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Hi,
This is taken care in the project files of AN65974.
We are using Flag A to identify whether Thread 0 is ready to accept the data and Flag B to know the full condition of the DMA buffer.
You can follow the same way.
If you are already using the project files of AN65974, please check whether you are using the latest files that are available with that application note.
Thanks,
Sai Krishna.
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Hi,
"Transfer Data In" button just reads 'x' bytes of data from the USB device. 'x' is the value that you enter in the space next to "Bytes to transfer".
DMA controller present in FX3 takes care of finding a free buffer when the already allocated buffer is filled and changing the flags based on the buffer status.
Please let me know if you have any more questions on this topic.
Thanks,
Sai Krishna.
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Hi!
from AN65974 i can see that when fx3 is programmed with streaming firmware, it creates two DMA channels:
1) P2U: 16kB for USB 3.0 and the buffer count is 8
2) U2P: 16kB for USB 3.0 and the buffer count is 4
I need clarification on the following questions:
1) I always read 16kB from "Transfer data in", so the entire buffer stack is read at once.
Then I suppose that the DMA controller changes the flag A to 1 and the FPGA transfer another 16kB into the stack. With flag B on 1 (stack full condition), FX3 waits untill I press again "Transfer data in" and it starts all over again. Is it right?
2) My project need only one way data transfer, from FPGA toward FX3. Can I re-allocate the 16kB of U2P in order to have 32kB for P2U?
3) What is the buffer count?
Thank you!!
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