Latest changes

source/mojo_top.v

@@ -210,6 +210,7 @@ reg write_enable, write_enable_c_q, write_enable_c_d;
 wire[7:0] sram_read_data;
 sram #(.SIZE(8), .DEPTH(CHAR_HMAX*CHAR_VMAX)) sram(
 	.clk(hdmi_clk),
+	.rst(rst),
 	.read_address(char_index_q),
 	.write_address(addr_q-1),
 	.read_data(sram_read_data),
@@ -306,6 +307,7 @@ always @(negedge z80_ioreq) begin
 		bottom_t = 1;
 		scroll_t = scroll_q + 1;
 	end else if ((bottom_q == 1) && ((addr_t >= (scroll_q*CHAR_HMAX)) || (addr_n >= (scroll_q*CHAR_HMAX)) || (addr_r >= (scroll_q*CHAR_HMAX)))) begin
+		// Reset line
 		scroll_t = scroll_q + 1;
 	end
 
@@ -317,6 +319,7 @@ always @(negedge z80_ioreq) begin
 		addr_b = addr_b - 1;
 	end
 
+	// @todo If we underflow (-1) we do not end up in the right spot (makes sense)
 	addr_t = addr_t % (CHAR_HMAX*CHAR_VMAX);
 	addr_n = addr_n % (CHAR_HMAX*CHAR_VMAX);
 	addr_r = addr_r % (CHAR_HMAX*CHAR_VMAX);

source/sram.v

@@ -1,22 +1,27 @@
 module sram #(
-    parameter SIZE = 1,
-    parameter DEPTH = 1
-  )(
-    input clk,
-    input [$clog2(DEPTH)-1:0] read_address,
-    input [$clog2(DEPTH)-1:0] write_address,
-    output reg [SIZE-1:0] read_data,
-    input [SIZE-1:0] write_data,
-    input write_en
-  );
- 
-  reg [SIZE-1:0] ram [DEPTH-1:0];
- 
-  always @(posedge clk) begin
-    read_data <= ram[read_address];
- 
-    if (write_en)
-      ram[write_address] <= write_data;
-  end
- 
+	parameter SIZE = 1,
+	parameter DEPTH = 1
+)(
+	input clk,
+	input rst,
+	input [$clog2(DEPTH)-1:0] read_address,
+	input [$clog2(DEPTH)-1:0] write_address,
+	output reg [SIZE-1:0] read_data,
+	input [SIZE-1:0] write_data,
+	input write_en
+);
+
+reg [SIZE-1:0] ram [DEPTH-1:0];
+
+reg [DEPTH-1:0] valid;
+
+always @(posedge clk) begin
+	read_data <= ram[read_address] * valid[read_address];
+
+	if (write_en) begin
+		valid[write_address] <= 1;
+		ram[write_address] <= write_data;
+	end
+end
+
 endmodule