K22F analog reads

shibbs — Sat, 19 Mar 2016 21:05:29 GMT

Hello, I am having trouble performing analog reads with the K22F board. I am running adc_lptmr_trigger_frdmk22f example project, and modifying the pin selection within there, using KSDK 1.2, in kinetis design studio 3 on a Mac.

The results are good for ADC0_SE23 and ADC0_SE8
I have not been able to get it working for ADC0_SE21, ADC0_SE7b, ADC0_SE22. Have been selecting the pins via the ADC_INPUT_CHAN variable. The ADCH bits are being set properly, and I have scoped the pin to see that the desired signal is indeed reaching it. However I get output that is essentially pin noise.
Using single ended reads (differential reads give all low)
I can confirm that the pins are set to default/analog in the mux registers
I have tried with ADC_INST as 0 and 1

I have spent a few hours on this trying different variations of registers and reading around on this forum, but so far I have had no luck getting it working. Is there something I'm missing here?

Re: K22F analog reads

Alice_Yang — Mon, 21 Mar 2016 04:14:54 GMT

Hello stephen,

Please tell me you use which board or the chip's part number .

Also please show the code about configure the ADC .

Alice

Re: K22F analog reads

shibbs — Mon, 21 Mar 2016 15:19:30 GMT

Thanks Alice,

We are using the frdmK22F board, so the K22F512. As for the code, we're just using the adc_lptmr_trigger_frdmk22f example located at /KSDK_1.2.0/examples/frdmk22f/demo_apps/adc_hw_trigger/lptmr/kds/ . Some of the most relevant code is attached below, the only changes that we made were to change the ADC_INPUT_CHAN and to explicitly set up pin PTD4 to default mode.

#define ADC_INPUT_CHAN2    (kAdc16Chn8) /* default input signal channel */
#define  ADC_INST2 0U
static int32_t init_adc(uint32_t instance)
{
#if FSL_FEATURE_ADC16_HAS_CALIBRATION
    adc16_calibration_param_t adcCalibraitionParam;
#endif
    adc16_converter_config_t adcUserConfig;
    adc16_chn_config_t adcChnConfig;
    ADC16_DRV_StructInitUserConfigDefault(&adcUserConfig);
 
    ADC16_DRV_Init(instance, &adcUserConfig);
#if FSL_FEATURE_ADC16_HAS_CALIBRATION
    // Auto calibraion.
    ADC16_DRV_GetAutoCalibrationParam(instance, &adcCalibraitionParam);
    ADC16_DRV_SetCalibrationParam(instance, &adcCalibraitionParam);
#endif
    // Initialization ADC for
    // 12bit resolution, interrrupt mode, hw trigger enabled.
    // normal convert speed, VREFH/L as reference,
    // disable continuouse convert mode.
    ADC16_DRV_StructInitUserConfigDefault(&adcUserConfig);
    adcUserConfig.hwTriggerEnable = true;
    adcUserConfig.continuousConvEnable = false;
 
    ADC16_DRV_Init(instance, &adcUserConfig);
    // Install Callback function into ISR
    ADC_TEST_InstallCallback(instance, 0U, adc_chn0_isr_callback);
    ADC_TEST_InstallCallback(instance, 1U, adc_chn1_isr_callback);
    adcChnConfig.chnIdx = (adc16_chn_t)ADC_INPUT_CHAN2;
#if FSL_FEATURE_ADC16_HAS_DIFF_MODE
    adcChnConfig.diffConvEnable = false;
#endif /* FSL_FEATURE_ADC16_HAS_DIFF_MODE */
    adcChnConfig.convCompletedIntEnable = true;
    // Configure channel0
    ADC16_DRV_ConfigConvChn(instance, 0U, &adcChnConfig);
    // Configure channel1, which is used in PDB trigger case
    ADC16_DRV_ConfigConvChn(instance, 1U, &adcChnConfig);
    return 0;
}
int main(void)
{
    uint8_t cnt;
    int32_t row;
    // init the hardware board
    hardware_init();
    PORT_HAL_SetMuxMode(PORTD,4u,1);
    PRINTF("\r\nadc_hw_trigger demo running...\r\n\r\n");
    PORT_HAL_SetMuxMode(PORTD,4u,kPortPinDisabled);
#ifdef USE_DAC_OUT_AS_SOURCE
    // use DAC to generate the sine wave
    dac_gen_wave();
#else
    // If no DAC can be use, then a function generator should
    // be used to generate a signal wave, and connect to ADC input
#endif
    // initialize the ADC
    if (init_adc(ADC_INST2))
    {
        PRINTF("Failed to do the ADC init\n");
        return -1;
    }
    // setup the HW trigger source
    init_trigger_source(ADC_INST2);
    // init the print chart array
    sparse_reset();
    for (cnt = 0; cnt < NR_SAMPLES; cnt++)
    {
        uint16_t result;
        double tmpRatio;
        while (gAdcDone != true)
        {
            ;
        }
        result = ADC16_DRV_GetConvValueRAW(ADC_INST2, (uint32_t)gCurChan);
        gAdcDone = false;
        // insert the sample data into the sparse matrix
        tmpRatio = (double)result / RATIO;
        row = (int32_t)tmpRatio;
        if (row >= CHART_ROWS)
        {
            row = CHART_ROWS - 1;
        }
        // fill one samples into sparse matrix
        sparse_insert(row, cnt);
    }
    // print the chart
    for (row = CHART_ROWS - 1; row >= 0; row --)
    {
        sparse_node_ptr p = gChartHead[row];
        uint32_t last = 0;
        while (p)
        {
            for (; last < p->value; last++)
            {
                PRINTF(" ");
            }
            PRINTF("*");
            p = p->next;
            last++;
        }
        PRINTF("\r\n");
    }
    // disable the adc0
    ADC16_DRV_Deinit(ADC_INST2);
    // disable hw trigger source
    deinit_trigger_source(ADC_INST2);
#ifdef USE_DAC_OUT_AS_SOURCE
    // disable dac source
    dac_stop_wave();
#endif
    while(1)
    {}
}
    }
    // disable the adc0
    ADC16_DRV_Deinit(ADC_INST2);
    // disable hw trigger source
    deinit_trigger_source(ADC_INST2);
#ifdef USE_DAC_OUT_AS_SOURCE
    // disable dac source
    dac_stop_wave();
#endif
    while(1)
    {}
}

Thank you,

Steve

Re: K22F analog reads

shibbs — Mon, 28 Mar 2016 23:17:51 GMT

Any update here?

Re: K22F analog reads

Alice_Yang — Tue, 29 Mar 2016 04:24:38 GMT

Hello Stephen,

In the FRDM-K22 board , the chip is MK222FN512VLH12, it is the 64 LQFP package,

from the Reference Manual -> Pinout, we can see that this chip does not support the

signal of "adc0_se21" "adc0_se22" , it support the signal of "adc0_se7b", please connect the

right pin :

And you said PTD4 pin, do you think which channel is this pin ?

Alice

Re: K22F analog reads

shibbs — Tue, 29 Mar 2016 16:43:27 GMT

Thank you Alice,

I had not realized that the MK22FN512VLH12 and the MK22DN512VLH5 were so different. I was using the family data sheet for the MK22DN512VLH5 (K22P64M50SF4.pdf) which shows that the PTD4 pin can be used for ADC0_SE21.

Thank you,

-Stephen

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