epcs controller

Don't call it epcs. It is just a spi flash, you can find data and app note from stmicro.

The method to convert sof to binary data for epcs/spi flash programming is replied in another post from you.

Though your original plan is possible, it is extremely complex and slow. I would suggest another approach, control the spi flash directly. You may instant asmiblock primitive from quartus/libraries/megafunctions, which is just io pins to spi flash.

MPU SPI master -> FPGA[ --> pass through-> asmi ] -> spi flash.

wire MISO,MOSI,SCLK,SS_n;

asmiblock the_tornado_epcs_controller_atom

(

.data0out (MISO),

.dclkin (SCLK),

.oe (1'b0),

.scein (SS_n),

.sdoin (MOSI)

);