Data acquisition to SD card with IMX RT

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Data acquisition to SD card with IMX RT

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lacouturepatric
Contributor I
Hello,
I am working on a project of data acquisition. I am looking for the possibilities of using an i.MX RT familly for my project.  

My need is that I must store data continuously from ADC into a micro SD card. The ADC delivers 2 bits or 4 bits and a clock at 25 MHz.
I have the following questions.
1) For the acquisition part, should I used the flexio interface or CMOS Sensor Interface (exemple AN12110) ?
2) Do I need an EDMA and SRAM between the acquisition part and the uSDHC.
3) According to the IXM Reference Manual, the features of the uSDHC module can include "Card bus clock frequency up to 208 MHz" (SDR104 mode).
Do I need only to power the micro SD card (UHS I) at 1.8V and use analog buffer (3V3 / 1.8V) for driving the uSDHC pin (4 data, clock, cmd) ?
Note : IMX user IO will be drived at 3V3
Thank you,
Best Regards
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lacouturepatric
Contributor I

Ok thank you very much for your help.

Best regards,

Patrice Lacouture

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lacouturepatric
Contributor I

Hello Jorge Alcala,

Thank you very much for your answers.

For the acquisition part, I will use the flexio.

Do you know the maximum input external clock supported by the flexio peripheral for IM RT 1050/ 1060 and 1064 (flexio used for sampling with external clock)?

Thank you,

Best regards

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jorge_a_vazquez
NXP Employee
NXP Employee

Hi Lacouture Patrice

You can find in the Reference Manual the following table:

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Hope it helps

Best regards

Jorge Alcala

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jorge_a_vazquez
NXP Employee
NXP Employee

Hi Lacouture Patrice

1) For the acquisition part, should I used the flexio interface or CMOS Sensor Interface (exemple AN12110) ?
This depends on the ADC device that you are using, my recommendation for this case is the flexio.

2) Do I need an EDMA and SRAM between the acquisition part and the uSDHC.
This also depends on you, unfortunately, there isn't any demo with sdcard that uses DMA, but there is already some demo with FatFS system, or only with interrupt mode.

3) According to the IXM Reference Manual, the features of the uSDHC module can include "Card bus clock frequency up to 208 MHz" (SDR104 mode).
Do I need only to power the micro SD card (UHS I) at 1.8V and use analog buffer (3V3 / 1.8V) for driving the uSDHC pin (4 data, clock, cmd) ?
Yes, you can use the VSELECT pin to communicate with the external deviceto switch the voltage.
Hopet his information helps
Best regards
Jorge Alcala
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