RISCV_SOC.v

//=======================================================
//  This code is generated by Terasic System Builder
//=======================================================

module RISCV_SOC(
	input 		          		CLOCK_50,
	input 		     [3:0]		KEY,
	output reg		  [9:0]		LEDR,
	output		     [7:0]		VGA_B,
	output		          		VGA_BLANK_N,
	output		          		VGA_CLK,
	output		     [7:0]		VGA_G,
	output		          		VGA_HS,
	output		     [7:0]		VGA_R,
	output		          		VGA_SYNC_N,
	output		          		VGA_VS
);



//=======================================================
//  REG/WIRE declarations
//=======================================================

	
	/*wire [31:0] data;
	assign HEX0 = data[7:0];
	assign HEX1 = data[14:8];
	assign HEX2 = data[21:15];
	assign HEX3 = data[28:22];
	assign HEX4 = data[31:29];*/

	//soctop st(.clk(CLOCK_50), .reset(KEY[0]), .do(data));
//=======================================================
//  Structural coding
//=======================================================
    wire [31:0] cpuDataOut;
    wire [31:0] busAddress;
    wire        busWriteEnable;
    
    assign do = busAddress;
	 
	 // MEMORY MAP
	 // 0000_0000h - 000F_FFFF ROM 1MB max
	 // 0010_0000h - 001F_FFFF RAM 1MB max
	 // 0020_0000h - 002F_FFFF VRAM 1MB max
	 // 8000_0000h - 8000_0FFF IO
	 wire ioSelect  = busAddress[31];
	 wire gpuSelect  = busAddress[21];
	 wire romSelect = ~busAddress[20];
	 wire ramSelect = busAddress[20];
	 
	 
	 wire [31:0] ramDataOut;
	 wire [31:0] romDataOut;
	 wire [31:0] gpuDataOut;
	 
	 wire clk = CLOCK_50;
	 reg [31:0] ioDataOut;
	 
	 wire [31:0] busDataIn = ioSelect ? ioDataOut :
									 gpuSelect ? gpuDataOut :
									 ramSelect ? ramDataOut :
									 romDataOut;
									 
									 
	 
	 always @(posedge clk)
	 begin
		if (ioSelect)
		begin
			if (busWriteEnable)
				LEDR <= cpuDataOut[9:0];
			else
				ioDataOut <= LEDR;
		end
	 end
	 
	GPU gpu(
		.clk(clk),
		.enable(gpuSelect),
		.busAddress(busAddress[17:1]),
		.busWriteEnable(busWriteEnable),
		.busDataOut(gpuDataOut),
		.busDataIn(cpuDataOut),
		
		.VGA_B(VGA_B),
		.VGA_BLANK_N(VGA_BLANK_N),
		.VGA_CLK(VGA_CLK),
		.VGA_G(VGA_G),
		.VGA_HS(VGA_HS),
		.VGA_R(VGA_R),
		.VGA_SYNC_N(VGA_SYNC_N),
		.VGA_VS(VGA_VS)
	);
	
	 ROM rom(
        .clk(clk),
		  .enable(romSelect),
        .address({ 12'b0, busAddress[19:0] }),
        .dataIn(cpuDataOut),
        .dataOut(romDataOut)
    );
	 
    RAM ram(
        .clk(clk),
		  .enable(ramSelect),
        .address({ 12'b0, busAddress[19:0] }),
        .dataIn(cpuDataOut),
        .writeEnable(busWriteEnable),
        .dataOut(ramDataOut)
    );
        
    RISCV cpu(
        .clk(clk),
        .reset(~KEY[0]),
        .dataIn(busDataIn),
        .dataOut(cpuDataOut),
        .address(busAddress),
        .writeEnable(busWriteEnable)
    );



endmodule