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ADC16 problem of MC56F84789

Question asked by JUN WANG on Dec 14, 2016
Latest reply on Apr 4, 2018 by Kamil Kamil

1. GPIOA11/ANC19 is the only input pin of ADC16

2.Input trans-conduct Amp shares the same VDDA of the DSC, 3.3Vdc

3. conversion time 4uS, Sample time 20=long

4.Init code:

setReg32(ADC16_SC1A, 0x1FUL);
setReg32(ADC16_SC2, 0x44UL);
setReg32(ADC16_SC3, 0x0eUL);
setReg32(ADC16_CFG1, 0x5cUL);
setReg32(ADC16_CFG2, 0x04UL);

5. Synchronous Triggered, DMA read

 

Problem:

1.After 2-10 days normal running, ADC16 result becomes noisy and unpredictable. And some fixed value like 0x07f7 or 0x1ff7 may come out frequently.(input amp and signal source are checked OK)

2. Meanwhile, other analog parts of the DSC such as ADC12 and DAC12 or Comparators work well.

3. Till now, there are at least 5 DSCs suffered from the same problem one by one.

 

Help please!

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