2016-10-06 09:53 PM
I tied the ADC in to GND, make the ADC DMA work normal mode, what ever I change the transfer size, the nois is big different just in the middle.
Crazzy!!!Data shows in the figure is 16bit AD1,AD2,AD1,AD2...../*ADC configed multi-mode*/ multimode.Mode = ADC_DUALMODE_REGSIMULT; multimode.DMAAccessMode = ADC_DMAACCESSMODE_2; multimode.TwoSamplingDelay = ADC_TWOSAMPLINGDELAY_5CYCLES; HAL_ADCEx_MultiModeConfigChannel(&Adc1Handle, &multimode); HAL_ADCEx_MultiModeConfigChannel(&Adc2Handle, &multimode);2016-10-06 10:17 PM
This is two ADC's sepreat display.
2016-10-06 10:34 PM
Samples at 1MHz, total ADC time was tested by a timer is 1024*3 uS, so the sample point is correct.
I think the problem reason is the DMA config, need some times to understand! Tie ADC1 to VCC, ADC2 to GND, and memset all data to 0, now the figure is:2016-10-10 09:29 AM
Hi qiyong.mu.001,
The noise may come from spurious charge shots out of AD inputs. Try to eliminate that with the using of ''Averaging'' or ''Digital-signal filtering'' methods described in the application note ''How to get the best ADC accuracy in STM32Fx Series and STM32L1 Series devices'' (page 22 and page 32)-Hannibal-