can I write my own SPI interface controller in VHDL only

Hello,
I have one of Zedboard, i need to interface a external board which will be connected to the SPI interface. There are only a few input/output pins, clk, enable, data_latch, din, dout pins. Can I write my own SPI controller and using PLL to generate the 50 MHz SPI clock?  
I have no experience using the embedded on board CPU and using the SDK tool. Can I make it to work using hardware only (verilog/VHDL only) ? Since this task need to be done in a short period of time, the learning curve using the SDK and software development tool may take too long..
 
Thanks!
Sun