/**
@page UART_TwoBoards_ComIT UART Two Boards Communication IT example
@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file UART/UART_TwoBoards_ComIT/readme.txt
* @author MCD Application Team
* @brief Description of the UART Two Boards Communication IT example.
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
This example describes an UART transmission (transmit/receive) in interrupt mode
between two boards.
Board: STM32469I-DISCOVERY (embeds a STM32469I device)
Tx Pin: PC6 (pin6 in CN12 connector)
Rx Pin: PC7 (pin8 in CN12 connector)
_________________________ _________________________
| ______________| |______________ |
| |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 on board 1.
Then, board 1 sends in interrupt mode a message to board 2 that sends it back to
board 1 in interrupt 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.
STM32469I-DISCOVERY board LEDs are used to monitor the transfer status:
- While board 1 is waiting for the user to press the User push-button, its LED2 is
blinking rapidly (100 ms period).
- While board 2 is waiting for the message from board 1, its LED2 is emitting
a couple of flashes every half-second.
- When the test passes, LED3 and LED1 on both boards are both turned on:
* LED1 is ON when the transmission process is complete.
* LED3 is ON when the reception process is complete.
If LED3 and LED1 are not both turned on, the test has failed.
- If there is an initialization or transfer error, LED4 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 180 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 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.
@note The connection of the LCD reset pin to a dedicated GPIO PH7 instead of the STM32F469 NRST pin may cause residual display on LCD with applications/examples that do not require display.
The LCD clear can be ensured by hardware through the boards power off/power on or by software calling the BSP_LCD_Reset() function.
@par Keywords
Connectivity, UART, Baud rate, RS-232, Full-duplex, Interrupt, Parity, Stop bit, Transmission, Reception
@par Directory contents
- UART/UART_TwoBoards_ComIT/Inc/stm32f4xx_hal_conf.h HAL configuration file
- UART/UART_TwoBoards_ComIT/Inc/stm32f4xx_it.h IT interrupt handlers header file
- UART/UART_TwoBoards_ComIT/Inc/main.h Header for main.c module
- UART/UART_TwoBoards_ComIT/Src/stm32f4xx_it.c IT interrupt handlers
- UART/UART_TwoBoards_ComIT/Src/main.c Main program
- UART/UART_TwoBoards_ComIT/Src/stm32f4xx_hal_msp.c HAL MSP module
- UART/UART_TwoBoards_ComIT/Src/system_stm32f4xx.c STM32F4xx system source file
@par Hardware and Software environment
- This example runs on STM32F469xx devices.
- This example has been tested with two STM32469I-DISCOVERY boards embedding
a STM32469I device and can be easily tailored to any other supported device
and development board.
- STM32469I-DISCOVERY set-up
- Connect a wire between 1st board PC6 pin (Uart Tx) and 2nd board PC7 pin (Uart Rx)
- Connect a wire between 1st board PC7 pin (Uart Rx) and 2nd board PC6 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
*/
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