ADC on Nucleo 401RE

[willow]

Hello everyone, im trying to understand how the configuration and the use of the ADC is usued on a NUCLEO401RE. I've read the datasheet and reference Manuel but still its not clear.

I have configure the pin A0 on CubeIDE to be an ADC input. But now i don't now how to handle the software part and which functions (HAL or not) to use to read this entry and get their value.

Could someone help me code this ? or give me some indications maybe ?

Im thanking you in advance for your kind help.

[SofLit]

Hello,

You can inspire from the example provided in the STM32CubeF4 package under this link:

https://github.com/STMicroelectronics/STM32CubeF4/tree/master/Projects/STM32F401-Discovery/Examples/ADC/ADC_RegularConversion_DMA

It does use DMA to transfer converted values in the RAM.

[willow]

Thank you for your response, however i the files uploaded on this github, i can't find any particular code that would help me, in the main.c file, besides the ADC configuration that are automatically done by CubeMX, I don't see any kind of software exemple that describe this process...

[SofLit]

Sorry I didn't understand what do you mean by: 

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besides the ADC configuration that are automatically done by CubeMX, I don't see any kind of software exemple that describe this process...

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I pointed you out to an example which was not generated by CubeMx. It's a complete example, you can refer to the readme file to understand how it works.

You can generate the code with CubeMx and add your code from the example I provided to you in / User code start */ / User code end */ section.

[AScha.3 · Accepted solution]

Hi,

1. use Cube + HAL (best for beginning to do something...)

2. how to use the peripherals , just look in the HAL lib (in your generated project -> /Drivers/STM32xx_HAL_Driver/

then open , what you look for, here ADC : stm32xx_hal_adc.c .

Here you see all "standard" calls for this, e.g.  HAL_ADC_Start(..) and short description:

/**
  * @brief  Enable ADC, start conversion of regular group.
  * @note   Interruptions enabled in this function: None.
  * @note   Case of multimode enabled (when multimode feature is available):
  *           if ADC is Slave, ADC is enabled but conversion is not started,
  *           if ADC is master, ADC is enabled and multimode conversion is started.
  * @PAram hadc ADC handle
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_ADC_Start(ADC_HandleTypeDef *hadc)
{

and also the variants, to use it with INT or DMA .

And you can search on github, many projects there, to get some "inspiration" .

(But dont expect click and ready examples, like on Arduino...)

[willow]

Thank you @SofLit and @AScha.3, I have finally manage to do it in deed thnaks to the examples and the HAL library which provide good functions to easily to that. However theres no HAL_Functions that allows to only check if the ADC measure done by HAL_ADC_Start(). Theres 2 possibilities with HAL library :

-  HAL_ADC_PoolForConversion(...) : this function is working with a TimeOut which does not allow to execute other tasks while this period is not over.

- HAL_ADC_GetValue(...) : this function only get the result of the HAL_ADC_Start() measure. But theres no way to check if the measuring process is over before getting the value or not, with the HAL_Library. 

Anyway thank you very much for your help, and maybe see you soon on other STM32 forums.

[AScha.3]

Right, HAL_ADC_PollForConversion(...), is waiting , as its name suggests.

But think: if you have the ADC converting at 1 Msps, it will just wait 1 us for one conversion...not sooo long time. 🙂

If you just want look "is it busy or ready now", try :  HAL_ADC_GetState() .

+

If doing a lot of conversions at hi speed, think about using  HAL_ADC_Start_DMA() , then you get just an INT, when the (new) ADC data block is finished.

[willow]

Thanks a lot for your suggestion about HAL_ADC_GetState(), i'll try it asap. 

In deed, 1 us is not a long time at all but this ADC process is part of another one bigger that has to be run every 5ms and there's a lot of other task to run so the idea is to be the most effecient possible 😉 

I'll investigate about the use of DMA for that. Again, thank you very much for your helpfull answers !

[willow]

@AScha.3 if somehow you are still curious about how to read the value only when the measurement is over, the process i finally used is by gettinf rid of the HAL_functions and to use directly the flags of the ADC and to right my code with the process of a state diagram ( iwould enjoy to show it but i can't because of confidentiality policy)

[AScha.3]

Perfect !

Or try the LL lib, that is fast, but maybe not so comfortable as HAL (at not available for everything).

If you want/need something really fast, write/read the registers direct - you know.

And using HAL , just look how its done - or read in rm, what register you need/can use .

So you get something working really in short time with using HAL , but this is a "bloated" complex lib, that might need a microsecond to set a port pin...just leave it as it is, if you only switch on a LED with this.

But if you want something really fast, write to the pin and do it at cpu speed : 4ns on a H563 at 250M -> e.g.

GPIOG->BSRR = GPIO_PIN_4;

This is the way !