| `timescale 1 ns / 1 ps |
| |
| module system ( |
| input clk, |
| input resetn, |
| output trap, |
| output reg [7:0] out_byte, |
| output reg out_byte_en |
| ); |
| // set this to 0 for better timing but less performance/MHz |
| parameter FAST_MEMORY = 1; |
| |
| // 4096 32bit words = 16kB memory |
| parameter MEM_SIZE = 4096; |
| |
| wire mem_valid; |
| wire mem_instr; |
| reg mem_ready; |
| wire [31:0] mem_addr; |
| wire [31:0] mem_wdata; |
| wire [3:0] mem_wstrb; |
| reg [31:0] mem_rdata; |
| |
| wire mem_la_read; |
| wire mem_la_write; |
| wire [31:0] mem_la_addr; |
| wire [31:0] mem_la_wdata; |
| wire [3:0] mem_la_wstrb; |
| |
| picorv32 picorv32_core ( |
| .clk (clk ), |
| .resetn (resetn ), |
| .trap (trap ), |
| .mem_valid (mem_valid ), |
| .mem_instr (mem_instr ), |
| .mem_ready (mem_ready ), |
| .mem_addr (mem_addr ), |
| .mem_wdata (mem_wdata ), |
| .mem_wstrb (mem_wstrb ), |
| .mem_rdata (mem_rdata ), |
| .mem_la_read (mem_la_read ), |
| .mem_la_write(mem_la_write), |
| .mem_la_addr (mem_la_addr ), |
| .mem_la_wdata(mem_la_wdata), |
| .mem_la_wstrb(mem_la_wstrb) |
| ); |
| |
| reg [31:0] memory [0:MEM_SIZE-1]; |
| initial $readmemh("firmware.hex", memory); |
| |
| reg [31:0] m_read_data; |
| reg m_read_en; |
| |
| generate if (FAST_MEMORY) begin |
| always @(posedge clk) begin |
| mem_ready <= 1; |
| out_byte_en <= 0; |
| mem_rdata <= memory[mem_la_addr >> 2]; |
| if (mem_la_write && (mem_la_addr >> 2) < MEM_SIZE) begin |
| if (mem_la_wstrb[0]) memory[mem_la_addr >> 2][ 7: 0] <= mem_la_wdata[ 7: 0]; |
| if (mem_la_wstrb[1]) memory[mem_la_addr >> 2][15: 8] <= mem_la_wdata[15: 8]; |
| if (mem_la_wstrb[2]) memory[mem_la_addr >> 2][23:16] <= mem_la_wdata[23:16]; |
| if (mem_la_wstrb[3]) memory[mem_la_addr >> 2][31:24] <= mem_la_wdata[31:24]; |
| end |
| else |
| if (mem_la_write && mem_la_addr == 32'h1000_0000) begin |
| out_byte_en <= 1; |
| out_byte <= mem_la_wdata; |
| end |
| end |
| end else begin |
| always @(posedge clk) begin |
| m_read_en <= 0; |
| mem_ready <= mem_valid && !mem_ready && m_read_en; |
| |
| m_read_data <= memory[mem_addr >> 2]; |
| mem_rdata <= m_read_data; |
| |
| out_byte_en <= 0; |
| |
| (* parallel_case *) |
| case (1) |
| mem_valid && !mem_ready && !mem_wstrb && (mem_addr >> 2) < MEM_SIZE: begin |
| m_read_en <= 1; |
| end |
| mem_valid && !mem_ready && |mem_wstrb && (mem_addr >> 2) < MEM_SIZE: begin |
| if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0]; |
| if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8]; |
| if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16]; |
| if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24]; |
| mem_ready <= 1; |
| end |
| mem_valid && !mem_ready && |mem_wstrb && mem_addr == 32'h1000_0000: begin |
| out_byte_en <= 1; |
| out_byte <= mem_wdata; |
| mem_ready <= 1; |
| end |
| endcase |
| end |
| end endgenerate |
| endmodule |