ADC with DMA with SW Trigger on L486 MCU

[Andy Pevy]

Posted on June 09, 2017 at 12:06

I wish to use ADC1 to measure 6 channels and to have the results DMAd into memory.

I am using CubeMX V4.21 and I think that I have set the parameters up correctly

(See attached screen snip ADC_DMA_1 to 3.PNG)

This sequence is to be triggered by S/W to run once, terminate and then run again sometime later.

(This is in a loop for testing at the moment).

The DMA happens as I am seeing the ADC readings appear in the adc1_data array and I get the DMA half complete interrupt handler being called but not the end of sequence interrupt.

What am I doing wrong please.....

My code is :-

uint16_t adc1_data[6];

#define ADC1_BUFFER_SIZE_IN_BYTES 12

#define   ADC1_TEMP1_OFFSET                   0

#define

ADC1_TEMP2_OFFSET                    1

#define

ADC1_VBOOST_OFFSET                 2

#define

ADC1_VHLC_OFFSET                       3

#define

ADC1_INTERNAL_TEMP_OFFSET  4

#define

ADC1_VREF_OFFSET                       5

volatile bool adc1_active_flag;

void start_adc1(void){    HAL_StatusTypeDef status;

   set_VDDA_PWR_EN(ANALOG_POWER_ON);

   set_nVMON_ENABLE(VMON_ENABLE_ON);    set_nTEMP_SENSOR_PWR_EN(TEMP_SENSOR_POWER_ON);

   adc1_active_flag = TRUE;

   osDelay(2);

   status = HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED);

   if(HAL_OK != status)    {       // Blah    }

   status = HAL_ADC_Start_DMA(&hadc1, (uint32_t *)adc1_data, ADC1_BUFFER_SIZE_IN_BYTES);

   if(HAL_OK != status)    {       // Blah    }}

void HAL_ADC_ConvHalfCpltCallback(ADC_HandleTypeDef* hadc)

{    static bool apapap;    if(ADC1 == hadc->Instance)    {       // Voltage subsystem...       apapap = TRUE; // <<< Gets here....    }    if(ADC2 == hadc->Instance)    {       // Blah   }   

   if(ADC3 == hadc->Instance)

   {       // Blah    }}void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc){    if(ADC1 == hadc->Instance)    {       if(__HAL_ADC_GET_FLAG(hadc, ADC_FLAG_EOS)) // << Never gets here...

:(

      {          // Voltage subsystem...          adc1_active_flag = FALSE;          set_nTEMP_SENSOR_PWR_EN(TEMP_SENSOR_POWER_OFF);          set_nVMON_ENABLE(VMON_ENABLE_OFF);       }       if(__HAL_ADC_GET_FLAG(hadc, ADC_FLAG_EOC))       {          // Voltage subsystem...          adc1_active_flag = FALSE;          set_nTEMP_SENSOR_PWR_EN(TEMP_SENSOR_POWER_OFF);          set_nVMON_ENABLE(VMON_ENABLE_OFF);       }    }    if(ADC2 == hadc->Instance)    {       // Blah    }    if(ADC3 == hadc->Instance)    {       // Blah    }} // freeRTOS task... // /* Infinite loop */ for(;;) {    if(MODE_BLAH == my_mode)    {    osDelay(1000);

   // We have been woken so do something...

   start_adc1();

   // Block until the scan has completed...

   // Better way would be to use a mutex block here... [AP]    while(TRUE == read_adc1_active_flag())    {       ;    }

   len = sprintf(adc1_test, 'T1:%d\tT2%dVB:%d\tVHLC:%d\tMCU_Temp:%d\tVref:%d\n',

   adc1_data[ADC1_TEMP1_OFFSET],    adc1_data[ADC1_TEMP2_OFFSET],    adc1_data[ADC1_VBOOST_OFFSET],    adc1_data[ADC1_VHLC_OFFSET],    adc1_data[ADC1_INTERNAL_TEMP_OFFSET],    adc1_data[ADC1_VREF_OFFSET]);

   // Trace the output...

   str_trace('ADC Vals:%s', adc1_test);

   }

}

[Zt Liu · Accepted solution]

Posted on June 09, 2017 at 12:20

Hi, 

as in your second png, dma packet size is half wold, 16bit, 

You can't use 

ADC1_BUFFER_SIZE_IN_BYTES;

Probably, it's

#define ADC_CHANNEL_CNT   6

status = HAL_ADC_Start_DMA(&hadc1, (uint32_t *)adc1_data, ADC_CHANNEL_CNT)

by the way, if you check you adc buffer, you'll probably see those 6 adc data already lying there.

Good Luck!

[Andy Pevy]

Posted on June 09, 2017 at 12:29

Brilliant, that did the trick..

Thanks for the answer.

But...

I draw your attention to the Doxygen header for the relevant function :-

/**

* @brief Enable ADC, start conversion of regular group and transfer result through DMA. * @note Interruptions enabled in this function: * overrun (if applicable), DMA half transfer, DMA transfer complete. * Each of these interruptions has its dedicated callback function. * @note Case of multimode enabled (when multimode feature is available): HAL_ADC_Start_DMA() * is designed for single-ADC mode only. For multimode, the dedicated * HAL_ADCEx_MultiModeStart_DMA() function must be used. * @param hadc: ADC handle * @param pData: Destination Buffer address. * @param Length: Length of data to be transferred from ADC peripheral to memory (in bytes)  * @retval HAL status. */HAL_StatusTypeDef HAL_ADC_Start_DMA(ADC_HandleTypeDef* hadc, uint32_t* pData, uint32_t Length)

The Length argument does specifically  say 'in BYTES' not 'Number of transfers required'..

Can this be updated sometime soon so others don't fall into the same trap.

Andy

[Zt Liu]

Posted on June 09, 2017 at 12:33

* @param Length: Length of data to be transferred from ADC peripheral to memory (

in bytes

)

This description is definitely incorrect. 

:((

[Imen.D]

Posted on June 14, 2017 at 12:16

Hi

Pevy.Andy

and

Liu.Zhitai

,

I highlighted internally your feedback about the incorrect description.

Regards

Imen

[Evgeny Erlihman]

Posted on November 02, 2017 at 14:48

Hi

DAHMEN.IMEN

,

I am using the NUCLEO-H743ZI with a project generated by Cube 4.0. TheHAL_ADC_Start_DMA documentation states:

@param Length: Length of data to be transferred from ADC peripheral to memory (in bytes)

Is it still a documentation bug or is it intentional this time?

Thanks,

Evgeny