ADC12 problem

[aialinux]

Posted on July 24, 2006 at 14:45

ADC12 problem

[aialinux]

Posted on March 19, 2006 at 21:22

I am using STR710 ADC12.The program as below:

ADC12_ChannelSelect(ADC12_CHANNEL0);

/* Start the Converter */

ADC12_ConversionStart();

/* Wait until the availabiliy of data in the specific flags */

while (ADC12_FlagStatus (ADC12_DA0)==RESET);

/* Get the conversion result from the correponding Data register */

ADC_Reg = ADC12_ConversionValue(ADC12_CHANNEL0);

But the program can't run out of : while (ADC12_FlagStatus (ADC12_DA0)==RESET);

[aialinux]

Posted on March 22, 2006 at 21:24

Yes! The problem is still the same.

It can't run out of : while (ADC12_FlagStatus (ADC12_DA0)==RESET);

[ezanen9]

Posted on March 27, 2006 at 05:54

Hi,

Just a suggestion: did you set the ADC_en bit in the PCU_BOOTCR register?

If not the ADC will not run and the sample ready flag not set.

Regards,

Jimmey

[gawied]

Posted on July 19, 2006 at 09:05

Hi Dom

Did you solve the ADC12 problem? If so please let me know what was wrong, as I am getting the same problem - not every time though, which makes it even more scary ;-).

Cheers

Gawie

[gawied]

Posted on July 21, 2006 at 05:46

Hi

I solve my problem, but I am not quite sure of my solution. Maybe somebody can shed some light on the issue.

On startup I did initialise the ADC by calling the following functions:

// Configure the used analog input to HI_AIN

GPIO_Config (GPIO1, 0x0001, GPIO_HI_AIN_TRI);

// Initialize the conveter register.

ADC12_Init();

// Configure the ADC prescaler to have a sampling frequency = 500Hz

ADC12_PrescalerConfig(500);

// Select the conversion mode=single channel

ADC12_ModeConfig (ADC12_SINGLE);

And when ever I want to get an ADC value I did a few (100 or so) conversions and then calculated the average. I called the functions as follow:

// Select the channel to be converted

ADC12_ChannelSelect(ADC12_CHANNEL0);

// Start the Converter

ADC12_ConversionStart();

// Wait until the availabiliy of data in the specific flags

while (!ADC12_FlagStatus (ADC12_DA0));

// Get the conversion result from the corresponding Data register

ADC_Reg = ADC12_ConversionValue(ADC12_CHANNEL0);

My problem was that the flag, indicating that the conversion was completed, was not set on some occasions.

I fixed it by doing the init routines not just at startup, but also every time I wanted to do an ADC conversion. Does this make sense and do I have to init the ADC before every conversion?

Any comment would help ;-).

Thanks,

Gawie

[hichem2]

Posted on July 21, 2006 at 13:01

Hello,

Normally you don't need to initialize the ADC before every conversion, please could you tell me wich library version you are using and check the

ADC12_Init(); funtion body .

cheers,

Hich

[gawied]

Posted on July 21, 2006 at 18:11

Hi

I am using libary ver 3.1 and the ADC12_Init() looks like follows:

void ADC12_Init(void)

{

/* Initiate ADC12 registers to their reset values */

ADC12->CSR = 0x0000;

ADC12->CPR = 0x0005;

}

Cheers

Gawie

[gawied]

Posted on July 24, 2006 at 14:45

Ok, I solved my problem!

I had more than one channel selected in ADC12->CSR while I was using the ADC in single conversion mode and that was the cause why the completion flag was never set.

Cheers

Gawie