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STM32M4F415 with Connect EVE

Dave Sclegel
Associate II
Posted on February 27, 2018 at 22:32

Hey there,

iam a stundet and try to create a programm to test some Piezo's on some structures.

I have a STM32 Mini M4 F415 and a Connect Eve Display from mikroe.

I want to get the ADC Value of the peak when i push a plate of Piezos.(4 of them)

The i want to sort them with bubble sort and some calculations.

And after that i want to give the calculated adc value to the Display.

I tried some resolutions i saw on youtube and other Internet pages but i dont got the peaks from my adc to my Array[3] and to the Diplay over SPI.

I use the Cube MX to init my Configuration.

The Calc and sort algorithm and code is not the problem , but this connection between ADC and my array with the peaks. And the the connection to the display.

Does anybody has some links or examples? Where i can lern from?

Actually i have 4 ADC Inputs in Contuious mode .

LG

Dave

PS: Sry for my bad english language. Normally i only tried to prog some easy chips and something big like this

5 REPLIES 5
Andrew Neil
Evangelist III
Posted on February 28, 2018 at 12:42

As always, you need to break the problem down into its distinct parts.

Don't try to solve the whole thing in one go!

Getting the samples from the ADC is a separate problem from displaying stuff on an LCD.

The Calc and sort algorithm and code is not the problem

How do you know that?

Dave Sclegel
Associate II
Posted on February 28, 2018 at 14:29

OK ,

my first problem is to get the peak value from the piezo sensor when i touch the plate where the piezo is located.

How can i configure the ADC Inputs that they record the peak and not all the time when no high input comes?

And after that : Is it possible to get the Values from the ADC to a array?

I tried this following lines.

 First i configured in CubeMX the ADC in

Scan Vonversion Mode to Enabled

Continuous Mode to Enabled

Number of Conversations 4

And Sampling times to 15 Cycles.(12 bits Resolution)

Added some arrays

uint32_t  

adc_buf

[

4

]

,

adc_sensor

[

4

],adc_display[4]

;

void

HAL_ADC_ConvCpltCallback

(

ADC_HandleTypeDef*

hadc

)

{

for

(

int

i

=

0

;

i

<

4

;

i

++

)

{

  

adc_sensor

[

i

]

=

adc_buf

[

i

]

;

  

// From Buf to ADC_Sensor

}

}

After that

main

(

)

{

  ...

       MX_GPIO_Init();

       MX_DMA_Init();

       MX_ADC1_Init();

       MX_SPI1_Init();

   

     HAL_ADC_Start_DMA

(

&

hadc1

,

(

uint32_t *

)

adc_buf

,

4

)

;

    

while

(

1

)

        

{

            adc

_display

[

0

]

=

adc_sensor

[

0

]

;

            adc

_display

[

1

]

=

adc_sensor

[

1

]

;

            adc_display

[

2

]

=

adc_sensor

[

2

]

;

            adc_display

[

3

]

=

adc_sensor

[

3

]

;

           

HAL_Delay

(

1000

)

;

        

}

}

Should be this not a correct code to get the values from the ADC Sensors on Channel 0-3 ?

Posted on February 28, 2018 at 15:11

Dave Sclegel wrote:

How can i configure the ADC Inputs that they record the peak and not all the time

You start by studying the Reference Manual for the chip - look at the ADC section for a description of the available operating modes, and see which most closely matches your requirement.

I've never had cause to look for it, but I don't recall seeing a 'peak-detect' mode. But you need to check for yourself.

If there is no suitable mode, you have 2 choices:

  • Sample continuously, and do the peak-detect in software;
  • Add external peak-detect hardware.
Dave Sclegel
Associate II
Posted on March 01, 2018 at 11:15

Ok, does this chip or STm32 have something like sample and hold?

I know a Arduino has on its analog inputs something like this.

LG

Posted on March 01, 2018 at 11:19

See

https://community.st.com/0D50X00009XkWdWSAV

- have you actually looked in the

documentation to find out?

Dave Sclegel wrote:

I know a Arduino has on its analog inputs something like this.

Arduino is open-source - so take a look to see how they do it ...