From df3a74798e1db0bd2c7b45931fd6fa98ed80eba7 Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@linux.ibm.com>
Date: Sun, 2 Feb 2020 09:02:33 +1100
Subject: [PATCH] Add a parameter to control the polarity of reset

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
---
 toplevel.v | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/toplevel.v b/toplevel.v
index f3738f9..9f0977d 100644
--- a/toplevel.v
+++ b/toplevel.v
@@ -1,4 +1,6 @@
-module toplevel(
+module toplevel #(
+	parameter RESET_LOW = 1
+) (
 	input clock,
 	input reset,
 	output io_tx,
@@ -32,7 +34,7 @@ reg [21:0] cnt = ~0;
 
 always@(posedge clock)
 begin
-	if (~lock || ~reset)
+	if (~lock || (reset ^ RESET_LOW))
 	begin
 		cnt <= ~0;
 	end