159 lines
7.1 KiB
Plaintext
159 lines
7.1 KiB
Plaintext
/**
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@page UART_HyperTerminal_DMA UART Hyperterminal DMA Example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file UART/UART_HyperTerminal_DMA/readme.txt
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* @author MCD Application Team
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* @brief Description of the UART Hyperterminal example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2017 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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This example describes an UART transmission (transmit/receive) in DMA mode
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between a board and an Hyperterminal PC application.
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Board: STM32446E-EVAL
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Tx Pin: PA.09
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Rx Pin: PA.10
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_________________________
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| ______________| _______________
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| |USART | | HyperTerminal |
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| | | | |
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| | TX |______________________|RX |
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| | | | |
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| | | RS232 Cable | |
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| | | | |
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| | RX |______________________|TX |
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| | | | |
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| |______________| |_______________|
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|_STM32_Board_____________|
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This example guides you through the different configuration steps by mean of HAL API
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to ensure UART Data buffer transmission and reception with DMA.
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The communication is done with the Hyperterminal PC application.
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At the beginning of the main program the HAL_Init() function is called to reset
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all the peripherals, initialize the Flash interface and the systick.
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Then the SystemClock_Config() function is used to configure the system
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clock (SYSCLK) to run at 180 MHz for STM32F4xx Devices.
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The UART peripheral configuration is ensured by the HAL_UART_Init() function.
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This later is calling the HAL_UART_MspInit()function which core is implementing
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the configuration of the needed UART resources according to the used hardware (CLOCK,
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GPIO, DMA and NVIC). You may update this function to change UART configuration.
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The UART/Hyperterminal communication is then initiated.
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The HAL_UART_Receive_DMA() and the HAL_UART_Transmit_DMA() functions allow respectively
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the reception of Data from Hyperterminal and the transmission of a predefined data
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buffer.
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The Asynchronous communication aspect of the UART is clearly highlighted as the
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data buffers transmission/reception to/from Hyperterminal are done simultaneously.
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For this example the TxBuffer is predefined and the RxBuffer size is limited to
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10 data by the mean of the RXBUFFERSIZE define in the main.c file.
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In a first step the received data will be stored in the RxBuffer buffer and the
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TxBuffer buffer content will be displayed in the Hyperterminal interface.
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In a second step the received data in the RxBuffer buffer will be sent back to
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Hyperterminal and displayed.
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The end of this two steps are monitored through the HAL_UART_GetState() function
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result.
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STM32 boards LEDs can be used to monitor the transfer status:
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- LED1 turns ON when the transmission process is complete.
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- LED3 turns ON if transmission/reception is complete and OK.
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- LED3 turns OFF when there is an error in transmission/reception process (HAL_UART_ErrorCallback is called).
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- LED3 toggles when there another error is detected.
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The UART is configured as follows:
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- BaudRate = 9600 baud
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- Word Length = 8 Bits (7 data bit + 1 parity bit)
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- One Stop Bit
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- Odd parity
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- Hardware flow control disabled (RTS and CTS signals)
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- Reception and transmission are enabled in the time
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@note USARTx/UARTx instance used and associated resources can be updated in "main.h"
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file depending hardware configuration used.
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@note When the parity is enabled, the computed parity is inserted at the MSB
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position of the transmitted data.
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@note When the UART parity is enabled (PCE = 1) the data received contain the parity bit.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
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than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@par Keywords
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Connectivity, UART, Printf, Baud rate, RS-232, HyperTerminal, full-duplex, HyperTerminal, DMA,
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Transmission, Reception, Asynchronous
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@par Directory contents
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- UART/UART_HyperTerminal_DMA/Inc/stm32f4xx_hal_conf.h HAL configuration file
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- UART/UART_HyperTerminal_DMA/Inc/stm32f4xx_it.h DMA interrupt handlers header file
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- UART/UART_HyperTerminal_DMA/Inc/main.h Header for main.c module
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- UART/UART_HyperTerminal_DMA/Src/stm32f4xx_it.c DMA interrupt handlers
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- UART/UART_HyperTerminal_DMA/Src/main.c Main program
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- UART/UART_HyperTerminal_DMA/Src/stm32f4xx_hal_msp.c HAL MSP module
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- UART/UART_HyperTerminal_DMA/Src/system_stm32f4xx.c STM32F4xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F446xx devices.
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- This example has been tested with STM32446E-EVAL board and can be
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easily tailored to any other supported device and development board.
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- STM32446E-EVAL Set-up
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- Connect a null-modem female/female RS232 cable between the DB9 connector
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CN25 (USART1) and PC serial port if you want to display data on the HyperTerminal.
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@note
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- Make sure that jumper JP4 pin1 (PA10) and pin2 (uart1_rx) are connected.
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- Make sure that jumper JP6 pin2 (uart1_tx) and pin3 (rs232) are connected.
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- Make sure that jumper JP7 pin1 (uart1_tx) and pin2 (PA9) are connected.
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- Make sure that jumper JP8 pin1 (PA10) and pin2 (rs232) are connected.
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- Hyperterminal configuration:
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- Word Length = 7 Bits
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- One Stop Bit
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- Odd parity
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- BaudRate = 9600 baud
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- flow control: None
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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*/
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