Best way for adc speed increasing in k22 mcu?

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Best way for adc speed increasing in k22 mcu?

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mangramarco
Contributor III

What is faster adc conversion methods?

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danielchen
NXP TechSupport
NXP TechSupport

Just add to Mark's good explanation, there is also an adc with edma demo in MCUXpresso SDK.

SDK_2.4.1_FRDM-K22F\boards\frdmk22f\driver_examples\adc16\continuous_edma

Regards

Daniel

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mangramarco
Contributor III

Thank you!

DMA can increase speed of adc data transmission??

What is the best way for increase data transmission speed??

Best regards

Marco

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mjbcswitzerland
Specialist V

Hi Marco

The ADC conversion time is one aspect (as described) but the second aspect is using the data.

DMA can be used to save the samples to a circular buffer for subsequent firmware analysis or passing to other interfaces.

The uTasker project contains a turn-key reference that allows sampling an ADC input at > 400kHz to a circular buffer via DMA, transferring the signal to the DAC output (after a delay) and perform an FFT in the buffer. This shows that the K22F can achieve an FFT on a 200kHz bandwidth with frequency resolution of about 100Hz with a new result every 10ms using 50% of its CPU power.

There is also a reference via USB (which doesn't use the ADC but the principle is the same if USB is considered as a sampled digital analoge input) at https://www.youtube.com/watch?v=n-GABeILGV8&feature=youtu.be

Regards

Mark

Kinetis: http://www.utasker.com/kinetis.html
Kinetis K22:
- http://www.utasker.com/kinetis/FRDM-K22F.html
- http://www.utasker.com/kinetis/TWR-K22F120M.html
- http://www.utasker.com/kinetis/BLAZE_K22.html
- http://www.utasker.com/kinetis/tinyK22.html

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mjbcswitzerland
Specialist V

Marco

Single-ended, lower resolution, fastest allowed ADC clock, no HW averaging and all settings set to minimum delays: Single conversion time around 1.24us / subsequent conversion times about 865ns

Regards

Mark