Implementing external RAM in Nios SOPC builder

Altera_Forum · ‎11-26-2011

Hello,

I have the fpga module EP2C8Q208C8N, and try to make a SOPC module. I've succesfully made it several times on other hardware, but in this case I cannot place any more than about 4kB on-chip memory. In fact the board contain addiotional memory, which I would like to usue insted of on-chip memory, but I don't know how to implement it in SOPC builder.

Looking into documentation, I have the 23K640, "64K SPI Bus Low-Power Serial SRAM"

and

CY7C1041CV33, "4-Mbit (256K x 16) Static RAM"

Anybody could tell me, how to use it in SOPC builder?

I would be very glad for any help or clue,

best regards,

blasq

Altera_Forum · ‎11-26-2011

Hi,

If you're using Qsys, you can try the "Generic tristate controller", and adjust it with the parameters of your memory looking on its datasheet not forgetting to define it as a "memory device".

For earlier versions and without a generic controller, you should write your own wrapping into SOPC. That means that you write a verilog or VHDL file that maps the memory pins into the avalon bus, it's something like this

module    SRAM_16Bit_512K(//    Host Data
                        oDATA,iDATA,iADDR,
                        iWE_N,iOE_N,
                        iCE_N,iCLK,
                        iBE_N,
                        //    SRAM
                        SRAM_DQ,
                        SRAM_ADDR,
                        SRAM_UB_N,
                        SRAM_LB_N,
                        SRAM_WE_N,
                        SRAM_CE_N,
                        SRAM_OE_N
                        );
//    Host Side
input        iDATA;
output        oDATA;
input        iADDR;
input            iWE_N,iOE_N;
input            iCE_N,iCLK;
input        iBE_N;
//    SRAM Side
inout        SRAM_DQ;
output        SRAM_ADDR;
output            SRAM_UB_N,
                SRAM_LB_N,
                SRAM_WE_N,
                SRAM_CE_N,
                SRAM_OE_N;
assign    SRAM_DQ     =    SRAM_WE_N ? 16'hzzzz : iDATA;
assign    oDATA        =    SRAM_DQ;
assign    SRAM_ADDR    =    iADDR;
assign    SRAM_WE_N    =    iWE_N;
assign    SRAM_OE_N    =    iOE_N;
assign    SRAM_CE_N    =    iCE_N;
assign    SRAM_UB_N    =    iBE_N;
assign    SRAM_LB_N    =    iBE_N;
endmodule

Then you have to create the SOPC component that gives the _hw.tcl with "file/new component..."