Use ctlr slv address instead of record address. Separate p_burst_size into wr and rd process and define burstsize as positive. Assign ctlr_mosi.burstsize directly using wr/rd_burst_size, no need for ctlr_mosi_burstsize.

Ported $UNB ddr3.vhd to $RADIOHDL io_ddr.vhd. Initial version, still needs to be compiled and simulated with tb_io_ddr.vhd.