Kinetis Software Development KitのトピックRe: ADC calibration

ADC calibration

Kewal — Wed, 30 Sep 2015 19:13:02 GMT

I am trying to read the voltage level of 12V and 3.3V and I am not sure where I am going wrong,... There is a 3V VRefH and VRefL is GND.

ADC16_DRV_StructInitUserConfigDefault(&adcUserConfig);

ADC16_DRV_Init(ADC16_INSTANCE, &adcUserConfig);

adc16_chn_config_t chnConfig;

// Configure the conversion channel

// differential and interrupt mode disable.

chnConfig.chnIdx = (adc16_chn_t)ADC16_VM12;

#if FSL_FEATURE_ADC16_HAS_DIFF_MODE

chnConfig.diffConvEnable = false;

#endif

chnConfig.convCompletedIntEnable = false;

// Software trigger the conversion.

ADC16_DRV_ConfigConvChn(ADC16_INSTANCE, ADC16_CHN_GROUP, &chnConfig);

// Wait for the conversion to be done.

ADC16_DRV_WaitConvDone(ADC16_INSTANCE, ADC16_CHN_GROUP);

adcValue = 0;

// Fetch the conversion value.

adcValue = ADC16_DRV_GetConvValueSigned(ADC16_INSTANCE, ADC16_CHN_GROUP);

double voltage;

voltage = (int)(adcValue * 0.00000000069849);

I am not able to correctly read the adcValue, Is there something which I need to calibrate to get the correct ADC readings.

Re: ADC calibration

Kewal — Wed, 30 Sep 2015 20:27:36 GMT

by the way that was a mistake i pasted

voltage = (int)(adcValue * 0.00000000069849);

Actually, I am trying to convert using

voltage = (double) (adcValue * (3/65535)));

Re: ADC calibration

jeremyzhou — Thu, 08 Oct 2015 07:03:34 GMT

Hi Kewal,

Before answer your question, I was wondering if you can tell me which MCU you select and what kind of result you got.

I'm looking forward to your reply.
Have a great day,
Ping

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