STM32F0xx Standard Peripherals Firmware Library
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******************** (C) COPYRIGHT 2014 STMicroelectronics ******************* * @file USART/USART_TwoBoards/DataExchangeInterrupt/readme.txt * @author MCD Application Team * @version V1.4.0 * @date 24-July-2014 * @brief Description of the USART Communication Boards Interrupt Data Exchange * using Interrupt example. ****************************************************************************** * * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License"); * You may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.st.com/software_license_agreement_liberty_v2 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * ******************************************************************************
- Example Description
This example provides a small application in which joystick buttons are used to trigger USART communication using interrupts and though using USART firmware library.
- Hardware Description
To use this example, you need to load it on two STM32F0xx boards (let's call them Board A and Board B) then connect these two boards through UART lines and GND.
*------------------------------------------------------------------------------* | BOARD A BOARD B | | ____________________ ____________________ | | | | | | | | | | | | | | | __________ | | __________ | | | | | USART |____|TX_____________RX|____| USART | | | | | | Device1 |____|RX_____________TX|____| Device2 | | | | | |__________| | | |__________| | | | | | | | | | | O LD1 | | O LD1 | | | | O LD2 Joystick | | O LD2 Joystick | | | | O LD3 _ | | O LD3 _ | | | | O LD4 |_| | | O LD4 |_| | | | | | | | | | | GND O--|-----------------|--O GND | | | |____________________| |____________________| | | | | | *------------------------------------------------------------------------------*
- Note:
- The connection between the pins should use a common Ground.
- Software Description
On Board A, at each joystick buttons press:
- The USART Board A sends the specific command to the USART Board B (the command contains the transaction code (CMD_RIGHT, CMD_LEFT, CMD_UP, CMD_DOWN or CMD_SEL) followed by the number of data to be transmitted (CMD_RIGHT_SIZE, CMD_LEFT_SIZE, CMD_UP_SIZE, CMD_DOWN_SIZE or CMD_SEL_SIZE)
- The USART Board B receives the command and sends the CMD_ACK command to the USART board A
- The USART Board A receives the CMD_ACK command and sends the number of bytes from TxBuffer to the USART Board B.
- The USART Board B compares the number of bytes received with the defined ones into his TxBuffer.
Received data correctness is signaled by LED lightening and though as follow:
- Joystick RIGHT and data correctly received ==> LD2, LD3 ON and LD4 OFF
- Joystick LEFT and data correctly received ==> LD4 ON, LD2 and LD3 are OFF
- Joystick UP and data correctly received ==> LD2 ON, LD3 and LD4 are OFF
- Joystick DOWN and data correctly received ==> LD3 ON, LD2 and LD4 are OFF
- Joystick SEL and data correctly received ==> LD2, LD3 and LD4 are ON
The steps described above can be also initiated and ensured by Board B.
In both boards(Board A or Board B), the data transfers is managed using USARTx_IRQHandler in stm32f0xx_it.c file when USARTx is used.
The SysTick is configured to generate interrupt each 10ms. A dedicated counter inside the SysTick ISR is used to toggle the LD1 each 100ms indicating that the firmware is running. A defined communication timeout is insuring that the application will not remain stuck if the USART communication is corrupted. You can adjust this timeout through the USER_TIMEOUT define inside main.h file depending on CPU frequency and application conditions (interrupts routines, number of data to transfer, baudrate, CPU frequency...).
These operations can be repeated infinitely.
- Directory contents
- USART/USART_TwoBoards/DataExchangeInterrupt/stm32f0xx_conf.h Library Configuration file
- USART/USART_TwoBoards/DataExchangeInterrupt/stm32f0xx_it.c Interrupt handlers
- USART/USART_TwoBoards/DataExchangeInterrupt/stm32f0xx_it.h Interrupt handlers header file
- USART/USART_TwoBoards/DataExchangeInterrupt/main.c Main program
- USART/USART_TwoBoards/DataExchangeInterrupt/main.h Main program header file
- USART/USART_TwoBoards/DataExchangeInterrupt/system_stm32f0xx.c STM32F0xx system source file
- Note:
- The "system_stm32f0xx.c" is generated by an automatic clock configuration tool and can be easily customized to meet user application requirements. To select different clock setup, use the "STM32F0xx_Clock_Configuration_VX.Y.Z.xls" provided with the AN4055 package available on ST Microcontrollers
- Hardware and Software environment
- This example runs on STM32F0xx devices.
- This example has been tested with STMicroelectronics STM320518-EVAL and STM32072B-EVAL including respectively STM32F051R8T6 and STM32F072VBT6 devices and can be easily tailored to any other supported device and development board
- STM320518-EVAL Set-up
- Connect USART1 TX pin (PA.09) to USARTx RX pin
- Connect USART1 RX pin (PA.10) to USARTx TX pin
- Connect GND pins of two boards
- JP3 should be in 5-6 position
- STM32072B-EVAL Set-up
- Connect USART2 TX pin (PD.05) to USARTx RX pin
- Connect USART2 RX pin (PD.06) to USARTx TX pin
- Connect GND pins of two boards
- JP17 should be in 5-6 position
- How to use it ?
In order to make the program work, you must do the following :
- Copy all source files from this example folder to the template folder under Project
- Open your preferred toolchain
- If the used device is STM32F051R8T6 choose STM32F051 project
- Add the following files to the project source list
- Utilities\STM32_EVAL\STM320518_EVAL\stm320518_eval.c
- Add the following files to the project source list
- If the used device is STM32F072VBT6 choose STM32F072 project
- Add the following files to the project source list
- Utilities\STM32_EVAL\STM32072B_EVAL\stm32072b_eval.c
- Add the following files to the project source list
- Rebuild all files and load your image into target memory
- Run the example