From 1525373c611bc3a7fef1deb1eefd34ec154ff106 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jose=20Luis=20Monta=C3=B1es=20Ojados?=
 <joseluis@greenest.ai>
Date: Sun, 1 Mar 2026 01:21:07 +0100
Subject: [PATCH] add flipflop

---
 flip_flop/flip_flop.v    | 17 +++++++++++++
 flip_flop/flip_flop_tb.v | 52 ++++++++++++++++++++++++++++++++++++++++
 roadmap.md               |  2 +-
 3 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 flip_flop/flip_flop.v
 create mode 100644 flip_flop/flip_flop_tb.v

diff --git a/flip_flop/flip_flop.v b/flip_flop/flip_flop.v
new file mode 100644
index 0000000..b7f7fcd
--- /dev/null
+++ b/flip_flop/flip_flop.v
@@ -0,0 +1,17 @@
+/*
+    Flip-Flop D y registro
+*/
+
+module register #(parameter N = 8)(
+    input clk,
+    input rst,
+    input en,
+    input [N-1:0] d,
+    output reg [N-1:0] q
+);
+    always @(posedge clk or posedge rst) begin
+        if (rst) q <= 0;
+        else if (en) q <= d;
+    end
+
+endmodule
\ No newline at end of file
diff --git a/flip_flop/flip_flop_tb.v b/flip_flop/flip_flop_tb.v
new file mode 100644
index 0000000..7c69104
--- /dev/null
+++ b/flip_flop/flip_flop_tb.v
@@ -0,0 +1,52 @@
+/*
+    Flip-Flop D y registro
+*/
+`include "./flip_flop/flip_flop.v"
+
+module register_tb;
+    reg clk, rst, en;
+    reg [7:0] d;
+    wire [7:0] q;
+
+    register #(.N(8)) dut (
+        .clk(clk),
+        .rst(rst),
+        .en(en),
+        .d(d),
+        .q(q)
+    );
+
+    initial clk = 0;
+    always #5 clk = ~clk;
+
+    initial begin
+        $dumpfile("./flip_flop/flip_flop.vcd");
+        $dumpvars(0, register_tb);
+
+        rst = 1; en = 0; d = 0;
+        @(posedge clk); #1
+
+        rst = 0;
+        @(posedge clk); #1
+        $display("rst=0, en=0, d=%0d, q=%0d (q no cambia)", d, q);
+
+        en = 1; d = 8'd42;
+        @(posedge clk); #1
+        $display("en=1, d=42 → q=%0d", q);
+
+        d = 8'd99;
+        @(posedge clk); #1
+        $display("en=1, d=99 → q=%0d", q);
+
+        en = 0; d = 8'd7;
+        @(posedge clk); #1
+        $display("en=0, d=7  → q=%0d (q mantiene 99)", q);
+
+        rst = 1;
+        @(posedge clk); #1
+        $display("rst=1      → q=%0d (q=0)", q);
+
+        $finish;
+    end
+
+endmodule
\ No newline at end of file
diff --git a/roadmap.md b/roadmap.md
index 5f9c2ce..57f25ac 100644
--- a/roadmap.md
+++ b/roadmap.md
@@ -347,7 +347,7 @@ gtkwave modulo.vcd
 - [x] Fase 1.3 — ALU basica
 - [x] Fase 1.4 — Mux / Demux
 - [x] Fase 1.5 — Decoder / Encoder
-- [ ] Fase 2.1 — Flip-Flop D y registro
+- [x] Fase 2.1 — Flip-Flop D y registro
 - [ ] Fase 2.2 — Contador
 - [ ] Fase 2.3 — Shift Register
 - [ ] Fase 2.4 — Register File