how to count the 12 bit ADC count

[sumalatha]

Posted on October 03, 2010 at 11:41

how to count the 12 bit ADC count

[raptorhal2]

Posted on May 17, 2011 at 14:09

Unfortunately ''count'' is not a very helpful term. When the ADC converts an input analog channel, it returns an unsigned integer value. For zero or negative input volts, it returns a value of zero. For 3.3 or higher volts, it returns a value of 4095. (Don't go too negative or too high to avoid damaging the ADC). In between zero and 3.3 volts, the ADC returns a corresponding ratioed value.

No ''counting'' is required, just a simple read. Look at the examples in the Library for further information on how to convert and read a channel. If I have misunderstood your question, please restate. Cheers, Hal

[Andrew Neil]

Posted on May 17, 2011 at 14:09

and sending it to Hyperterminal (or any other application) is a matter of using the USART - again, see examples provided with the library...

[sumalatha]

Posted on May 17, 2011 at 14:09

Thanx for replying ...

actualy in my application my data (Analog temperature value ) i want read this so i am confg here    RCC_Configuration();             SYSTICKS_Configuration();   GPIO_Config();     TIM2_Configuration();     NVIC_Configuration();     USART_Configuration(DBG_USART,115200);    ADC_Config(); for read this channel.... u16 readADC1(u8 channel) {   ADC_RegularChannelConfig(ADC1, channel, 1, ADC_SampleTime_55Cycles5);   // Start the conversion   ADC_SoftwareStartConvCmd(ADC1, ENABLE);   // Wait until conversion completion   while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);   // Get the conversion value   return ADC_GetConversionValue(ADC1); } but i didnt see the count value in hyperterminal so plz tel me what is the thing is wrong thanx

[Andrew Neil]

Posted on May 17, 2011 at 14:09

''i didnt see the count value in hyperterminal''

Nothing in the code you've shown writes anything to the USART! Remember: to the STM32, Hyperterminal is irrelevant! All the STM32 knows is that it transmits bytes through the USART - where those bytes go from there is entirely immaterial to the STM32. See:[DEAD LINK /public/STe2ecommunities/mcu/Lists/ARM%20CortexM3%20STM32/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/ARM CortexM3 STM32/Hyperterminal is not the only terminal program!!&FolderCTID=0x01200200770978C69A1141439FE559EB459D758000626BE2B829C32145B9EB5739142DC17E]https://my.st.com/public/STe2ecommunities/mcu/Lists/ARM%20CortexM3%20STM32/Flat.aspx?RootFolder=%2fpublic%2fSTe2ecommunities%2fmcu%2fLists%2fARM%20CortexM3%20STM32%2fHyperterminal%20is%20not%20the%20only%20terminal%20program%21%21&FolderCTID=0x01200200770978C69A1141439FE559EB459D758000626BE2B829C32145B9EB5739142DC17E

[sumalatha]

Posted on May 17, 2011 at 14:09

thanx andrew  in main ()

while(1)        {       //u16 readADC1(u8 channel);         ADC_val=ADC_GetConversionValue(ADC1);         WriteSerial(DBG_USART,''count '');        Second_Delay(3);         WriteSerial(DBG_USART,ADC_val);         WriteSerial(DBG_USART,''\r\n'');

[Andrew Neil]

Posted on May 17, 2011 at 14:09

How have you verified that your WriteSerial() routine actually works?

eg, have you tried it with a simple ''Hello, world'' program? Remember that serial comms is very, very slow relative the CPU execution - how do you ensure that the USART is ready before you call WriteSerial() again...?

[Andrew Neil]

Posted on May 17, 2011 at 14:09

Sorry - stupid forum playing up again!

[sumalatha]

Posted on May 17, 2011 at 14:09

Dear Andrew….Thanx for reply…

Actually I want to disply the ADC count on USART

and this my code

int main(void)

{

u16 ADC_val;

RCC_Configuration();SYSTICKS_Configuration(); GPIO_Config();Delay_Ms(500);TIM2_Configuration();NVIC_Configuration();USART_Configuration(DBG_USART,115200);Delay_Ms(500);WriteSerial(DBG_USART,'' hello \r\n'');Delay_Ms(500); ADC_Config(); u16 readADC1(u8 channel);while(1){//u16 readADC1(u8 channel);ADC_val=ADC1ConvertedValue;//strcat(ADC_val,'':'');//sprif(ADC_val,ADC_val);WriteSerial(DBG_USART,''SJA '');Second_Delay(3);WriteSerial(DBG_USART,ADC_val);WriteSerial(DBG_USART,''\r\n'');//WriteSerial(DBG_USART,''ADC_val'');}}

And ADC config

void ADC_Config(void)

{ADC_InitTypeDef ADC_InitStructure;ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;ADC_InitStructure.ADC_ScanConvMode = ENABLE;ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;ADC_InitStructure.ADC_NbrOfChannel = 1;ADC_Init(ADC1, &ADC_InitStructure);/* ADC1 regular channel5configuration */ ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 1, ADC_SampleTime_55Cycles5);/* Enable ADC1 DMA *///ADC_DMACmd(ADC1, ENABLE);/* Enable ADC1 */ADC_Cmd(ADC1, ENABLE);/* Enable ADC1 reset calibaration register */ADC_ResetCalibration(ADC1);/* Check the end of ADC1 reset calibration register */while(ADC_GetResetCalibrationStatus(ADC1));/* Start ADC1 calibaration */ADC_StartCalibration(ADC1);/* Check the end of ADC1 calibration */while(ADC_GetCalibrationStatus(ADC1));/* Start ADC1 Software Conversion */ ADC_SoftwareStartConvCmd(ADC1, ENABLE);while (1){}

}

u16 readADC1(u8 channel)

{

ADC_RegularChannelConfig(ADC1, 5, 1, ADC_SampleTime_55Cycles5);// Start the conversionADC_SoftwareStartConvCmd(ADC1, ENABLE);// Wait until conversion completionwhile(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);// Get the conversion value//return ADC_GetConversionValue(ADC1);ADC1ConvertedValue = ADC_GetConversionValue(ADC1);

}

// -------------- The ADC IRQ handler

--------------

/*

void ADC1_2_IRQHandler(void)

{

// Clear ADC1 EOC pending interrupt bitADC_ClearITPendingBit(ADC1, ADC_IT_EOC);// Get converted value of Channelxx converted by ADC1ADC1ConvertedValue = ADC_GetConversionValue(ADC1);cADC1_BUF1[cnt++]=ADC1ConvertedValue;WriteSerial(DBG_USART,cADC1_BUF1);if(cnt==128) {cnt=0;}*/

How have you verified that your WriteSerial() routine actually works?

In hyper

only hello is displayed nt ADC_val

Y it is not displayed? Iam confusing plz help me.:-).

[Andrew Neil]

Posted on May 17, 2011 at 14:09

You still haven't showed the code of your WriteSerial() function!

And you still haven't said how you know that it actually works at all! But this doesn't look right:

Here, you are passing a string to it: 

    WriteSerial( DBG_USART, '' hello \r\n'' );

But here, you are passing a u16 integer value:

WriteSerial( DBG_USART, ADC_val );

That can't be right, surely??!