X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/06ad3a30038ac8ca45dd7b0c34213c0c8335c17c..9e1c03b633deae6254b6df312a48eba6047e266e:/Interrupt.v

diff --git a/Interrupt.v b/Interrupt.v
index 4e3d17d..201c328 100644
--- a/Interrupt.v
+++ b/Interrupt.v
@@ -13,16 +13,20 @@ module Interrupt(
 	input serial,
 	input buttons,
 	output master,
+	input ack,
 	output [7:0] jaddr);
 
 	wire [7:0] iflag = {3'b0,buttons,serial,tovf,lcdc,vblank};
 	reg [7:0] imask = 16'hFFFF;
-	reg [7:0] ihold = 0;
+	reg [7:0] ihold = 8'b0;
 	wire [7:0] imasked = ihold & imask;
+	
+	reg rdlatch = 0;
+	reg [15:0] addrlatch = 0;
 
-	assign data = rd ?
-	                 (addr == `ADDR_IF) ? ihold :
-	                 (addr == `ADDR_IE) ? imask :
+	assign data = rdlatch ?
+	                 (addrlatch == `ADDR_IF) ? ihold :
+	                 (addrlatch == `ADDR_IE) ? imask :
 	                 8'bzzzzzzzz :
 		      8'bzzzzzzzz;
 
@@ -34,17 +38,26 @@ module Interrupt(
 		       imasked[3] ? 8'h58 :
 		       imasked[4] ? 8'h60 : 8'h00;
 
-	always @ (negedge clk)
+	always @(posedge clk)
 	begin
-		if (wr) begin
+		if (wr && (addr == `ADDR_IF || addr == `ADDR_IE)) begin
 			case(addr)
 			`ADDR_IF : ihold <= iflag | data;
-			`ADDR_IE : imask <= data;
+			`ADDR_IE : begin imask <= data; ihold <= ihold | iflag; end
 			endcase
 			
-		end
+		end else if (ack)
+			ihold <= ihold &
+				(imasked[0] ? 8'b11111110 :
+				 imasked[1] ? 8'b11111101 :
+				 imasked[2] ? 8'b11111011 :
+				 imasked[3] ? 8'b11110111 :
+				 imasked[4] ? 8'b11101111 :
+				 8'b11111111);
 		else
 			ihold <= ihold | iflag;
+		rdlatch <= rd;
+		addrlatch <= addr;
 	end
 
 endmodule