cancel
Showing results for 
Search instead for 
Did you mean: 

PSoC™ 5, 3 & 1

Anonymous
Not applicable

Hello,

I'm trying to configure a filter with 16 bits data from an ADC DelSig. I have configured the coherency to MID in the ADC and the filter and the "dalign" is enabled in the filter. I think that I have configured the DMA properly. Howver when I see the data filtered, it have some noise. Originally I was reading a sensor wih the ADC but later I have try with a potenciometer with the same result.The noise appear when the voltage cross VDD/2. What could be the problem? Thank you

FIR900HzPot.pngFIR900HzPot2.png

FIR900HzPot.png

0 Likes
2 Replies
odissey1
Honored Contributor II

Check ADC and DMA alignment and coherency settings to this

PSoC 5LP – 16 Bit and 24 Bit Digital Filter Code Examples - Hackster.io

Secondary, avoid channel B of the Filter as it seems to have a bug in the implementation

Filter Channel B 16 bit DMA issue

0 Likes
Anonymous
Not applicable

In my project I had configured the ADC and the Filter as the follow:

ADC

  • Coherency: MID (ADC_SetCoherency(ADC1_COHER_MID)

Fiter

  • Coherency: MID (Filter_SetCoherency(Filter_CHANNEL_A, Filter_KEY_MID))
  • Dalign: Enabled (Filter_SetCoherency(Filter_CHANNEL_A, Filter_KEY_MID))

DMA

  • ADC sample pointer: ADC_DelSig_DEC_SAMP_PTR
  • Filter Stage ponter: Filter_STAGEA_PTR

This configuration is found in the components Datasheets.

The sugested project has the follow confingurarion:

ADC

  • Coherency: LOW

Fiter

  • Coherency: MID (Filter_SetCoherency(Filter_CHANNEL_A, Filter_KEY_MID))
  • Dalign: Filter_DALIGN_REG =  Filter_DALIGN_REG | FILTER_DATA_ALIGN;  with FILTER_DATA_ALIGN = 0x05

DMA

  • ADC sample pointer: ADC_DelSig_DEC_SAMP_16B_PTR
  • Filter Stage ponter: Filter_STAGEA_PTR

However i have tried with the las confiuration and I have the same result. The problem could be the imput range with the 16bits resolution?

FIR900HzPot3.png

Thank you.

0 Likes