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FX3 transfers seems to be losing data | Cypress Semiconductor

FX3 transfers seems to be losing data

Summary: 1 Reply, Latest post by PRAG on 27 Oct 2014 07:19 AM PDT
Verified Answers: 0
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CZL's picture
5 posts

Apologies, posted this to the wrong subforum first time.

I am wiring up an embedded device to trasmit data via the FX3 to a PC.  I'm using pretty much a stock SlaveFifoSync.img from the examples in the development kit, and the GPIF interface.  I'm transmitting 16 bits per PCLK toggle.

My data comes from reading a 16-bit ADC.  I end up with 2048 ADC reads per data packet, ie 4096 bytes of date per packet.

I figure I *should* be able to just put the data on the data lines, then toggle PCLK to load it, repeat that 2048 times, then terminate the transfer with a PKTEND toggle.


But I lose data.  The content is obviously there, but it's not in the right place.


If I add some dummy PCLK toggles, and by some I mean 12 at the front and 88 at the back of each toggle, everything I get lines up nicely, but I end up missing some samples in there.


What I'm thinking is that even though I'm doing a 4096 byte transfer, what's actually happneing is about four 1024 transfers (size of the xmit buffer in the config I have), and that there are some expected header bytes, or possibly some delays that the extra PCLK toggles are making up for.


I have read the documentation, but I'm obviously missing something.  Would greatly appreciate input.


Thank you,



PRAG's picture
Cypress Employee
173 posts

 This is a duplicate thread to the one seen here:

We can continue to discuss on that thread.

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