ADC 1 problem with STM8S-Discovery

[u23]

Posted on May 26, 2015 at 13:55

Hi,

I have problem with ADC1 conversions on STM8S-Discovery. I have configured the analogic inputs following: PB4 - AN4 PB5 - AN5 PB6 - AN6 unsigned char ADC_Config_INT ( void ) {          GPIO_Init(ADC_PORT,ADC_15V_PIN, GPIO_MODE_IN_FL_NO_IT);     GPIO_Init(ADC_PORT,ADC_CURR_PIN, GPIO_MODE_IN_FL_NO_IT);     GPIO_Init(ADC_PORT,ADC_5V_PIN, GPIO_MODE_IN_FL_NO_IT);       /* De-Init ADC1 peripheral */   ADC1_DeInit();        /* Enable EOC interrupt */   ADC1_ITConfig(ADC1_IT_EOCIE, ENABLE);        /* Enable conversion data buffering */   ADC1_DataBufferCmd(ENABLE);        /* Enable scan mode conversion */   ADC1_ScanModeCmd(ENABLE);   /* Init ADC1 peripheral */     /* ADC1 Channel 4 */   ADC1_Init(ADC1_CONVERSIONMODE_CONTINUOUS, ADC1_CHANNEL_4, ADC1_PRESSEL_FCPU_D8, \             ADC1_EXTTRIG_TIM, DISABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_CHANNEL4,\             DISABLE);                              /* ADC1 Channel 5 */   ADC1_Init(ADC1_CONVERSIONMODE_CONTINUOUS, ADC1_CHANNEL_5, ADC1_PRESSEL_FCPU_D8, \             ADC1_EXTTRIG_TIM, DISABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_CHANNEL5,\             DISABLE);                              /* ADC1 Channel 6 */   ADC1_Init(ADC1_CONVERSIONMODE_CONTINUOUS, ADC1_CHANNEL_6, ADC1_PRESSEL_FCPU_D8, \             ADC1_EXTTRIG_TIM, DISABLE, ADC1_ALIGN_RIGHT, ADC1_SCHMITTTRIG_CHANNEL6,\             DISABLE);                               /* Enable ADC1 */   ADC1_Cmd(ENABLE);              return 0; } the interrupt function code is: #define ADC_SAMPLES 8 extern volatile uint16_t ValueCh4[ADC_SAMPLES];             extern volatile uint16_t ValueCh5[ADC_SAMPLES];             extern volatile uint16_t ValueCh6[ADC_SAMPLES];             volatile uint8_t Index = 0; extern uint8_t ArrayEmpty; /**   * @brief  ADC1 interrupt routine.   * @param  None   * @retval None   */  INTERRUPT_HANDLER(ADC1_IRQHandler, 22) {             if ( ADC1_GetFlagStatus(ADC1_FLAG_EOC) != RESET )             {                 ValueCh4[Index] = ADC1_GetBufferValue(4);                 ValueCh5[Index] = ADC1_GetBufferValue(5);                 ValueCh6[Index] = ADC1_GetBufferValue(6);                 // Controlla se ho acquisito un numero sufficiente di campioni                 if( Index >= ADC_SAMPLES )                         {                             ArrayEmpty = 1;                             Index = 0;                         }                     else{                             Index++;                         }                                    ADC1_ClearFlag(ADC1_FLAG_EOC);             }                  return; } The ''ADC1_GetBufferValue'' function return the value correct the first time only. If I modified the value on pin PB4 for example, continuos at read the previous value. Any idea? Thanks

[u23]

Posted on May 28, 2015 at 14:07

I attached the project.

The ADC interrupt is occurs, but the ''ADC1_GetBufferValue(ADC1_CHANNEL_4)'' not return the updated value on the channel 4. This function return the read first value. A

ny suggestions?

Thanks ________________ Attachments : Project1.rar : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HzNB&d=%2Fa%2F0X0000000bKg%2FfMUpHYx5zpJf69vgPIFnEFm63eHgHQ_e.eRcebHDUa4&asPdf=false

[u23]

Posted on June 04, 2015 at 12:09 The original post was too long to process during our migration. Please click on the provided URL to read the original post. https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I6l0&d=%2Fa%2F0X0000000buj%2FjUQeQkRoZH8IXlJ4.jBsmRUt0E9vh9WFtPYC34bTGbo&asPdf=false

[laith charles]

Posted on December 07, 2016 at 18:05

I am having a similar issue...  I have to restart the program to refresh this value.

[Bao Son Le]

Posted on January 10, 2017 at 21:14

You should read ADC chapter in reference manual again. Your continuous scan mode is always convert N channels (from channel 0) automatically. Multi channel c

ontinuous scan is not recommend.

You can combine timer trigger with single mode on each channel, refer post of @LaserElettronicaSRL

[Mojzesz Winnetou]

Posted on September 12, 2017 at 10:10

Hi

Problem with conversion in single scan mode is in ADC1->CSR register. After correct conversion it's necessary to reload value of this register by following way:

ADC1->CSR &= (uint8_t)(~ADC1_CSR_CH);
ADC1->CSR |= (uint8_t)(ADC1_CHANNEL_5);
ADC1->CR1 &= (uint8_t)(~ADC1_CR1_CONT);�?�?�?�?�?�?�?

This 3 lines should be placed in ADC1 INTERRUPT_HANDLER after Interrupt flag clear:

 INTERRUPT_HANDLER(ADC1_IRQHandler, 22)
{
 /* Clear interrupt flag */
 ADC1_ClearITPendingBit(ADC1_IT_EOC);
 /* Workaround for ADC ScanMode issue (Reconfig ADC) */
 ADC1->CSR &= (uint8_t)(~ADC1_CSR_CH);
 ADC1->CSR |= (uint8_t)(ADC1_CHANNEL_5);
 ADC1->CR1 &= (uint8_t)(~ADC1_CR1_CONT);
 /* User code */
}�?�?�?�?�?�?�?�?�?�?�?�?�?

Below I show correct ADC configure for single scan mode with external trigger from TIM1 overflow:

/* Init timer 1 */
 TIM1_DeInit(); //deinit first configuration
 TIM1_TimeBaseInit(0, TIM1_COUNTERMODE_UP, TIM1_TOP, 0); //set frequency of timer 1
 TIM1_SelectOutputTrigger(TIM1_TRGOSOURCE_UPDATE); //set TRGO active when UPDATE event
 /* Init ADC */
 ADC1_DeInit(); //deinit first configuration of ADC
 ADC1_Init(ADC1_CONVERSIONMODE_SINGLE, //single conversion mode
 ADC1_CHANNEL_5, //in scan mode, this is the last channel to conversion
 ADC1_PRESSEL_FCPU_D4, //set prescaler to 4 (16MHz / 4 = 4MHz [MAX 6MHz])
 ADC1_EXTTRIG_TIM, //select external trigger from timer 1
 ENABLE, //enable external trigger
 ADC1_ALIGN_RIGHT, //align ADC data to right
 ADC1_SCHMITTTRIG_CHANNEL0, //any Schmit trigger
 DISABLE); //because it's disable
 ADC1_ScanModeCmd(ENABLE); //enable scan mode
 ADC1_DataBufferCmd(ENABLE); //enable buffers for ADC
 ADC1_ITConfig(ADC1_IT_EOCIE, ENABLE); //enable End Of Conversion IT
 ADC1_Cmd(ENABLE); //enable ADC�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?

For start conversion we need to start timer and global interrupts:

/* Enable global interrupt flag */ 
enableInterrupts();
/* Enable main measure timer, for ADC triggering */
TIM1_Cmd(ENABLE);�?�?�?�?�?�?�?�?�?�?

Now ADC should work correct in single scan mode with external trigger.