wb_slv_model.v

USB_I2C_MAC_FPGA_Code.rar

`include "wb_model_defines.v"

module wb_slv(clk, rst, adr, din, dout, cyc, stb, sel, we, ack, err, rty);

input		clk, rst;
input	[31:0]	adr, din;
output	[31:0]	dout;
input		cyc, stb;
input	[3:0]	sel;
input		we;
output		ack, err, rty;

////////////////////////////////////////////////////////////////////
//
// Local Wires
//

parameter	mem_size = 13;
parameter	sz = (1<<mem_size)-1;

reg	[31:0]	mem[sz:0];
wire		mem_re, mem_we;
wire	[31:0]	tmp;
reg	[31:0]	dout, tmp2;

reg		ack, err, rty;
reg	[31:0]	del_ack;
reg	[5:0]	delay;

////////////////////////////////////////////////////////////////////
//
// Memory Logic
//

initial
   begin
	delay = 0;
	ack = 0;
	err = 0;
	rty = 0;
	#2;
	$display("\nINFO: WISHBONE MEMORY MODEL INSTANTIATED (%m)");
	$display("      Memory Size %0d address lines %0d words\n",
		mem_size, sz+1);
   end

assign mem_re = cyc & stb & !we;
assign mem_we = cyc & stb &  we;

assign	tmp = mem[adr[mem_size+1:2]];

always @(sel or tmp or mem_re or ack)
	if(mem_re & ack)
	   begin
		dout[31:24] <= #1 sel[3] ? tmp[31:24] : 8'hxx;
		dout[23:16] <= #1 sel[2] ? tmp[23:16] : 8'hxx;
		dout[15:08] <= #1 sel[1] ? tmp[15:08] : 8'hxx;
		dout[07:00] <= #1 sel[0] ? tmp[07:00] : 8'hxx;
	   end
	else	dout <= #1 32'hzzzz_zzzz;


always @(sel or tmp or din)
   begin
	tmp2[31:24] = !sel[3] ? tmp[31:24] : din[31:24];
	tmp2[23:16] = !sel[2] ? tmp[23:16] : din[23:16];
	tmp2[15:08] = !sel[1] ? tmp[15:08] : din[15:08];
	tmp2[07:00] = !sel[0] ? tmp[07:00] : din[07:00];
   end

always @(posedge clk)
	if(mem_we)	mem[adr[mem_size+1:2]] <= #1 tmp2;

always @(posedge clk)
	del_ack = ack ? 0 : {del_ack[30:0], cyc & stb};

always	ack = #1 cyc & stb & ((delay==0) ? 1'b1 : del_ack[delay-1]);


task fill_mem;
input mode;
integer n, mode;

begin
for(n=0;n<(sz+1);n=n+1)
   begin
	case(mode)
	   0:	mem[n] = { ~n[15:0], n[15:0] };
	   1:	mem[n] = $random;
	   2:	mem[n] = { n[5:0], 2'h3, n[5:0], 2'h2, n[5:0], 2'h1, n[5:0], 2'h0};
	endcase
   end
end
endtask

task set_delay;
input dly;

reg [5:0] dly;
begin
    delay = dly;
    $display("\n INFO: WISHBONE MEMORY MODEL (%M)");
    $display("       Delay set to %d\n", delay);
end
endtask

endmodule