Transform your time management with MAX31341B and STM32F091RC
Tick-tock, seize the day
Published Feb 26, 2024
Click board™
RTC 7 Click
Dev. board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Experience the power of precise timekeeping in your engineering projects by integrating state-of-the-art real-time clock solution
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Hardware Overview
How does it work?
RTC 7 Click is based on the MAX31341B, a low-current Real-Time Clock with I2C interface and power management from Analog Devices. Thanks to its high integration level, this module provides high time accuracy, with a very low count of external components required. It has a full RTC function, offering programmable counters, alarms, and an interrupt engine with selectable event reporting sources. The small dimension of the MAX31341B module itself, allow it to be used in very space-constrained applications, including wearables, medical equipment, and similar. In addition to the MAX31341B, RTC 7 click is equipped with the 220mF super capacitor. By utilizing an automatic backup switch, the IC is able to use an external battery power source when there is no power supply on its main power terminals, thus allowing for uninterrupted operation. Draining as low as 180nA of current, it can be operated with the mentioned supercapacitor almost indefinitely.
In addition, a trickle charge system will replenish the super capacitor while the MAX31341B is powered over the main power terminals (VDD, VSS). The voltage of the main power supply can range between 1.6V up to 3.6V. The MAX31341B uses the I2C communication protocol for the communication with the host MCU. Besides the I2C bus lines, two additional pins are also available on the MAX31341B, INTA and INTB, allowing an interrupt to be reported to the host MCU, but also to capture an external event and marking it with an automatic timestamp. The two mentioned interrupt pins are routed to INT and AN pins of the mikroBUS™ socket, respectively. The user is able to set up standard clock and calendar functions (including seconds, minutes, hours, weekdays, date, months, years with leap year correction), as well as the interrupt functions for the periodic countdown timer, periodic time update, alarm, external event, automatic backup switchover and
power on reset (POR) events. All these features are available when the module is operated over the backup power supply (battery). Besides other functions, RTC 7 click have one analog and one digitital external input, labeled AIN and DIN. These universal inputs can be wired to any kind of external trigger, which needs to trigger one of the interrupts. The digital input can be configured to detect rising or falling edge, while the analog input, besides the edge detection, supports the programmable threshold too. For detailed information on interrupts and external triggers, refer to the MAX31341B datasheet. 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 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 RTC 7 Click driver.
Key functions:
rtc7_check_interrupt- This function returns the interrupt state, state of INTA pinrtc7_read_reg- This function writes one byte data to the registerrtc7_get_local_time- This function gets the local time data including the determined time zone in calculations
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 RTC7 Click example
*
* # Description
* This app is used to accurately measure time with low power consumption.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes device.
*
* ## Application Task
* Waits for a second count-up interrupt and then reads and logs the current
* time and date on the USB UART.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "rtc7.h"
// ------------------------------------------------------------------ VARIABLES
static rtc7_t rtc7;
static log_t logger;
rtc7_time_t time_set;
rtc7_time_t time_date;
// ------------------------------------------------------- ADDITIONAL FUNCTIONS
void rtc7_display_results ( rtc7_t *ctx )
{
log_printf( &logger, " %.2u:%.2u:%.2u\r\n",
( uint16_t ) time_date.hours, ( uint16_t ) time_date.minutes, ( uint16_t ) time_date.seconds );
log_printf( &logger, " %.2u/%.2u/%.2u ",
( uint16_t ) time_date.monthday, ( uint16_t ) time_date.month, ( uint16_t ) time_date.year );
switch ( time_date.weekdays )
{
case 1:
{
log_printf( &logger, "MONDAY" );
break;
}
case 2:
{
log_printf( &logger, "TUESDAY" );
break;
}
case 3:
{
log_printf( &logger, "WEDNESDAY" );
break;
}
case 4:
{
log_printf( &logger, "THURSDAY" );
break;
}
case 5:
{
log_printf( &logger, "FRIDAY" );
break;
}
case 6:
{
log_printf( &logger, "SATURDAY" );
break;
}
case 7:
{
log_printf( &logger, "SUNDAY" );
break;
}
default:
{
break;
}
}
log_printf( &logger, "\r\n-------------------\r\n" );
}
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
rtc7_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.
rtc7_cfg_setup( &cfg );
RTC7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
rtc7_init( &rtc7, &cfg );
Delay_ms ( 300 );
time_set.seconds = 40;
time_set.minutes = 59;
time_set.hours = 23;
time_set.weekdays = 1;
time_set.monthday = 31;
time_set.month = 12;
time_set.year = 22;
err_t error_flag = rtc7_reset( &rtc7 );
error_flag |= rtc7_init_time ( &rtc7, 0 );
error_flag |= rtc7_set_gmt_time( &rtc7, &time_set );
error_flag |= rtc7_set_osc( &rtc7, RTC7_ENABLE_OSC, RTC7_INPUT_FREQ_32768HZ, RTC7_OUTPUT_FREQ_32768HZ );
error_flag |= rtc7_write_reg( &rtc7, RTC7_TIMER_INIT_REG, 15 );
error_flag |= rtc7_set_timer( &rtc7, RTC7_TIMER_EN, RTC7_TIMER_FREQ_16HZ );
Delay_ms ( 100 );
if ( RTC7_ERROR == error_flag )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
// Wait for timer count-down interrupt which is set to 1Hz
while ( rtc7_check_interrupt ( &rtc7 ) );
// Clear interrupt status
uint8_t int_status = 0;
rtc7_read_reg( &rtc7, RTC7_INT_STATUS_REG, &int_status, 1 );
// Read time
if ( RTC7_OK == rtc7_get_local_time( &rtc7, &time_date ) )
{
// Display time
rtc7_display_results( &rtc7 );
}
}
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
