NFC read pipelining example?

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NFC read pipelining example?

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bowerymarc
Contributor V

Are there any examples of using the Nand Flash Controller for continuous pipelined reads, including DMA?  There are some vague  examples of pipelining commands in the manual and AN4348 to different buffers in the NFC but nothing connecting DMA.

The idea is to stream data off the NAND flash as fast as possible into user memory. From the description the NFC can, in parallel, read a page from NAND into a buffer, perform ECC on a different buffer, and DMA yet a third buffer.  But I don't get how to do that, since there is no separate interrupt trigger for DMA complete.  There's only a command complete, and IDLE (which states it's command complete AND ECC complete AND DMA complete). But if you are constantly new issuing commands from the command complete interrupt, you'll never get an IDLE interrupt to tell when your DMA is complete so you can set the DMA to service the next buffer.  Or am I missing something?

It seems like the only way to do that is either not use the DMA and have the processor move the data out of the NFC buffer, or use the eDMA controller as a data mover, and use it's done interrupts to tell when your data is moved and ready to use. 

Otherwise I don't see how to pipeline....

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perlam_i_au
Senior Contributor I

Could you please tell me what part number are you using?

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bowerymarc
Contributor V

K20F120 and K60F120.

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Carlos_Musich
NXP Employee
NXP Employee


Hi Marc,

This is a not very common technical issue. Can you please submit a Service Request at www.freescale.com/support?

Best regards,

Carlos

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bowerymarc
Contributor V

it's not common because there is no code anywhere that illustrates this ability that is claimed in the reference manual.  There is no illustration of the timing of the pipeline, or explanation of the 'residue engine', etc.  I also find it disheartening that the reference manual talks about EDO timing, when the fastest available K20/K60 parts, in the part data sheet, state the max speed for the NFC is 25MHz, far short of the speed required for EDO.  Very misleading.

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