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How to make the ADC sampling rate of qn9080 reach 25kbps.

Question asked by zhongyi shen on Oct 29, 2019
Latest reply on Oct 31, 2019 by Estephania Martinez

How to make the ADC sampling rate of qn9080 reach 25kbps.

I read the datasheet that ADC sampling rate can reach 32kbps.

But I don't know how to set it.who can provide a example for me.

or tall me how to chage,

 

 

this is my change example code ,but it cannot reach 25Kbps

 

 

/* Configure DMA. */
DMA_Init(DMA0);
DMA_EnableChannel(DMA0, SENSOR_DMA_CHANNEL);
DMA_CreateHandle(&g_adcDmaHandle, DMA0, SENSOR_DMA_CHANNEL);
DMA_SetCallback(&g_adcDmaHandle, ADC_ConvertDMACallback, NULL);
DMA_PrepareTransfer(&transferConfig, (void *)&ADC->DATA, Adcbuff_A, sizeof(uint32_t), 1024,kDMA_PeripheralToMemory, &g_pingpong_desc[1]);
DMA_SubmitTransfer(&g_adcDmaHandle, &transferConfig);
transferConfig.xfercfg.intA = false;
transferConfig.xfercfg.intB = true;
DMA_CreateDescriptor(&g_pingpong_desc[1], &transferConfig.xfercfg, (void *)&ADC->DATA, &Adcbuff_B, &g_pingpong_desc[0]);
transferConfig.xfercfg.intA = true;
transferConfig.xfercfg.intB = false;
DMA_CreateDescriptor(&g_pingpong_desc[0], &transferConfig.xfercfg, (void *)&ADC->DATA, &Adcbuff_A,&g_pingpong_desc[1]);

 

 DMA_StartTransfer(&g_adcDmaHandle);

/**
* Initial ADC to default configuration.
*/
ADC_GetDefaultConfig(&adcConfigStruct);
adcConfigStruct.channelEnable = (1U << SENSOR_ACC_CHANNEL);
adcConfigStruct.channelConfig = (SENSOR_ADC_CFG_IDX << SENSOR_ACC_CHANNEL);
adcConfigStruct.triggerSource = kADC_TriggerSelectPWMOUT0;
adcConfigStruct.convMode = kADC_ConvModeSingle;
adcConfigStruct.clock = kADC_Clock2M;
ADC_Init(ADC, &adcConfigStruct);

/* Initial ADC Sigma Delta(SD) configuration */
ADC_GetSdDefaultConfig(&adcSdConfigStruct);
adcSdConfigStruct.downSample=kADC_DownSample32;
ADC_SetSdConfig(ADC, SENSOR_ADC_CFG_IDX, &adcSdConfigStruct);

/* Bandgap voltage */
mAdcBandgap = ADC_GetBandgapCalibrationResult(ADC, SENSOR_ADC_CFG_IDX);

/* Calibration VINN value */
mAdcVinn = ADC_GetVinnCalibrationResult(ADC, &adcConfigStruct);


/* Enable ADC */
ADC_Enable(ADC, true);

 


SCTIMER_GetDefaultConfig(&sctimerInfo);

/* Initialize SCTimer module */
SCTIMER_Init(SCT0, &sctimerInfo);

/* Configure first PWM with frequency 24kHZ from output 4 */
pwmParam.output = kSCTIMER_Out_0;
pwmParam.level = kSCTIMER_HighTrue;
pwmParam.dutyCyclePercent = 50;
if (SCTIMER_SetupPwm(SCT0, &pwmParam, kSCTIMER_CenterAlignedPwm, 25000U, CLOCK_GetFreq(kCLOCK_ApbClk), &event) == kStatus_Fail)
{
return -1;
}


/* Start the timer */
SCTIMER_StartTimer(SCT0, kSCTIMER_Counter_L);

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