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PSoC™ 5, 3 & 1

MoPr_4537651
Level 4
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Level 4

Hi,

I want to interface a sdcard with the psoc5lp to store data coming in at 1Msps.

I want to do it without using the core (DMA transfers). I would also like to write to a file so that it would be easier to view the data on the laptop and process it further. PSoC creator does have the emFile component. I am unclear as to how to write to a file using DMA while using the emFile component. The emFile example given by PSoC uses the core to write values into a text file. I would like to do that using the DMA. Can someone please point me to some example code and give me some helpful pointers on how to implement this.

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Len_CONSULTRON
Level 9
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Level 9

MoPr,

Are you acquiring data using DMA?

If you can, the ping-pong DMA makes a lot of sense for the data acquisition-side.  Since you're probably using the AD4020 with SPI, you can move the 20bit results using DMA.

  • Create two large RAM buffers for your data acquisition.
  • Use two DMA TDs to move the data acquired in a ping-pong configuration.
  • Configure this DMA to provide a interrupt when a TD has completed (this buffer is full).  The next TD will start moving new acquired data into the other buffer.
  • In the ISR, perform a FS_Write() to move this buffered data into a file.  You can use another DMA TD if you want to eliminate CPU overhead for this operation.

Len

Len
"Engineering is an Art. The Art of Compromise."

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