X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/6ba4cfea4b24fdd898e90ebd55e95ad43d5d21d4..3a0bde75799d99fe866e3afe14a0302ffe4e66a5:/Sound2.v

diff --git a/Sound2.v b/Sound2.v
index fa5e5e7..ef38263 100644
--- a/Sound2.v
+++ b/Sound2.v
@@ -16,7 +16,7 @@ module Sound2(
 	);
 
 	/* can be optimized as register file */
-	reg [7:0] nr21, nr22, nr23, nr24;
+	reg [7:0] nr21 = 0, nr22 = 0, nr23 = 0, nr24 = 0;
 	reg [10:0] counter = 0;
 	reg [4:0] lencnt = 0;
 	reg [3:0] delta = 4'b1111;
@@ -24,15 +24,20 @@ module Sound2(
 	reg [3:0] snd_out = 0;
 
 	assign snd_data = en ? snd_out : 0;
+	
+	reg rdlatch;
+	reg [15:0] addrlatch;
 
-	assign data = rd ?
-	                 addr == `ADDR_NR21 ? nr21 :
-	                 addr == `ADDR_NR22 ? nr22 :
-	                 addr == `ADDR_NR23 ? nr23 :
-	                 addr == `ADDR_NR24 ? nr24 : 8'bzzzzzzzz
+	assign data = rdlatch ?
+	                 addrlatch == `ADDR_NR21 ? nr21 :
+	                 addrlatch == `ADDR_NR22 ? nr22 :
+	                 addrlatch == `ADDR_NR23 ? nr23 :
+	                 addrlatch == `ADDR_NR24 ? nr24 : 8'bzzzzzzzz
 	              : 8'bzzzzzzzz;
 
-	always @ (negedge core_clk) begin
+	always @ (posedge core_clk) begin
+		rdlatch <= rd;
+		addrlatch <= addr;
 		if(en && wr) begin
 			case(addr)
 			`ADDR_NR21: nr21 <= data;