Move data from NIOS to hardware and then back to NIOS

Good catch, I never noticed that bug since I have always used the code in an infinite loop mode. I'll update the design some time this week to correct that.

I would probably make your own code to test your own hardware since most of the mSGDMA code is setup to setup random test buffers and all kinds of non-practical stuff. Your code should end up being a faction of the length if you code it for your own application. You could run an uncached malloc (see Nios II software handbook for more details) to allocate a pointer to some location in the heap and then dereference that point to populate the buffer.

Sorry I linked the wrong page, I meant this one: http://www.alterawiki.com/wiki/modular_sgdma_video_frame_buffer

If the read and write lengths are not the same then you'll need to use a pair of DMAs since a DMA typically performs the same number of reads as writes. It would be possible to hack the dispatcher HDL to support different read and write lengths but I wouldn't recommend attempting that just yet.