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<span class="hljs-meta">`<span class="hljs-meta-keyword">timescale</span> 1ns / 1ps</span>
<span class="hljs-comment">/**
* counter: a generic clearable up-counter
*/</span>
<span class="hljs-keyword">module</span> counter
#(<span class="hljs-keyword">parameter</span> WIDTH=<span class="hljs-number">64</span>)
(
<span class="hljs-keyword">input</span> clk,
<span class="hljs-keyword">input</span> ce,
<span class="hljs-keyword">input</span> arst_n,
<span class="hljs-keyword">output</span> <span class="hljs-keyword">reg</span> [WIDTH-<span class="hljs-number">1</span>:<span class="hljs-number">0</span>] q
);
<span class="hljs-comment">// some child</span>
clock_buffer <span class="hljs-variable">#(WIDTH)</span> buffer_inst (
<span class="hljs-variable">.clk</span>(clk),
<span class="hljs-variable">.ce</span>(ce),
<span class="hljs-variable">.reset</span>(arst_n)
);
<span class="hljs-comment">// Simple gated up-counter with async clear</span>
<span class="hljs-keyword">always</span> @(<span class="hljs-keyword">posedge</span> clk <span class="hljs-keyword">or</span> <span class="hljs-keyword">negedge</span> arst_n) <span class="hljs-keyword">begin</span>
<span class="hljs-keyword">if</span> (arst_n == <span class="hljs-number">1'b0</span>) <span class="hljs-keyword">begin</span>
q <= {WIDTH {<span class="hljs-number">1'b0</span>}};
<span class="hljs-keyword">end</span>
<span class="hljs-keyword">else</span> <span class="hljs-keyword">begin</span>
q <= q;
<span class="hljs-keyword">if</span> (ce == <span class="hljs-number">1'b1</span>) <span class="hljs-keyword">begin</span>
q <= q + <span class="hljs-number">1</span>;
<span class="hljs-keyword">end</span>
<span class="hljs-keyword">end</span>
<span class="hljs-keyword">end</span>
<span class="hljs-keyword">endmodule</span>
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