Master temperature control with TMP235 and STM32F091RC
Maintain the ideal temperature
Published Feb 26, 2024
Click board™
Heater Click
Dev. board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Keep your specified temperature range under control with our invaluable tool for projects and products with critical thermal requirements.
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Hardware Overview
How does it work?
Heater Click is based on the TMP235, an onboard temperature sensor from Texas Instruments. It is designed with intention of PCB heater concept testing and useful tool for heating complete casing where staying in specified temperature range is crucial. Heater Click works on a principle of Joule heating, also known as resistance heating (resistive heating), a process by which the passage of an electric current thrrough a conductor produces heat. Energy dissipated per unit time is equall to current passing through resistor times electric potential difference. Heater Click allows PCB temperature adjusting and monitoring as it have embedded trace resistor on top layer of PCB. Resistor is made from copper 1oz thick and a pattern of 0.1mm wide track 1950mm long, this give us about 10 ohm resistance
at 25 degrees Celsius. With on bord VIN SEL jumper power supply can be selected as 5V from mikroBUS or any other voltage from external power supply at therminal block VIN. Using mikroBUS PWM pin power dissipation can be adjusted and therfore temperature controlled. Heater Click minimize temperature spread from embedded resistor by having PCB gaps between it and rest of the click bord and components, by doing so hot zone is easier to warm up and keeping it at exact temperature without affecting rest of the commponents. LEDs are connected to LD1 and LD2 GPIO pins and can be used for example to signal user if temperature is ramping up or achieved, or any other user defined signaling. Since the temperature rise in a heater is a function of its resistance and voltage, you don’t always
need to design a heater from scratch. So long as you can apply a specific voltage, you should be able to achieve your desired temperature and monitoring it through I2C. Temperature is monitored with TMP235 precision CMOS integrated-circuit linear analog temperature sensor with an output voltage proportional to temperature, The TMP235 device provides a positive slope output of 10 mV/°C over the full –40°C to +150°C temperature range. Using MCP3221 a 12-bit ADC, output voltage from temperature sensor can be red through I2C. Communication to the MCP3221 is performed using a 2-wire, I2C compatible interface. Standard (100 kHz) and Fast (400 kHz) I2C modes are available with the device.
Features overview
Development board
Nucleo-64 with STM32F091RC 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)
256
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
32768
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 STM32F091RC 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 Heater Click driver.
Key functions:
heater_read_data- This function writes data to the desired register.heater_read_mv- Read data in mVheater_read_temp- Read data in C
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
* \brief heater Click example
*
* # Description
* The devices resolution depends on settings applied.
* User should consult the datasheet and choose resolution value
* that corresponds to the settings applied.
*
* ## Application Init
* Initialization of PWM module and start heating up
*
* ## Application Task
* Durning the task device is heating up to 50 degree C and then
* cooling down to 40 degree C
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "heater.h"
// ------------------------------------------------------------------ VARIABLES
static heater_t heater;
static log_t logger;
static float temp_read;
static uint8_t status_dev;
static float duty_cycle_heating = 0.5;
static float duty_cycle_cooling = 0.0;
const float HOT_TEMP = 50.0;
const float COOL_TEMP = 40.0;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
heater_cfg_t cfg;
heater_config_t cfg1;
/**
* 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.
heater_cfg_setup( &cfg, &cfg1 );
HEATER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
heater_init( &heater, &cfg, &cfg1 );
heater_set_duty_cycle( &heater, duty_cycle_heating );
heater_pwm_start( &heater );
log_printf( &logger, " ***** APP INIT ***** \r\n" );
Delay_ms ( 500 );
}
void application_task ( void )
{
temp_read = heater_read_temp( &heater );
if ( temp_read > HOT_TEMP )
{
heater_set_duty_cycle( &heater, duty_cycle_cooling );
heater_set_led1_status( &heater, HEATER_LED_OFF );
heater_set_led2_status( &heater, HEATER_LED_ON );
log_printf( &logger, " - Cooling off -\r\n" );
}
else if ( temp_read < COOL_TEMP )
{
heater_set_duty_cycle( &heater, duty_cycle_heating );
heater_set_led1_status( &heater, HEATER_LED_ON );
heater_set_led2_status( &heater, HEATER_LED_OFF );
log_printf( &logger, " - Heating up -\r\n" );
}
log_printf( &logger, " - Temperature: %.2f degC\r\n", temp_read );
log_printf( &logger, "***************\r\n" );
Delay_ms ( 1000 );
}
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
