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Example description

RTC_Calendar

Example Description

This example demonstrates and explains how to use the RTC peripheral.
As an application example, it demonstrates how to setup the RTC peripheral, in terms
of prescaler and interrupts, to be used to keep time and to generate Second interrupt.

The Low Speed External (LSE) clock is used as RTC clock source.
The RTC clock can be output on the Tamper pin (PC.13). To enable this functionality,
uncomment the corresponding line: #define RTCClockOutput_Enable in the main.c file.

The RTC is in the backup (BKP) domain, still powered by VBAT when VDD is switched off,
so the RTC configuration is not lost if a battery is connected to the VBAT pin.
A key value is written in backup data register1 (BKP_DR1) to indicate if the RTC
is already configured.

The program behaves as follows:

1. After startup the program checks the backup data register1 value:
- register1 value not correct: (BKP_DR1 value is not correct or has not yet
been programmed when the program is executed for the first time) the RTC is
configured and the user is asked to set the time (entered on HyperTerminal).

- register1 value correct: this means that the RTC is configured and the time
is displayed on HyperTerminal.

2. When an External Reset occurs the BKP domain is not reset and the RTC configuration
is not lost.

3. When power on reset occurs:
- If a battery is connected to the VBAT pin: the BKP domain is not reset and
the RTC configuration is not lost.

- If no battery is connected to the VBAT pin: the BKP domain is reset and the
RTC configuration is lost.

In the RTC interrupt service routine, the LED1 toggles every 1 s.
The C library printf function is retargeted to the USART, that is, the printf
message is output to the HyperTerminal using USART1 or USART2 depending on the
EVAL board you are using.

Directory contents

- RTC/Calendar/stm32f10x_conf.h Library Configuration file
- RTC/Calendar/stm32f10x_it.c Interrupt handlers
- RTC/Calendar/stm32f10x_it.h Header for stm32f10x_it.c
- RTC/Calendar/main.c Main program

Hardware and Software environment

- This example runs on STM32F10x Connectivity line, High-Density, Medium-Density
and Low-Density Devices.

- This example has been tested with STMicroelectronics STM3210C-EVAL (STM32F10x
Connectivity line), STM3210E-EVAL (STM32F10x High-Density) and STM3210B-EVAL
(STM32F10x Medium-Density) evaluation boards and can be easily tailored to
any other supported device and development board.
To select the STMicroelectronics evaluation board used to run the example,
uncomment the corresponding line in stm32_eval.h file (under Utilities\STM32_EVAL)

- STM3210C-EVAL Set-up
- Use LED1 connected to PD.07.
- Connect a null-modem female/female RS232 cable between the DB9 connector
CN6 (USART2) and PC serial port .
note Make sure that jumpers JP19 and JP18 are open.
- Make sure that jumper JP24 is in position 1-2 to connect the 3V battery to VBAT pin

- STM3210E-EVAL Set-up
- Use LED1 connected to PF.06.
- Connect a null-modem female/female RS232 cable between the DB9 connector
CN12(when USART1 is used) and PC serial port.
- Make sure that jumper JP1 is in position 1-2 to connect the 3V battery to VBAT pin

- STM3210B-EVAL Set-up
- Use LED1 connected to PC.06.
- Connect a null-modem female/female RS232 cable between the DB9 connector
CN6(when USART1 is used) and PC serial port.
- Make sure that jumper JP11 is in position 1-2 to connect the 3V battery to VBAT pin

- Hyperterminal configuration:
- Word Length = 8 Bits
- One Stop Bit
- No parity
- BaudRate = 115200 baud
- flow control: None

How to use it ?

In order to make the program work, you must do the following :
- Create a project and setup all project configuration
- Add the required Library files :
- stm32f10x_gpio.c
- stm32f10x_rcc.c
- stm32f10x_rtc.c
- stm32f10x_bkp.c
- stm32f10x_pwr.c
- misc.c
- stm32f10x_usart.c
- stm32f10x_exti.c
- system_stm32f10x.c (under Libraries\CMSIS\Core\CM3)
- stm32_eval.c (under Utilities\STM32_EVAL)

- Edit stm32f10x.h file to select the device you are working on.
- Edit stm32_eval.h file to select the evaluation board you will use.

Tip: You can tailor the provided project template to run this example, for
more details please refer to "stm32f10x_stdperiph_lib_um.chm" user
manual; select "Peripheral Examples" then follow the instructions
provided in "How to proceed" section.
- Link all compiled files and load your image into target memory
- Run the example

note
- Low-density devices are STM32F101xx and STM32F103xx microcontrollers where
the Flash memory density ranges between 16 and 32 Kbytes.
- Medium-density devices are STM32F101xx and STM32F103xx microcontrollers where
the Flash memory density ranges between 32 and 128 Kbytes.
- High-density devices are STM32F101xx and STM32F103xx microcontrollers where
the Flash memory density ranges between 256 and 512 Kbytes.
- Connectivity line devices are STM32F105xx and STM32F107xx microcontrollers.

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RTC_LSI_Calib

Example Description

This example demonstrates and explains how to use the LSI clock source auto
calibration to get a precise RTC clock.
As an application example, it demonstrates how to configure the TIM5 timer
internally connected to LSI clock output, in order to adjust the RTC prescaler.

The Low Speed External (LSI) clock is used as RTC clock source.
After reset, the RTC prescaler is set with the default value (40000).
The inaccuracy of the LSI clock causes the RTC Second signal to be inaccurate. This
signal is output on the Tamper pin (PC.13) and can be measured by on oscilloscope
or a frequencymeter.

The program waits until Key Push button is pressed to begin the auto calibration procedure:
- Configure the TIM5 to remap internally the TIM5 Channel 4 Input Capture to the
LSI clock output.
- Enable the TIM5 Input Capture interrupt: after one cycle of LSI clock, the
period value is stored in a variable and compared to the HCLK clock to get
its real value.
- The RTC prescaler is adjusted with this LSI frequency value so that the RTC
Second value become more accurate.
- When calibration is done a led connected to PF.07 is turned ON to indicate the
end of this operation. At this moment, you can monitor the Second signal on
an oscilloscope to measure its accuracy again.

The RTC Second signal can be monitored either on Tamper pin or on LED1 which is
toggled into the RTC Second interrupt service routine.

Directory contents

- RTC/LSI_Calib/stm32f10x_conf.h Library Configuration file
- RTC/LSI_Calib/stm32f10x_it.c Interrupt handlers
- RTC/LSI_Calib/stm32f10x_it.h Header for stm32f10x_it.c
- RTC/LSI_Calib/main.h Main header file
- RTC/LSI_Calib/main.c Main program

Hardware and Software environment

- This example runs on STM32F10x Connectivity line and High-Density Devices.

- This example has been tested with STMicroelectronics STM3210C-EVAL (STM32F10x
Connectivity line) and STM3210E-EVAL (STM32F10x High-Density)evaluation boards
and can be easily tailored to any other supported device and development board.
To select the STMicroelectronics evaluation board used to run the example,
uncomment the corresponding line in stm32_eval.h file (under Utilities\STM32_EVAL)

- STM3210C-EVAL Set-up
- Use LD1 and LD2 leds connected respectively to PD.07 and PD.13 pins
- Use the Key push-button connected to PB.09 pin

- STM3210E-EVAL Set-up
- Use LD1 and LD2 leds connected respectively to PF.06 and PF.07 pins
- Use the Key push button connected to PG.08 pin

How to use it ?

In order to make the program work, you must do the following :
- Create a project and setup all project configuration
- Add the required Library files :
- stm32f10x_gpio.c
- stm32f10x_rcc.c
- stm32f10x_rtc.c
- stm32f10x_tim.c
- stm32f10x_bkp.c
- stm32f10x_pwr.c
- misc.c
- stm32f10x_usart.c
- system_stm32f10x.c (under Libraries\CMSIS\Core\CM3)
- stm32_eval.c (under Utilities\STM32_EVAL)

- Edit stm32f10x.h file to select the device you are working on.
- Edit stm32_eval.h file to select the evaluation board you will use.