| // OpenRAM SRAM model |
| // Words: 512 |
| // Word size: 32 |
| // Write size: 8 |
| |
| module sky130_sram_2kbyte_1rw1r_32x512_8( |
| `ifdef USE_POWER_PINS |
| vccd1, |
| vssd1, |
| `endif |
| // Port 0: RW |
| clk0,csb0,web0,wmask0,addr0,din0,dout0, |
| // Port 1: R |
| clk1,csb1,addr1,dout1 |
| ); |
| |
| parameter NUM_WMASKS = 4 ; |
| parameter DATA_WIDTH = 32 ; |
| parameter ADDR_WIDTH = 9 ; |
| parameter RAM_DEPTH = 1 << ADDR_WIDTH; |
| // FIXME: This delay is arbitrary. |
| parameter DELAY = 3 ; |
| parameter VERBOSE = 0 ; //Set to 0 to only display warnings |
| parameter T_HOLD = 1 ; //Delay to hold dout value after posedge. Value is arbitrary |
| |
| `ifdef USE_POWER_PINS |
| inout vccd1; |
| inout vssd1; |
| `endif |
| input clk0; // clock |
| input csb0; // active low chip select |
| input web0; // active low write control |
| input [NUM_WMASKS-1:0] wmask0; // write mask |
| input [ADDR_WIDTH-1:0] addr0; |
| input [DATA_WIDTH-1:0] din0; |
| output [DATA_WIDTH-1:0] dout0; |
| input clk1; // clock |
| input csb1; // active low chip select |
| input [ADDR_WIDTH-1:0] addr1; |
| output [DATA_WIDTH-1:0] dout1; |
| |
| reg csb0_reg; |
| reg web0_reg; |
| reg [NUM_WMASKS-1:0] wmask0_reg; |
| reg [ADDR_WIDTH-1:0] addr0_reg; |
| reg [DATA_WIDTH-1:0] din0_reg; |
| reg [DATA_WIDTH-1:0] dout0; |
| |
| // All inputs are registers |
| always @(posedge clk0) |
| begin |
| csb0_reg = csb0; |
| web0_reg = web0; |
| wmask0_reg = wmask0; |
| addr0_reg = addr0; |
| din0_reg = din0; |
| #(T_HOLD) dout0 = 32'bx; |
| if ( !csb0_reg && web0_reg && VERBOSE ) |
| $display($time," Reading %m addr0=%b dout0=%b",addr0_reg,mem[addr0_reg]); |
| if ( !csb0_reg && !web0_reg && VERBOSE ) |
| $display($time," Writing %m addr0=%b din0=%b wmask0=%b",addr0_reg,din0_reg,wmask0_reg); |
| end |
| |
| reg csb1_reg; |
| reg [ADDR_WIDTH-1:0] addr1_reg; |
| reg [DATA_WIDTH-1:0] dout1; |
| |
| // All inputs are registers |
| always @(posedge clk1) |
| begin |
| csb1_reg = csb1; |
| addr1_reg = addr1; |
| // if (!csb0 && !web0 && !csb1 && (addr0 == addr1)) |
| // $display($time," %m\n, WARNING: Writing and reading addr0=%b and addr1=%b simultaneously!",addr0,addr1); |
| #(T_HOLD) dout1 = 32'bx; |
| if ( !csb1_reg && VERBOSE ) |
| $display($time," Reading %m addr1=%b dout1=%b",addr1_reg,mem[addr1_reg]); |
| end |
| |
| reg [DATA_WIDTH-1:0] mem [0:RAM_DEPTH-1]; |
| |
| // Memory Write Block Port 0 |
| // Write Operation : When web0 = 0, csb0 = 0 |
| always @ (negedge clk0) |
| begin : MEM_WRITE0 |
| if ( !csb0_reg && !web0_reg ) begin |
| if (wmask0_reg[0]) |
| mem[addr0_reg][7:0] = din0_reg[7:0]; |
| if (wmask0_reg[1]) |
| mem[addr0_reg][15:8] = din0_reg[15:8]; |
| if (wmask0_reg[2]) |
| mem[addr0_reg][23:16] = din0_reg[23:16]; |
| if (wmask0_reg[3]) |
| mem[addr0_reg][31:24] = din0_reg[31:24]; |
| end |
| end |
| |
| // Memory Read Block Port 0 |
| // Read Operation : When web0 = 1, csb0 = 0 |
| always @ (negedge clk0) |
| begin : MEM_READ0 |
| if (!csb0_reg && web0_reg) |
| dout0 <= #(DELAY) mem[addr0_reg]; |
| end |
| |
| // Memory Read Block Port 1 |
| // Read Operation : When web1 = 1, csb1 = 0 |
| always @ (negedge clk1) |
| begin : MEM_READ1 |
| if (!csb1_reg) |
| dout1 <= #(DELAY) mem[addr1_reg]; |
| end |
| |
| endmodule |