Stay on schedule with MCP79410 and STM32F207VGT6
Mastering time: The unseen wonders of RTC
Published Oct 20, 2023
Click board™
RTC 6 Click
Dev. board
EasyMx PRO v7a for STM32
Compiler
NECTO Studio
MCU
STM32F207VGT6
Take control of time synchronization in your projects with advanced real-time clock, delivering reliable and precise timing accuracy
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Hardware Overview
How does it work?
RTC 6 Click is based on the MCP79411, a battery-backed I2C real-time clock/calendar with SRAM, and protected EEPROM from Microchip. The alarms on this RTC 6 Click can be configured on all counters up to and including months. The clock frequency is delivered from an onboard 32.768KHz crystal oscillator. On-chip digital trimming with ±1 ppm resolution and ±129 ppm range can be used to adjust for frequency variance caused by crystal tolerance and temperature. For backup power for the RTC, this Click board™ features the coin-cell Lithium battery holder that supports CR1216, CR1220, and CR1225 battery formats. By removing the 0ohm resistor, you can turn off battery backup. For storing data, the MCP79411 has 64 bytes of battery-backed SRAM that correlate with the
timekeeping circuit and allow the device to maintain accurate time and date when main power is lost. The time between power switches, from backup to primary power and vice versa, is restored is recorded by the power outage time stamp. The MCP79411 features 1Kbit of internal nonvolatile EEPROM with software write protectable regions. An additional 64 bits of protected nonvolatile memory is only writable after an unlock sequence, making it ideal for storing a unique ID or other critical information. The RTC 6 Click uses an I2C interface for communication with the host MCU, with a clock rate of up to 400kHz. This Click board™ also features a multifunction pin, accessible over the MFP pin of the mikroBUS™ socket. The
multifunctional output on this pin can be configured to assert an alarm match to output a selectable frequency square wave or as a general-purpose output. The MCP79411 features two independent alarms. Each alarm can generate either an interrupt at a specific time in the future or a periodic interrupt every minute, hour, day, day of week, or month. 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
EasyMx PRO v7a for STM32 is the seventh generation of ARM development boards specially designed to develop embedded applications rapidly. It supports a wide range of 32-bit ARM microcontrollers from STMicroelectronics and a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. With two different connectors for each port, EasyMx PRO v7afor STM32 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyMx
PRO v7a for STM32 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART, USB-HOST/DEVICE, CAN, and
Ethernet are also included, including the well-established mikroBUS™ standard, one display option for the TFT board line of products, and a standard TQFP socket for the seventh-generation MCU cards. This socket covers 32-bit ARM MCUs like STM32 Cortex-M3, -M7, and -M4 MCUs. EasyMx PRO v7afor STM32 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Type
7th Generation
Architecture
ARM Cortex-M3
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
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 EasyMx PRO v7a for STM32 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 6 Click driver.
Key functions:
rtc6_battery_enable- This function enables automatic switch to battery on VCC failurertc6_get_gmt_time- This function gets current GMT time and sets it in the RTCrtc6_get_local_time- This function calculates current local time
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 Rtc6 Click example
*
* # Description
* This application enables usage of Real-TIme clock and calendar with alarm on RTC 6 click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes driver init, sets time zone, sets UTC-GMT time and alarm time
*
* ## Application Task
* Reads GMT time and Local time. Checks if the alarm is activated.
* If the alarm is active, it disable alarm and adjusts the new one within 20 seconds.
* Logs this data on USBUART every 900ms.
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "rtc6.h"
// ------------------------------------------------------------------ VARIABLES
static rtc6_t rtc6;
static log_t logger;
static rtc6_time_t utc_time;
static rtc6_time_t alarm_time;
static rtc6_time_t local_time;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
rtc6_cfg_t cfg;
int8_t time_zone = 2;
/**
* 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.
rtc6_cfg_setup( &cfg );
RTC6_MAP_MIKROBUS( cfg, MIKROBUS_1 );
rtc6_init( &rtc6, &cfg );
// Set UTC time
utc_time.seconds = 40;
utc_time.minutes = 59;
utc_time.hours = 23;
utc_time.monthday = 14;
utc_time.month = 12;
utc_time.year = 18;
// Set alarm time
alarm_time.seconds = 0;
alarm_time.minutes = 0;
alarm_time.hours = 0;
alarm_time.weekdays = 0;
alarm_time.monthday = 15;
alarm_time.month = 12;
alarm_time.year = 18;
rtc6_default_cfg( &rtc6, time_zone, &utc_time, &alarm_time );
log_info( &logger, " ----- Init successfully ----- " );
Delay_ms( 2000 );
}
void application_task ( void )
{
// Task implementation.
rtc6_get_gmt_time( &rtc6, &utc_time );
rtc6_get_local_time( &rtc6, &local_time );
log_printf( &logger, "--- UTC time ---\r\nTime : %u %u %u\r\n", ( uint16_t )utc_time.hours, ( uint16_t )utc_time.minutes, ( uint16_t )utc_time.seconds );
log_printf( &logger, "Date : %u %u %u\r\n", ( uint16_t )utc_time.monthday, ( uint16_t )utc_time.month, utc_time.year );
log_printf( &logger, "--- Local time ---\r\nTime : %u %u %u\r\n", ( uint16_t )local_time.hours, ( uint16_t )local_time.minutes, ( uint16_t )local_time.seconds );
log_printf( &logger, "Date : %u %u %u\r\n \r\n", ( uint16_t )local_time.monthday, ( uint16_t )local_time.month, local_time.year );
if ( rtc6_is_active_alarm( &rtc6 ) != 0 )
{
log_printf( &logger, " ----- Active alarm ----- \r\n" );
rtc6_disable_alarm( &rtc6, RTC6_ALARM_0 );
rtc6_repeat_alarm( &rtc6, RTC6_ALARM_0, 20 );
}
Delay_ms( 900 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
