hello, I'm having problems with a K70 ADC channel.

[jeffclawson]

I'm having problems when I use the ADC0_SOURCE__AD5B channel in the below structure.

The code works if I use the ADC0_SOURCE_AD3.   I know that the muxsel must be set to B for the AD5B channel.

Is there any known issues with this channel?

[kerryzhou]

Hi Jeff,

     I find a disorder in your header file:

//  3.3V Current Sensor
const ADC_INIT_CHANNEL_STRUCT ADC0_I_SENSE_3_3V_Channel =
{
    ADC0_SOURCE_AD3,                                            // 3.3V Current Sensor,physical ADC
    ADC_CHANNEL_MEASURE_ONCE | ADC_CHANNEL_START_NOW,           
    NUM_SAMPLES_IN_ONE_RUN,                                     // number of samples in one run sequence              
    START_OFFSET,                                               // 
    PERIOD,                                                     // period in us                                       
    SCALE_RANGE,                                                // scale range of result (not used now)               
    CIRCULAR_BUFFER_SIZE,                                       // circular buffer size (sample count)                
    ADC_PDB_TRIGGER,                                            // logical trigger ID that starts this ADC channel    
    NULL,                                                       // no lwevent used                                    
    0                                                           // lwevent bits                                       
};
//  5V Voltage Sensor
const ADC_INIT_CHANNEL_STRUCT ADC0_VOLT_SENSE_5V_Channel =
{
    ADC0_SOURCE_AD1,                                            // 3.3V Voltage Sensor,physical ADC channel 
    ADC_CHANNEL_MEASURE_ONCE | ADC_CHANNEL_START_NOW,           
    NUM_SAMPLES_IN_ONE_RUN,                                     // number of samples in one run sequence 
    PERIOD,                                                     // period in us                                       
    START_OFFSET,                                               // 
    SCALE_RANGE,                                                // scale range of result (not used now)
    CIRCULAR_BUFFER_SIZE,                                       // circular buffer size (sample count) 
    ADC_PDB_TRIGGER,                                            // logical trigger ID that starts this ADC channel 
    NULL,                                                       // no lwevent used 
    0                                                           // lwevent bits 
};
//  AC Current Sensor
const ADC_INIT_CHANNEL_STRUCT ADC0_I_SENSE_AC_Channel =
{
#if 0
    ADC0_SOURCE_AD5B,      //  not working                    // AC current Sensor,physical ADC channel
#else  
    ADC0_SOURCE_AD3,  // !!!!! using working channel here even thou it is not the correct channel.!!!!!
#endif    
    ADC_CHANNEL_MEASURE_ONCE | ADC_CHANNEL_START_NOW,
    NUM_SAMPLES_IN_ONE_RUN,                                     // number of samples in one run sequence             
    START_OFFSET,                                               // 
    PERIOD,                                                     // period in us                                      
    SCALE_RANGE,                                                // scale range of result (not used now)              
    CIRCULAR_BUFFER_SIZE,                                       // circular buffer size (sample count)               
    ADC_PDB_TRIGGER,                                            // logical trigger ID that starts this ADC channel   
    NULL,                                                       // no lwevent used                                   
    0                                                           // lwevent bits                                      
};

Why ADC0_VOLT_SENSE_5V_Channel, the defination of PERIOD, START_OFFSET is not like other channel?

Whether it should be :

//  5V Voltage Sensor

const ADC_INIT_CHANNEL_STRUCT ADC0_VOLT_SENSE_5V_Channel =

{

    ADC0_SOURCE_AD1,                                            // 3.3V Voltage Sensor,physical ADC channel

    ADC_CHANNEL_MEASURE_ONCE | ADC_CHANNEL_START_NOW,          

    NUM_SAMPLES_IN_ONE_RUN,                                     // number of samples in one run sequ     

   START_OFFSET,                                               //

    PERIOD,                                                     // period in us       

    SCALE_RANGE,                                                // scale range of result (not used now)

    CIRCULAR_BUFFER_SIZE,                                       // circular buffer size (sample count)

    ADC_PDB_TRIGGER,                                            // logical trigger ID that starts this ADC channel

    NULL,                                                       // no lwevent used

    0                                                           // lwevent bits

};

I am not familiar with your mqx code, I just find the definiation has the difference, I don't know whether it has problem when you call : VOLT_SENSE_5V_INDEX

Besides, please also check the PORTx_PCRn[MUX], when the problem happens.

Have a great day,
Jingjing

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[jeffclawson]

The above shows a break point set when the channel fails the fopen.   ADC_Channel_PTR = _vector_table(0x0):

Here is the same break point but this is for the working case.      ADC_Channel_PTR = 0x72183C30

The only difference between the two cases is that the failed case does not execute the below code:

if (channelIndex == I_SENSE_AC_INDEX)

        {

            fclose(m_ADC0);

            InitADCModule_ADC0();

        }

[jeffclawson]

I got the code to work but I shouldn't have had to add the code that I did.

I added the following code to the end of the void CADCModule::ADC_ReadChannel(BYTE channelIndex) function.

       if (channelIndex == I_SENSE_AC_INDEX)

        {

            fclose(m_ADC0);

            InitADCModule_ADC0();

        }

Without this code the next measured channel on the ADC0 channel would fail to open.

Why does the ADC0_SOURCE_AD5B channel measurement cause the next channel to fail to open.

case VOLT_SENSE_5V_INDEX:

        ADC_Channel_PTR = fopen(ADC0 "5V Voltage Sensor", (const char *)&ADC0_VOLT_SENSE_5V_Channel);

        channel = 0;

        break;

All the other channels work as they should.

[kerryzhou]

Hi Jeff,

    Could you tell me what the fopen function retrun when you call ADC_ReadChannel, channelIndex= I_SENSE_AC_INDEX in your code?

   What the ADC_Channel_PTR data value?

void CADCModule::ADC_ReadChannel(BYTE channelIndex)
{ 
    MQX_FILE_PTR ADC_Channel_PTR;  //
    numBytesRead = 0;
    BYTE channel;
    switch (channelIndex)
    {
    case I_SENSE_3_3V_INDEX:
        ADC_Channel_PTR = fopen(ADC0 "3V Current Sensor", (const char *)&ADC0_I_SENSE_3_3V_Channel);
        channel = 0;
        break;
    case I_SENSE_5V_INDEX:
        ADC_Channel_PTR = fopen(ADC1 "5V Current Sensor", (const char *)&ADC1_I_SENSE_5V_Channel);
        channel = 1;
        break;
    case I_SENSE_AC_INDEX:
        ADC_Channel_PTR = fopen(ADC0 "AC Current Sensor", (const char *)&ADC0_I_SENSE_AC_Channel);
        channel = 0;
        break;
    case VOLT_SENSE_5V_INDEX:
        ADC_Channel_PTR = fopen(ADC0 "5V Voltage Sensor", (const char *)&ADC0_VOLT_SENSE_5V_Channel);
        channel = 0;
        break;
    case VOLT_SENSE_3_3V_INDEX:
        ADC_Channel_PTR = fopen(ADC1 "3V Voltage Sensor", (const char *)&ADC1_VOLT_SENSE_3_3V_Channel);
        channel = 1;
        break;
    case TEMP_SENSE_INDEX:
        ADC_Channel_PTR = fopen(ADC1 "Temp Sensor", (const char *)&ADC1_TEMP_SENSE_Channel);
        channel = 1;
        break;
    default:
        ADC_Channel_PTR = NULL;
        channel = 0;
        break;
    }
    if (ADC_Channel_PTR == NULL)
    {
        printf("Cannot open ADC Channel\n");
        fclose(ADC_Channel_PTR);
        if (channel == 0)
        {
            fclose(m_ADC0);
            InitADCModule_ADC0();
        }
        else if (channel == 1)
        {
            fclose(m_ADC1);
            InitADCModule_ADC1();
        }
    }

Please do the debug step by step in your code when you are calling ADC_ReadChannel, whether other ADC channel will make ADC_Channel_PTR == NULL? I find your code when  ADC_Channel_PTR == NULL, then will do ADC channel fclose and init.

Have a great day,
Jingjing

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[jeffclawson]

Alice,

Thanks for your response, I was out of the office on Thursday and Friday.

I've attached the two files used for ADC code.

[Alice_Yang]

Hello Jeff,

- When you use the AD5B channel, please show us the ADC channel initialize code ,

the pin initialize code .

- Also please check whether it is right about  the related registers .

- Then please be sure which pin do you used ?

Hope it helps

Alice