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16. DMA：SPI

DMA：SPI

DMA：SPI1、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: SPI (SPI2) communication via DMA

1、software-hardware

STM32F103CubeIDE
STM32 robot expansion board
USART, SPI, DMA: chip internal peripherals
Key, external Flash (W25Q64) : onboard
Type-C cable or ST-Link
Download or simulate the program of the development board

2、Brief principle

2.1、Hardware schematic diagram

2.2、Physical connection diagram

2.3、Principle of control

SPI

Using SPI2 to communicate with external Flash (W25Q64), SPI related knowledge will not be introduced, you can see the previous [Chapter 3:3.14 Off-chip Flash] tutorial

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 per channel

DMA2 requests per channel

DMA1 channels 4 and 5 are 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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GPIO

SPI

USART

Advanced Settings

Generating code

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

[Chapter 3: Off-chip Flash] Functions introduced are no longer covered

function：SPI_Read_Write_Byte

Function prototypes	uint8_t SPI_Read_Write_Byte(uint8_t BYTE)
Functional Description	1 byte of data is sent via SPI
Input parameters	BYTE：data
Return value	0
Tips	defined DMA_SPI_USE macros used to switch the DMA data transmission or

function：SPI_Write_DMA

Function prototypes	uint16_t SPI_Write_DMA(uint8_t *pTxData, uint16_t Size)
Functional Description	Data is sent via DMA
Input parameters1	pTxData：Data head address
Input parameters2	Size：Number of bytes of data
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT（0-3）

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_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_SPI_TransmitReceive_DMA

Function prototypes	HAL_StatusTypeDef HAL_SPI_TransmitReceive_DMA (SPI_HandleTypeDef hspi, uint8_t pTxData, uint8_t *pRxData,uint16_t Size)
Functional Description	Sending and receiving SPI data via DMA mode
Input parameters1	hspi：SPI handle address
Input parameters2	pTxData：The first address to send data to
Input parameters3	pRxData：The first address to receive data
Input parameters4	Size：The number of bytes of data sent and received
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT

function：HAL_SPI_Transmit_DMA

Function prototypes	HAL_StatusTypeDef HAL_SPI_Transmit_DMA (SPI_HandleTypeDef hspi, uint8_t pData, uint16_t Size)
Functional Description	SPI send function that transfers data using DMA
Input parameters1	hspi：SPI handle address
Input parameters2	pData：The first address of the data
Input parameters3	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 open the serial debugging assistant to observe the phenomenon


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

phenomenon：

Press RESET button: the serial debugging assistant will print the detection status of the external Flash chip;

Press KEY1: The serial debugging assistant will add 1 to the count value and write the value to the external Flash chip;

Press KEY2: The serial debugging assistant will output the numerical value stored in the specified sector of the external Flash chip;

Press KEY3: The serial debugging assistant will erase the specified sector data.

DMA：USART

DMA：I2C