Example description
RCC_Example RCC example
Example Description
This example shows how to use, for debug purpose, the RCC_GetClocksFreq function
to retrieve the current status and frequencies of different on chip clocks.
You can see the RCC_ClockFreq structure content, which hold the frequencies of
different on chip clocks, using your toolchain debugger.
This example handles also the High Speed External clock (HSE) failure detection:
when the HSE clock disappears (broken or disconnected external Quartz); HSE, PLL
are disabled (but no change on PLL config), HSI selected as system clock source
and an interrupt (NMI) is generated. In the NMI ISR, the HSE, HSE ready interrupt
are enabled and once HSE clock recover, the HSERDY interrupt is generated and in
the RCC ISR routine the system clock is reconfigured to its previous state (before
HSE clock failure). You can monitor the HSE clock on MCO1 pin(PA8).
Four LEDs are toggled with a timing defined by the Delay function.
On the STM322xG-EVAL board, to genertate the HSE failure you can remove
the HSE quartz from the socket.
Directory contents
- RCC/RCC_Example/system_stm32f2xx.c STM32F2xx system clock configuration file
- RCC/RCC_Example/stm32f2xx_conf.h Library Configuration file
- RCC/RCC_Example/stm32f2xx_it.c Interrupt handlers
- RCC/RCC_Example/stm32f2xx_it.h Interrupt handlers header file
- RCC/RCC_Example/main.c Main program
The "system_stm32f2xx.c" is generated by an automatic clock configuration
tool and can be easily customized to your own configuration.
To select different clock setup, use the "STM32F2xx_Clock_Configuration_V1.0.0.xls" tool.
Hardware and Software environment
- This example runs on STM32F2xx Devices.
- This example has been tested with STM322xG-EVAL RevB and can be easily
tailored to any other development board.
- STM322xG-EVAL Set-up
- Use LED1, LED2, LED3 and LED4 connected respectively to PG.06, PG.08, PI.09
and PC.07 pins