136 lines
6.2 KiB
Plaintext
136 lines
6.2 KiB
Plaintext
/**
|
|
@page UART_TwoBoards_ComDMA UART Two Boards Communication DMA example
|
|
|
|
@verbatim
|
|
******************************************************************************
|
|
* @file UART/UART_TwoBoards_ComDMA/readme.txt
|
|
* @author MCD Application Team
|
|
* @brief Description of the UART Two Boards Communication DMA example.
|
|
******************************************************************************
|
|
*
|
|
* Copyright (c) 2020 STMicroelectronics. All rights reserved.
|
|
*
|
|
* This software component is licensed by ST under BSD 3-Clause license,
|
|
* the "License"; You may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at:
|
|
* opensource.org/licenses/BSD-3-Clause
|
|
*
|
|
******************************************************************************
|
|
@endverbatim
|
|
|
|
@par Example Description
|
|
|
|
UART transmission (transmit/receive) in DMA mode
|
|
between two boards.
|
|
|
|
Board: NUCLEO-WL55JC RevC (embeds a STM32WL55JCIx device)
|
|
Tx Pin: PB.06 (Arduino connector CN9 pin 2)
|
|
Rx Pin: PB.07 (Arduino connector CN9 pin 1)
|
|
_________________________ _________________________
|
|
| ______________| |______________ |
|
|
| |USART | | USART| |
|
|
| | | | | |
|
|
| | TX |_____________________| RX | |
|
|
| | | | | |
|
|
| | | | | |
|
|
| | | | | |
|
|
| | RX |_____________________| TX | |
|
|
| | | | | |
|
|
| |______________| |______________| |
|
|
| | | |
|
|
| GND|_____________________|GND |
|
|
|_STM32_Board 1___________| |_STM32_Board 2___________|
|
|
|
|
|
|
|
|
Two identical boards are connected as shown on the picture above.
|
|
Board 1: transmitting then receiving board
|
|
Board 2: receiving then transmitting board
|
|
|
|
The user presses the User push-button (B1) on board 1.
|
|
Then, board 1 sends in DMA mode a message to board 2 that sends it back to
|
|
board 1 in DMA mode as well.
|
|
Finally, board 1 and 2 compare the received message to that sent.
|
|
If the messages are the same, the test passes.
|
|
|
|
|
|
WARNING: as both boards do not behave the same way, "TRANSMITTER_BOARD" compilation
|
|
switch is defined in /Src/main.c and must be enabled
|
|
at compilation time before loading the executable in the board that first transmits
|
|
then receives.
|
|
The receiving then transmitting board needs to be loaded with an executable
|
|
software obtained with TRANSMITTER_BOARD disabled.
|
|
|
|
NUCLEO-WL55JC RevC board LEDs are used to monitor the transfer status:
|
|
- While board 1 is waiting for the user to press the User push-button (B1), its LED1 is
|
|
blinking rapidly (100 ms period).
|
|
- While board 2 is waiting for the message from board 1, its LED1 is emitting
|
|
a couple of flashes every half-second.
|
|
- When the test passes, LED1 is turned on.
|
|
- If there is an initialization or transfer error, LED3 is turned on.
|
|
|
|
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 48 MHz.
|
|
|
|
|
|
The UART is configured as follows:
|
|
- BaudRate = 9600 baud
|
|
- Word Length = 8 bits (8 data bits, no parity bit)
|
|
- One Stop Bit
|
|
- No parity
|
|
- Hardware flow control disabled (RTS and CTS signals)
|
|
- Reception and transmission are enabled in the time
|
|
|
|
@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 needs to ensure that the SysTick time base is always set to 1 millisecond
|
|
to have correct HAL operation.
|
|
|
|
@par Keywords
|
|
|
|
Connectivity, UART/USART, baud rate, RS-232, full-duplex, DMA, parity, stop bit,
|
|
Transmitter, Receiver, Asynchronous
|
|
|
|
@par Directory contents
|
|
|
|
- UART/UART_TwoBoards_ComDMA/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
|
|
- UART/UART_TwoBoards_ComDMA/Inc/stm32wlxx_hal_conf.h HAL configuration file
|
|
- UART/UART_TwoBoards_ComDMA/Inc/stm32wlxx_it.h DMA interrupt handlers header file
|
|
- UART/UART_TwoBoards_ComDMA/Inc/main.h Header for main.c module
|
|
- UART/UART_TwoBoards_ComDMA/Src/stm32wlxx_it.c DMA interrupt handlers
|
|
- UART/UART_TwoBoards_ComDMA/Src/main.c Main program
|
|
- UART/UART_TwoBoards_ComDMA/Src/stm32wlxx_hal_msp.c HAL MSP module
|
|
- UART/UART_TwoBoards_ComDMA/Src/system_stm32wlxx.c STM32WLxx system source file
|
|
|
|
|
|
@par Hardware and Software environment
|
|
|
|
- This example runs on STM32WL55JCIx devices.
|
|
- This example has been tested with two NUCLEO-WL55JC RevC boards embedding
|
|
a STM32WL55JCIx device and can be easily tailored to any other supported device
|
|
and development board.
|
|
|
|
- NUCLEO-WL55JC RevC set-up
|
|
- Connect a wire between 1st board PB6 pin (Uart Tx) and 2nd board PB7 pin (Uart Rx)
|
|
- Connect a wire between 1st board PB7 pin (Uart Rx) and 2nd board PB6 pin (Uart Tx)
|
|
- Connect 1st board GND to 2nd Board GND
|
|
|
|
@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
|
|
|
|
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
|
|
*/
|