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// vim: ts=4 sw=4 noexpandtab
/*
* LED blinker
*
* Copyright (c) 2019 Michael Buesch <m@bues.ch>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
`ifndef LED_BLINK_MOD_V_
`define LED_BLINK_MOD_V_
module led_blink #(
parameter BLINK_ON_CLKS = 1024,
parameter BLINK_OFF_CLKS = 1024,
) (
input clk,
input n_reset,
input enable,
output reg led,
);
reg [31:0] led_on_count;
reg [31:0] led_off_count;
initial begin
led <= 0;
led_on_count <= 0;
led_off_count <= 0;
end
always @(posedge clk) begin
if (n_reset) begin
if (led) begin
if (led_on_count == 0) begin
led <= 0;
led_off_count <= BLINK_OFF_CLKS;
end else begin
led_on_count <= led_on_count - 1;
end
end else begin
if (led_off_count == 0) begin
if (enable) begin
led <= 1;
led_on_count <= BLINK_ON_CLKS;
end
end else begin
led_off_count <= led_off_count - 1;
end
end
end else begin
led <= 0;
led_on_count <= 0;
led_off_count <= 0;
end
end
endmodule
`endif /* LED_BLINK_MOD_V_ */
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