ADC random values in KL02

anther — Thu, 26 May 2016 12:56:10 GMT

Hi, I'm working with a Kl02 and I'm trying to read an ADC channel but always I read random values. I've been working with different codes and ways but the mistake continues and I can't figure out the problem.

The uC is the MKL02Z32VFG4. QFN 16

I'm trying to read values from the port PTB0 -> ADC0 Channel 6 [ PIN 8 ]

To verify the correct configuration of the ADC peripheral I'm reading form other channel in this case I'm usign the port PTB5 -> ADC0 Channel 1 [PIN 13] . This channel works perfectly and I can read right values.

This is my schematic. In the PIN labeled as TRIGGER_3.3 I can read perfectly the ADC value. But the PIN labeled as MA give me always random values.

Code to configure the ADC:

I'm working with Kinetis Desing Studio 3.1.0 and KSDK 1.3.0

int Interface_Adc_Init( t_Interface_Adc_Handle *adc_handle,

t_Interface_Adc_Device adc )

{

adc16_chn_config_t adcCalibrationChnConfig;

if( adcList[adc].installed == Interface_Adc_Free_Device )

{

ADC16_DRV_StructInitUserConfigDefault( &adc_handle->adc_config_info );

adc_handle->adc_config_info.lowPowerEnable = false;

adc_handle->adc_config_info.resolution = kAdc16ResolutionBitOfSingleEndAs12;

adc_handle->adc_config_info.asyncClkEnable = false;

adc_handle->adc_config_info.clkSrc = kAdc16ClkSrcOfBusClk;

adc_handle->adc_config_info.clkDividerMode = kAdc16ClkDividerOf2;

adc_handle->adc_config_info.longSampleTimeEnable = false; //true;

adc_handle->adc_config_info.longSampleCycleMode = kAdc16LongSampleCycleOf16;

if ( kStatus_ADC16_Success != ADC16_DRV_Init( adc_handle->device, &adc_handle->adc_config_info ) )

{

while(1); // only for test use

}

adc_handle->adc_average_cfg.hwAverageEnable = false;//true;

adc_handle->adc_average_cfg.hwAverageCountMode = kAdc16HwAverageCountOf16;

if( kStatus_ADC16_Success != ADC16_DRV_ConfigHwAverage( adc_handle->device, &adc_handle->adc_average_cfg ) )

{

while(1); // only for test use

}

adcCalibrationChnConfig.chnIdx = kAdc16Chn31;

adcCalibrationChnConfig.convCompletedIntEnable = false;

// Configure channel0

ADC16_DRV_ConfigConvChn(adc_handle->device, 0U, &adcCalibrationChnConfig);

// Auto calibration.

ADC16_DRV_GetAutoCalibrationParam( adc_handle->device, &adc_handle->adc_calib_param );

ADC16_DRV_SetCalibrationParam( adc_handle->device, &adc_handle->adc_calib_param );

}

return( 0 );

}

/* END */

Code to start and read a conversion

int Interface_Adc_Start_Measure( t_Interface_Adc_Handle *adc_handle, t_Adc_Channels channel, bool intEnable )

{

adc16_chn_config_t adc_channel_cfg;

adc_channel_cfg.chnIdx = (adc16_chn_t)channel;

adc_channel_cfg.convCompletedIntEnable = intEnable;

ADC16_DRV_ConfigConvChn( adc_handle->device, 0, &adc_channel_cfg );

return( 0 );

}

int Interface_Adc_Stop_Conversion( t_Interface_Adc_Handle *adc_handle )

{

ADC16_DRV_PauseConv( adc_handle->device, 0 );

return(0);

}

int Interface_Adc_Read_Measure( t_Interface_Adc_Handle *adc_handle )

{

ADC16_DRV_WaitConvDone( adc_handle->device, 0 );

return ( ADC16_DRV_GetConvValueRAW( adc_handle->device, 0 ) );

}

Main

static t_Interface_Adc_Handle adc0;

int main(void)

{

static float adc;

static float adc_Convertion;

// Configure board specific pin muxing

hardware_init();

Api_System_Tick_Init( 100, Util_Clock_Base_Update ); //100uS 0.1ms.

Api_System_Tick_Start( );

Util_Periodic_Timer_Init( &systemTick1000, 10000 ); //1000ms

Interface_Adc_Init( &adc0, Interface_Adc0 );

/* Synchronous tasks */

while(1)

{

if( Util_Periodic_Timer_Execute( &systemTick1000 ) ) //1000ms.

{

Interface_Adc_Start_Measure( &adc0, Interface_Adc_Channel6, false );

adc =Interface_Adc_Read_Measure( &adc0 ); <- This channel fail.

Interface_Adc_Stop_Conversion( &adc0 );

Interface_Adc_Start_Measure( &adc0, Interface_Adc_Channel1, false );

adc =Interface_Adc_Read_Measure( &adc0 ); <- This channel works fine.

Interface_Adc_Stop_Conversion( &adc0 );

}

}//while(1)

}

Any idea to fix the problem?

Thanks in advance and sorry for the code without colors.

Re: ADC random values in KL02

xiangjun_rong — Fri, 27 May 2016 10:22:39 GMT

Hi, Antonio,

I have tested the PTB0/ADC0_SE6 on my FRDM-KL02Z board, i get the same phenomenon, the ADC sample does not change no matter I test 3.3V or GND.

I will investigate the case next week.

sorry.

Xiangjun rong

Re: ADC random values in KL02

anther — Fri, 27 May 2016 11:17:36 GMT

Thank you for your reply, I've created a new thread: Possible Mask error in MKL02Z32VFG4 QFN 16 en Kinetis Microcontrollers

with new clues about this problem.

best regards.

Re: ADC random values in KL02

xiangjun_rong — Mon, 30 May 2016 02:48:32 GMT

Hi, Antoni,

As JingJing said, the ADC0_SE6(PTB0) corresponds AD9, ADCH should be 9 instead of 6, I have tested on my FRDM-KL02Z board, I can get correct result with the code by testing the PTB0 pin(pin6 of J7 on FRDM-KL02Z board):

XiangJun Rong

static int i = 0;

unsigned short sample;

int main(void)

{

/* Write your code here */

ADCInit();

/* This for loop should be replaced. By default this loop allows a single stepping. */

for (;;) {

i++;

// ADC0_CFG2&=~(0x10); //select channel a

ADC0_CFG2&=(0x10); //select channel a

ADC0_SC1A=0x09;

while(!(ADC0_SC1A&0x80)) {}

sample=ADC0_RA;

__asm("nop");

}

/* Never leave main */

return 0;

}

Re: ADC random values in KL02

anther — Mon, 30 May 2016 06:28:19 GMT

Ok XiangJun,

I've checked Jingjing reply, thank for your support.

topic ADC random values in KL02 in Kinetis Software Development Kit

ADC random values in KL02

Re: ADC random values in KL02

Re: ADC random values in KL02

Re: ADC random values in KL02

Re: ADC random values in KL02