Hardware Trigger for Sigma Delta ADC with eTPU

[berat24]

Hello there,

I would like to trigger Sigma Delta ADC through eTPUA channel 20. My aim is to obtain 50 kHZ sampling time for SDADC with the help of eTPU. Do I have to use match and capture registers to do this as well as time base registers or Could I set a basic timer with eTPU in order to have 50 kHZ sampling time for SDADC without match and compare registers. (it is equal to 20us).

I hope, I could explain my question totally.

Thanks in advance to all NXP professional.

[davidtosenovjan]

I made example here for triggering of SDADC by eTPU here:
https://community.nxp.com/docs/DOC-335360

However consider whether you don't need rather to use eQADC module as once enabled the SDADC keeps running. There is no “Single conversion mode”.
This requires that the CDATA register be continually drained by DMA or ISR. The digital nature of the SDADC means that there is a propagation delay as the data is clocked through the internal digital filters. This has to be taken into account at startup or at any channel mux change. This latency means that the SDADC is not well suited to some applications including motor control. When used in an AC sampling application it is likely that each SDADC will have to be dedicated to a particular input rather than switching the input channel.

SDADC is always combined with other type of ADC, on this device it is eQADC offering advanced triggering capability (on other MPC57xx device SDADC is supplemented by SAR ADC).

[davidtosenovjan]

Hi, could you specify used device?

[berat24]

@davidtosenovjan I am sorry. I am using MCP5777C.