STM32 ADC acquisition via DMA (HAL Library)

One . Preface

ADC Refers to analog-to-digital conversion , That is, converting analog signals into digital signals . The signal essence of the world is analog signal , Such as speed 、 temperature 、 voice , In essence, they are simulated . However, the electronic devices running on microcontrollers and microprocessors cannot directly read or interpret these analog values , Because they are only in 0 and 1 Up operation . So we need to convert these analog values into 0 and 1, So that microcontrollers and microprocessors can understand them . This is what we call the conversion of analog signals into digital signals . And ADC The corresponding is DAC, That is, to convert digital signals into analog signals .

Two . CubeMX To configure

development environment ：Keil 、 CubeMX
Software version ：5.31 、6.2.1
Using chips ：STM32F103C8T6
development language ：C

CubeMX The configuration is very simple ：Analog->ADCx->INx .

Select multi-channel acquisition here , choice ADC1 , Check IN1 、IN2 . The configuration is as follows ：

• Because it is a multi-channel acquisition , To be opened Scan Conversion Mode Scanning mode .
• Multiple reads are required , So it turns on Continuous Conversion Mode Continuous conversion mode .
• Optional Rank, to IN1、IN2 Select the appropriate sampling channel and sampling period .

add to DMA passageway , Change the mode to Circular Circulation patterns , So every time DMA After successful transmission, the next transmission will be started .

3、 ... and . ADC Read

Start the function ：

HAL_ADC_Start_DMA(ADC_HandleTypeDef* hadc, uint32_t* pData, uint32_t Length)

take ADC Used for reading the remote lever ： The essence of the remote lever is a potentiometer , adopt ADC The remote pole can be obtained by collecting the changed voltage X、Y Remote lever value of axis . Follow the above configuration , In the generated Keil Add the following code to the project to get the collected remote rod value .

uint16_t Joystick_ADC[2];

HAL_ADC_Start_DMA(&hadc1,(uint32_t*)&Joystick_ADC,2);

Be careful ： If open ADC Of DMA It is possible that the main function cannot continue to run after receiving because the set sampling period is too short , Trigger frequently DMA Accept the interruption . Can be in CubeMX Zhongba Rank Middle channel Sampling period Samplink Time Make it longer , Close test effectively .