This Example shows a UART transmission (transmit/receive) between 2
STM32L053R8-Nucleo boards in interrupt mode.這個例子展示了串口的中斷收發模式。
At the beginning of the main program the HAL_Init() function is called to reset
all the peripherals, initialize the Flash interface and the systick.
Then the SystemClock_Config() function is used to configure the system
clock (SYSCLK) to run at 32 MHz.
一開始的主程序通過這個函數來復位所有外設，初始化flash系統滴答接口，為了滴答用可能跟flash有關。
Then 1st board is waiting for user button key to be pressed. Once done, data
are transmitted through uart2 in IT mode. 2nd board has configured Uart2
to receive data in IT mode. Once data received is completed, 2nd board also
transmit same characters on uart1 which will be received by 1st board.
Both boards compare transmitted data to received ones. If they are same, green
led2 is turn on, else led2 is turn Off.
第一塊板子等待按鍵按下后，數據發送給第二個板子，這里是IT模式，第二塊板子通過串口中斷接收到數據后，再將該數據發送給第一塊板子。如果數據
一樣綠燈亮。
Warning: As both boards do not behave same way, "TRANSMITTER_BOARD" switch
compilation exists to determine either software is for 1st transmitter board or
2nd receiver (then transmitter) board. In other words, 1st board has to be
flashed with software compiled with switch enable, 2nd board has to be flashed
with software compiled with switch disable.
LED2 can be used to monitor the transfer status:
- LED2 turns ON on master board waiting user button to be pressed.
- LED2 turns OFF on master board waiting the transmission process is complete.
- LED2 turns ON when the transmission/reception process is correct.
The UART is configured as follow:
- BaudRate = 9600 baud
- Word Length = 8 Bits (7 data bit + 1 parity bit)
- One Stop Bit
- None parity
- Hardware flow control disabled (RTS and CTS signals)
- Reception and transmission are enabled in the time
@note USARTx/UARTx instance used and associated resources can be updated in "main.h"
file depending hardware configuration used.
@note When the parity is enabled, the computed parity is inserted at the MSB
position of the transmitted data.
@note Care must be taken when using HAL_Delay(), this function provides accurate
delay (in milliseconds) based on variable incremented in SysTick ISR. This
implies that if HAL_Delay() is called from a peripheral ISR process, then
the SysTick interrupt must have higher priority (numerically lower)
than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
@note The application need to ensure that the SysTick time base is always set to 1 millisecond
to have correct HAL operation.
@par Directory contents
- UART/UART_TwoBoards_ComIT/Inc/stm32l0xx_hal_conf.h HAL configuration file
- UART/UART_TwoBoards_ComIT/Inc/stm32l0xx_it.h IT interrupt handlers header file
- UART/UART_TwoBoards_ComIT/Inc/main.h Header for main.c module
- UART/UART_TwoBoards_ComIT/Src/stm32l0xx_it.c IT interrupt handlers
- UART/UART_TwoBoards_ComIT/Src/main.c Main program
- UART/UART_TwoBoards_ComIT/Src/stm32l0xx_hal_msp.c HAL MSP module
- UART/UART_TwoBoards_ComIT/Src/system_stm32l0xx.c STM32L0xx system source file
@par Hardware and Software environment
- This example runs on STM32L051xx, STM32L052xx, STM32L053xx STM32L062xx and
STM32L063xx device lines RevZ
- This example has been tested with STM32L053R8-Nucleo RevC and can be
easily tailored to any other supported device and development board.
- STM32L053R8-Nucleo RevC Set-up
- Connect a wire between 1st board PA9 (pin 21 in CN10 connector) pin (Uart Tx)
to 2nd board PA10 (pin 33 in CN10 connector) pin (Uart Rx)
- Connect a wire between 1st board PA10 (pin 33 in CN10 connector) pin (Uart Rx)
to 2nd board PA9 (pin 21 in CN10 connector) pin (Uart Tx)
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example