HAL_ADC_PollForConversion vs HAL_ADC_GetValue

[skon.1]

Hello, 

I see ADC examples that use the following functions:

1.HAL_ADC_PollForConversion.

2.HAL_ADC_GetValue.

Questions:

a. What's the difference between both functions ?

b. In my application I simply want to get the ADC voltage when a user sends a command. What function should I use ?

[Elkin Granados]

Hi, HAL_ADC_PollForConversion start the conversion in the selected channel and keep waiting till the conversion is done, after that you must to call HAL_ADC_GetValue to store the conversion value, you need to use both functions in this order. So, in you application just catch the command and call them both functions.

[TDK]

Recommend usage of HAL functions is found in the source file.

You can also inspect the code. HAL_ADC_GetValue merely reads the DR register. You will need to start and wait for the conversion using HAL_ADC_PollForConversion.

                       *** Execution of ADC conversions ***
  ==============================================================================
  [..]  
  (#) ADC driver can be used among three modes: polling, interruption,
      transfer by DMA.    
 
     *** Polling mode IO operation ***
     =================================
     [..]    
       (+) Start the ADC peripheral using HAL_ADC_Start() 
       (+) Wait for end of conversion using HAL_ADC_PollForConversion(), at this stage
           user can specify the value of timeout according to his end application      
       (+) To read the ADC converted values, use the HAL_ADC_GetValue() function.
       (+) Stop the ADC peripheral using HAL_ADC_Stop()

[skon.1]

Thanks,

Where can I get this file ?

[TDK]

> Where can I get this file ?

It should be included in your project directory somewhere.

The latest version is also available here:

https://github.com/STMicroelectronics/STM32CubeF4/blob/master/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_adc.c