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/**
@page I2C_TwoBoards_MasterTx_SlaveRx_Init I2C example (Polling Mode)
@verbatim
******************************************************************************
* @file Examples_LL/I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/readme.txt
* @author MCD Application Team
* @brief Description of the I2C_TwoBoards_MasterTx_SlaveRx_Init I2C example (Polling Mode).
******************************************************************************
*
* Copyright (c) 2019 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
How to transmit data bytes from an I2C master device using polling mode
to an I2C slave device using interrupt mode. The peripheral is initialized
with LL unitary service functions to optimize for performance and size.
This example guides you through the different configuration steps by mean of LL API
to configure GPIO and I2C peripherals using two P-NUCLEO-WB55.
Boards: P-NUCLEO-WB55 (embeds a STM32WB55RG device)
SCL Pin: PB.8 (CN10, pin 3)
SDA Pin: PB.9 (CN10, pin 5)
______BOARD SLAVE_____ _____BOARD MASTER_____
| ______________| |______________ |
| |I2C1 | | I2C1| |
| | | | | |
| | SCL |_____________________| SCL | |
| | | | | |
| | | | | |
| | SDA |_____________________| SDA | |
| |______________| |______________| |
| __ | | __ |
| |__| | | |__| |
| USER GND|_____________________|GND USER |
|___P-NUCLEO-WB55.Nucleo___| |___P-NUCLEO-WB55.Nucleo___|
The project is splitted in two parts the Master Board and the Slave Board
- Master Board
I2C1 Peripheral is configured in Master mode (Clock 400Khz).
And GPIO associated to User push-button (SW1) is linked with EXTI.
- Slave Board
I2C1 Peripheral is configured in Slave mode (Clock 400Khz, Own address 7-bit enabled).
The user can choose between Master and Slave through "#define SLAVE_BOARD"
in the "main.h" file:
- Comment "#define SLAVE_BOARD" to select Master board.
- Uncomment "#define SLAVE_BOARD" to select Slave board.
The user can disable internal pull-up by opening ioc file.
For that, user can follow the procedure :
1- Double click on the I2C_TwoBoards_MasterTx_SlaveRx_Init.ioc file
2- When CUBEMX tool is opened, select System Core category
3- Then in the configuration of GPIO/I2C1, change Pull-up to No pull-up and no pull-down for the both pins
4- Last step, generate new code thanks to button "GENERATE CODE"
The example is updated with no pull on each pin used for I2C communication
A first program launch, BOARD SLAVE waiting Address Match code through Handle_I2C_Slave() routine.
LED2 blinks quickly on BOARD MASTER to wait for User push-button (SW1) press.
Example execution:
Press the User push-button (SW1) on BOARD MASTER to initiate a write request by Master through Handle_I2C_Master() routine.
This action will generate an I2C start condition with the Slave address and a write bit condition.
When address Slave match code is received on I2C1 of BOARD SLAVE, an ADDR event occurs.
Handle_I2C_Slave() routine is then checking Address Match Code and direction Write.
This will allow Slave to enter in receiver mode and then acknowledge Master to send the bytes.
When acknowledge is received on I2C1 (Master), a TXIS event occurs.
This will allow Master to transmit a byte to the Slave.
Each time a byte is received on I2C1 (Slave), an RXNE event occurs until a STOP condition.
And so each time the Slave acknowledge the byte received a TXIS event occurs on Master side.
Master auto-generate a Stop condition when size of data to transmit is achieved.
The STOP condition generate a STOP event and initiate the end of reception on Slave side.
Handle_I2C_Slave() and Handle_I2C_Master() routine are then clearing the STOP flag in both side.
LED2 is On :
- Slave side if data are well received.
- Master side if transfer sequence is completed.
In case of errors, LED2 is blinking slowly (1s).
@par Keywords
Connectivity, Communication, I2C, Master Rx, Slave Tx, Transmission, Reception, Fast mode, SDA, SCL
@par Directory contents
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Inc/stm32wbxx_it.h Interrupt handlers header file
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Inc/main.h Header for main.c module
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Inc/stm32_assert.h Template file to include assert_failed function
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Src/stm32wbxx_it.c Interrupt handlers
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Src/main.c Main program
- I2C/I2C_TwoBoards_MasterTx_SlaveRx_Init/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55RGVx devices.
- This example has been tested with STM32WB55RGVx board and can be
easily tailored to any other supported device and development board.
- P-NUCLEO-WB55 Set-up
- Connect GPIOs connected to Board Slave I2C1 SCL/SDA (PB.8 and PB.9)
to respectively Board Master SCL and SDA pins of I2C1 (PB.8 and PB.9).
- I2C1_SCL PB.8 (CN10, pin 3) : connected to I2C1_SCL PB.8 (CN10, pin 3)
- I2C1_SDA PB.9 (CN10, pin 5) : connected to I2C1_SDA PB.9 (CN10, pin 5)
- Connect Master board GND to Slave Board GND
- Launch the program.
- Press User push-button (SW1) to initiate a write request by Master
then Slave receive bytes.
@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 (The user can choose between Master
and Slave target through "#define SLAVE_BOARD" in the "main.h" file)
o Comment "#define SLAVE_BOARD" and load the project in Master Board
o Uncomment "#define SLAVE_BOARD" and load the project in Slave Board
- Run the example
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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