I am implementing a radio interface for our physical layer and am integrating the FFTC into the design and would value some input on the use of linked descriptors. I am using the FFTC with host descriptors at input and output.
When operating the FFTC in FFT mode the time domain input data is stored in a circular buffer. As the system moves through the circular buffer it will hit the point where the last fragment in the buffer isn't a whole symbol length, so I need to pass a linked host descriptor A->B->NULL. Where A would be pointing to the end of the buffer and B is pointing to the beginning of the buffer. In this way I hope the QMSS will gather the memory fragments A+B and push them through the FFTC.
When operating in IFFT mode the time domain output data is stored in a circular buffer. As described above the system will move through the circular output buffer and will reach the point where the last symbol is not contiguous. Is it possible to configure the QMSS & FFTC with a pair of linked output descriptors so that the output of the IFFT output is split and placed correctly in the circular buffer?
I have examples of using the linked descriptors on the input side, does this still hold for the output side of the FFTC? Is there anything I should be wary of? The QMSS user guide leads me to think that this is possible but I wanted to run it past somebody before implementing.
Thank you
Marlon
