//==================================================================================================
//  Filename      : system_delay.v
//  Created On    : 2018-06-05 10:13:37
//  Last Modified : 2018-06-05 17:47:41
//  Revision      : 
//
//  Description   : 
//
//
//==================================================================================================

`timescale 1ns/1ns
//Delay 30ms for system stable
module system_init_delay(input clk,
					input rst_n,
					output delay_done,
					output pll_rst
					//output delay_cnt
						);

parameter SYS_DELAY_TOP=24'd256;
//delay_cnt=24'd0;
reg [24:0]delay_cnt=24'd0;
 
[email protected](posedge clk or negedge rst_n)
begin
if(!rst_n)
	delay_cnt<=0;
else if(delay_cnt<SYS_DELAY_TOP-1'b1)
		delay_cnt<=delay_cnt+1'b1;
	else
		delay_cnt<=SYS_DELAY_TOP-1'b1;
	end
assign delay_done=(delay_cnt==SYS_DELAY_TOP-1'b1)?1'b1:1'b0;
assign pll_rst=~delay_done;

endmodule // system_delay
 

//==================================================================================================
//  Filename      : system_ctrl.v
//  Created On    : 2018-06-05 10:00:38
//  Last Modified : 2018-06-05 17:49:27
//  Revision      : 
//
//  Description   : 
//
//
//==================================================================================================
//rst_n sync

`timescale 1ns/1ns
module system_ctrl (
	input clkin,    // Clock
	//input clk_en, // Clock Enable
	input rst_n,  // Asynchronous reset active low
	output sys_rst_n,
	output clk_ref,
	output delay_done
	//output [24:0]delay_cnt
);

//pll
wire locked;
sys_pll u_sys_pll (
	areset(pll_rst),
	inclk0(clkin),
	c0(clk),
	locked(locked)
	);

//wire delay_done;
reg rst_nr1,rst_nr2;
always @(posedge clk)
begin
	if(!rst_n)
	begin
		rst_nr1<=1'b0;
		rst_nr2<=1'b0;

	end
	else
	begin
		rst_nr1<=1'b1;
		rst_nr2<=rst_nr1;
	end

end

//wire delay_done;

system_init_delay #(//.SYS_DEALY_TOP(24'd2_500_000),
	.SYS_DELAY_TOP(24'd100)//for test
)
u_system_init_delay(
					.clk(clk),
					.rst_n(1'b1),
					.delay_done(delay_done)
					//.delay_cnt(delay_cnt)


					);
assign clk_ref=clk;
assign sys_rst_n=rst_nr2&pll_rst;//active high

endmodule
 

//==================================================================================================
//  Filename      : system_ctrl_TB.v
//  Created On    : 2018-06-05 10:23:49
//  Last Modified : 2018-06-05 16:40:18
//  Revision      : 
//
//  Description   : 
//
//
//==================================================================================================

`timescale 1ns/1ns

module system_ctrl_TB();
reg clk;
reg rst_n;
localparam PERIOD=2;

initial
begin 
	clk=0;
	forever #(PERIOD/2)
	clk=~clk;

end

task task_reset ();
begin
	rst_n=0;
	repeat(2)@(negedge clk);
	rst_n=1;
end
endtask


//system_ctrl_TB
wire clk_ref;
wire sys_rst_n;
wire delay_done;
//wire [24:0]delay_cnt;
system_ctrl u_system_ctrl(
				.clk(clk),
				.rst_n(rst_n),
				//output
				.clk_ref(clk_ref),
				.sys_rst_n(sys_rst_n),
				.delay_done(delay_done)
			//	.delay_cnt(delay_cnt)


	); 

//system init task
task task_sysinit;
	begin








	end
endtask

//test bench
initial
begin
	task_sysinit;
	task_reset;
	rst_n=0;
	#89;
	rst_n=1;
	#191;
	rst_n=0;
	#83;
	rst_n=1;
	#319;
	rst_n=0;
	#13;
	rst_n=1;
end

endmodule