diff options
Diffstat (limited to 'debouncer.v')
| -rw-r--r-- | debouncer.v | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/debouncer.v b/debouncer.v new file mode 100644 index 0000000..d37cf6d --- /dev/null +++ b/debouncer.v @@ -0,0 +1,56 @@ +module debouncer(clk_1M, rst, din, dout);
+ input clk_1M;
+ input rst;
+ input din;
+ output dout;
+
+ reg dout;
+ reg [21:0] count;
+
+ reg sync0; // first stage of synchronizer
+ reg sync1; // second stage of synchronizer
+
+ reg prev; // register for edge detection
+
+ // synchronize input. (Synchronizers will be discussed in a future lab.)
+ always @(posedge clk_1M or posedge rst) begin
+ if (rst == 1) begin
+ sync0 <= 0;
+ sync1 <= 0;
+ end
+ else begin
+ sync0 <= din;
+ sync1 <= sync0;
+ end
+ end // always
+
+ // perform an edge detect on the synchronized input.
+ always @(posedge clk_1M or posedge rst) begin
+ if (rst == 1) begin
+ prev <= 0;
+ end
+ else begin
+ prev <= sync1;
+ end
+ end // always
+
+ // state machine/counter for timing the debouncing.
+ always @(posedge clk_1M or posedge rst) begin
+ if (rst == 1) begin
+ count <= 0;
+ end
+ else begin
+ if (count == 0) begin
+ if (sync1 == 1 && prev == 0) begin // rising edge detect
+ count <= 22'd100000; // 100,000 us = 100ms delay
+ end
+ dout <= 0;
+ end
+ else begin
+ count <= count - 22'd1;
+ dout <= 1;
+ end
+ end
+ end // always
+
+endmodule
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