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17. DMA：I2C

DMA：I2C

DMA：I2C1、software-hardware2、Brief principle2.1、Hardware schematic diagram2.2、Physical connection diagram2.3、Principle of control3、Engineering configuration3.1、Notes3.2、Pin configuration4、Main function4.1、User function4.2、HAL library function parsing5、Experimental phenomenon

This tutorial demonstrates I2C (I2C1) communication via DMA

1、software-hardware

STM32F103CubeIDE
STM32 robot expansion board
I2C: chip internal peripheral
OLED: External
Type-C cable or ST-Link
Download or simulate the program of the development board

2、Brief principle

2.1、Hardware schematic diagram

The schematic shows only the I2C (I2C1) interface used in the tutorial

2.2、Physical connection diagram

OLED	STM32 board
VCC	VCC
SCL	SCL
SDA	SDA
GND	GND

2.3、Principle of control

I2C

The use of I2C1 peripheral interface and 0.91 inch OLED display for communication, I2C related knowledge will not be introduced, you can see before [Chapter 3:3.12 I2C communication]

DMA（Direct Memory Access）

STM32F103ZET6 has a total of two DMA controllers, DMA1 has 7 channels, DMA2 has 5 channels;

It is used for high-speed data transfer between peripheral equipment and memory and between memory and memory.

DMA features

The initialization and start of DMA are completed by the CPU, and the transfer process is executed by the DMA controller without the participation of the CPU, so that the CPU resources are saved to do other operations.

DMA1 requests for each channel

DMA2 requests for each channel

DMA1 channel 6 is used in this tutorial

3、Engineering configuration

Project Configuration: Prompts for configuration options in the STM32CubeIDE project configuration process

3.1、Notes

Omitted project configuration: New project, chip selection, project configuration, SYS for pin configuration, RCC configuration, clock configuration, and project configuration content

The project configuration part, which is not omitted, is the key point to configure in this tutorial.


Please refer to [2. Development environment construction and use: STM32CubeIDE installation and use] to understand how to configure the omitted parts of the project.

3.2、Pin configuration

Configure the specified pin function

You can directly select the corresponding pin number in the pin view, and the corresponding option will appear when the mouse is left clicked

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I2C

Advanced Settings

生成代码

4、Main function

This section mainly introduces the functional code written by users. Detailed code can be opened by yourself in the project file we provide, and enter the Bsp folder to view the source code. .

4.1、User function

Functions that have been covered in this tutorial will not be covered anymore.Feel free to refer to the previous tutorials

function：OLED_Draw_Line

Function prototypes	void OLED_Draw_Line(char *data, uint8_t line, bool clear, bool refresh)
Functional Description	Write a single character
Input parameters1	data：Displaying data
Input parameters2	line：Number of rows
Input parameters3	clear：Clear content or ot
Input parameters4	refresh：refreash or not
Return value	None

4.2、HAL library function parsing

The HAL library functions that were covered in the previous tutorial will not be covered


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If you want to find the HAL library and LL library function analysis involved in the entire tutorial, you can view the documents in the folder [8. STM32 Manual: STM32F1_HAL Library and LL Library_User Manual]

function：HAL_I2C_Init

Function prototypes	HAL_StatusTypeDef HAL_I2C_Init(I2C_HandleTypeDef *hi2c)
Functional Description	Initialize the I2C peripheral parameters
Input parameters	hi2c：I2C handle address
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT

function：HAL_I2C_MspInit

Function prototypes	void HAL_I2C_MspInit(I2C_HandleTypeDef* i2cHandle)
Functional Description	Initialize the clock, GPIO and NVIC of the I2C peripheral
Input parameters	i2cHandle：I2C handle address
Return value	None

function：HAL_I2C_MspDeInit

Function prototypes	void HAL_I2C_MspDeInit(I2C_HandleTypeDef* i2cHandle)
Functional Description	Uninitialize the clock, GPIO, and NVIC of the I2C peripheral
Input parameters	i2cHandle：I2C handle address
Return value	None

function：HAL_I2C_Mem_Write

Function prototypes	HAL_StatusTypeDef HAL_I2C_Mem_Write(I2C_HandleTypeDef hi2c, uint16_t DevAddress, uint16_t MemAddress, uint16_t MemAddSize, uint8_t pData, uint16_t Size, uint32_t Timeout)
Functional Description	Write data to a specific memory address of the I2C device
Input parameters1	hi2c：I2C handle address
Input parameters2	DevAddress：Target device address
Input parameters3	MemAddress：Device memory address
Input parameters4	MemAddSize：The size of the device memory address
Input parameters5	pData：Data head address
Input parameters6	Size：Number of bytes of data
Input parameters7	Timeout：Timeout time
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT

function：HAL_DMA_Init

Function prototypes	HAL_StatusTypeDef HAL_DMA_Init(DMA_HandleTypeDef *hdma)
Functional Description	Initialize the DMA controller
Input parameters	hdma：DMA handle address
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT

function：HAL_I2C_Mem_Write_DMA

Function prototypes	HAL_StatusTypeDef HAL_I2C_Mem_Write_DMA(I2C_HandleTypeDef hi2c, uint16_t DevAddress, uint16_t MemAddress, uint16_t MemAddSize, uint8_t pData, uint16_t Size)
Functional Description	Data is written to the internal registers of the I2C device by DMA
Input parameters1	hi2c：I2C handle address
Input parameters2	DevAddress：Target device address
Input parameters3	MemAddress：Device memory address
Input parameters4	MemAddSize：The size of the device memory address
Input parameters5	pData：Data head address
Input parameters6	Size：Number of bytes of data
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT

5、Experimental phenomenon

After downloading the program successfully, press the RESET button of the development board to observe the OLED display


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For program download, please refer to [2. Development environment construction and use: program download and simulation]

phenomenon：

OLED：The first line shows OLED init success! , the second line shows yahboom! , the third line shows This is a DMA+I2c!

DMA：SPI

USB communication