Writing to SRAM from VHDL and using NIOS

Dear All,

For a schoolproject I am working on a spectrum analyzer. I have downloaded the Altera University program and I modified de C code so it will display a nice coordinate system. Outside NIOS I programmed a FFT in VHDL with input from an external ADC. So far this all works.

What I want to do now is build a bar graph. I would like to write this directly to the SRAM from VHDL but this is already occupied by NIOS. So I understand I now need to make a custom peripheral to acces this SRAM from VHDL but I can't figure out how. I do understand VHDL but all things that have to do with NIOS and SOPC are completely strange to me.

Please give me some tips.