From 3e3306bca30a4b0d57042a2b734db4d48b10154f Mon Sep 17 00:00:00 2001
From: Luca <Luca@hackerspace-bamberg.de>
Date: Sun, 29 Dec 2024 20:21:17 +0100
Subject: [PATCH] fix: pixel addressing

---
 pingxelflut.v | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/pingxelflut.v b/pingxelflut.v
index 6792abd..e45cc65 100644
--- a/pingxelflut.v
+++ b/pingxelflut.v
@@ -84,13 +84,17 @@ module pingxelflut #(
 
 	reg  [6:0] state;
 	reg        broadcast;
-	reg [22:0] pixel_addr;
+	reg [23:0] pixel_addr;
 	reg [16:0] pixel_data;
 
 	wire maybe_broadcast;
 
 	assign maybe_broadcast = broadcast && rxd == 4'hf;
 
+	wire [23:0] base_addr;
+
+	assign base_addr = pixel_addr * 3 >> 1;
+
 	initial begin
 		bus_clk <= 0;
 		bus_data <= 16'b0;
@@ -99,7 +103,7 @@ module pingxelflut #(
 
 		state <= PREAMBLE;
 		broadcast <= 0;
-		pixel_addr <= 23'b0;
+		pixel_addr <= 24'b0;
 		pixel_data <= 16'b0;
 	end
 
@@ -153,7 +157,7 @@ module pingxelflut #(
 					pixel_data[ 3:0] <= rxd;
 				end else begin
 					bus_data <= pixel_data;
-					bus_addr <= {pixel_addr, 1'b1};
+					bus_addr <= base_addr + 1;
 					bus_sel <= 2'b01;
 
 					pixel_data[11:8] <= rxd;
@@ -171,7 +175,7 @@ module pingxelflut #(
 			BLUE_LOW: begin
 				if (pixel_addr[0]) begin
 					bus_data <= pixel_data;
-					bus_addr <= {pixel_addr, 1'b0};
+					bus_addr <= base_addr + 1;
 					bus_sel <= 2'b11;
 
 					pixel_data[11:8] <= rxd;
@@ -195,10 +199,10 @@ module pingxelflut #(
 
 				if (pixel_addr[0]) begin
 					bus_clk <= 0;
-					bus_addr <= {pixel_addr, 1'b1};
+					bus_addr <= base_addr;
 					bus_sel <= 2'b10;
 				end else begin
-					bus_addr <= {pixel_addr, 1'b0};
+					bus_addr <= base_addr;
 					bus_sel <= 2'b11;
 				end
 			end
@@ -209,7 +213,7 @@ module pingxelflut #(
 			bus_clk <= 0;
 
 			state <= PREAMBLE;
-			pixel_addr <= 23'b0;
+			pixel_addr <= 24'b0;
 			pixel_data <= 16'b0;
 		end
 	end