtracting ambient light interference. The results from both ALS and proximity detection are provided as 16-bit data, enabling precise measurement of ambient light levels for tasks like adjusting display backlight brightness. This Click board™ uses a standard 2-wire I2C interface to communicate with the host MCU, supporting Standard mode with up to 1MHz of frequency clock. It also provides interrupt-driven detect/release events through the INT pin on the mikroBUS™ socket. These interrupts are triggered when proximity results exceed or fall below user-configured threshold levels. The TMD2755 does not require a specific Power-Up sequence but requires a voltage of 1.8V for its interface and logic part to work correctly. Therefore, a small regulating LDO,
the BH18PB1WHFV, provides a 1.8V out of 3.3V mikroBUS™ power rail. Since the sensor operates on 1.8V, this Click board™ also features the PCA9306 voltage-level translator, allowing the TMD2755 to work properly with 3.3V and 5V MCU. This regulator can be activated via the SBY pin of the mikroBUS™ socket, providing an enable function simultaneously. 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 STM32C031C6 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)
32
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
12K
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 STM32C031C6 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 Ambient 14 Click driver.
Key functions:
ambient14_read_proximity- This function reads the raw proximity data. The higher the value, the closer the detected object is.ambient14_read_als_ir- This function reads the raw ALS and IR data.ambient14_get_illuminance- This function calculates the illuminance level (Lux) from ALS data counts input.
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 Ambient 14 Click example
*
* # Description
* This example demonstrates the use of Ambient 14 click board by measuring
* the illuminance level (Lux) and the proximity data on the USB UART.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Reads the proximity, ALS, and IR raw data counts when data is ready.
* Calculates the illuminance level in Lux from ALS data counts and displays
* the results on the USB UART approximately every 500ms.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "ambient14.h"
static ambient14_t ambient14;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
ambient14_cfg_t ambient14_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.
ambient14_cfg_setup( &ambient14_cfg );
AMBIENT14_MAP_MIKROBUS( ambient14_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == ambient14_init( &ambient14, &ambient14_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( AMBIENT14_ERROR == ambient14_default_cfg ( &ambient14 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint16_t proximity = 0;
uint16_t als_data = 0;
uint16_t ir_data = 0;
float illuminance = 0;
// Enable and wait for proximity interrupt
ambient14_write_reg ( &ambient14, AMBIENT14_REG_INTENAB, AMBIENT14_INTENAB_PIEN );
while ( ambient14_get_int_pin ( &ambient14 ) );
// Read proximity data and clear interrupts
if ( AMBIENT14_OK == ambient14_read_proximity ( &ambient14, &proximity ) )
{
log_printf ( &logger, " Proximity: %u\r\n", proximity );
}
ambient14_clear_interrupts ( &ambient14 );
// Enable and wait for ALS interrupt
ambient14_write_reg ( &ambient14, AMBIENT14_REG_INTENAB, AMBIENT14_INTENAB_AIEN );
while ( ambient14_get_int_pin ( &ambient14 ) );
// Read ALS and IR data counts, calculates illuminance level, and clear interrupts
if ( AMBIENT14_OK == ambient14_read_als_ir ( &ambient14, &als_data, &ir_data ) )
{
log_printf ( &logger, " ALS: %u\r\n", als_data );
log_printf ( &logger, " IR: %u\r\n", ir_data );
if ( AMBIENT14_OK == ambient14_get_illuminance ( &ambient14, als_data, &illuminance ) )
{
log_printf ( &logger, " Illuminance: %.1f Lux\r\n\n", illuminance );
}
}
ambient14_clear_interrupts ( &ambient14 );
}
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
