Another minor step towards pynq on the RedPitaya control system.  Here is the result of uploading an arbitrary wave form, playing it, and reading it back.  This is the demo described here:  https://github.com/dspsandbox/FPGA-Notes-for-Scientists/wiki/DMA-transfer

One vhdl bug had to be fixed, putting a 0 value in quotes to help the compiler.  Vivado compilers are more careful now about types.