From 6001db94b7d15e097001a3e4e8b4ea1eaee75bad Mon Sep 17 00:00:00 2001
From: Alexander Oh <oh.a@gmx.at>
Date: Thu, 27 May 2010 03:34:59 +0200
Subject: [PATCH] cleanup pc communication

---
 src/beh_pc_communication_tb.vhd |  1 -
 src/pc_communication.vhd        | 47 +++++++++++++--------------------
 2 files changed, 19 insertions(+), 29 deletions(-)

diff --git a/src/beh_pc_communication_tb.vhd b/src/beh_pc_communication_tb.vhd
index bdce739..03d1d62 100644
--- a/src/beh_pc_communication_tb.vhd
+++ b/src/beh_pc_communication_tb.vhd
@@ -117,7 +117,6 @@ begin
 		-- we only simulate pressing of button a by now!
 		sys_res_n <= '0';
 		btn_a <= '0';
-		tx_data <= ( others => '0');
 		rx_data <= ( others => '0');
 		rx_new <= '0';
 		
diff --git a/src/pc_communication.vhd b/src/pc_communication.vhd
index 610ec68..321d0a3 100644
--- a/src/pc_communication.vhd
+++ b/src/pc_communication.vhd
@@ -32,15 +32,12 @@ end entity pc_communication;
 architecture beh of pc_communication is
 	signal spalte, spalte_next : integer range 1 to hspalte_max + 1;
 	signal zeile , zeile_next : integer range 1 to hzeile_max + 1;
-	signal spalte_up, spalte_up_next : std_logic;
 	signal get, get_next : std_logic;
 	signal new_i, new_i_next : std_logic;
 	signal tx_done_i, tx_done_i_next : std_logic;
 	signal tx_data_i, tx_data_i_next : std_logic_vector (7 downto 0);
 	signal s_done, s_done_next : std_logic;
 
-	signal char, char_next : hbyte;
-	signal char_en : std_logic;
 	type STATE_PC is (IDLE, FETCH, FORWARD, DONE);
 	signal state, state_next : STATE_PC ;
 
@@ -50,7 +47,6 @@ begin
 	d_zeile <= hzeile(std_logic_vector(to_unsigned(zeile,7)));
 	d_spalte <= hspalte(std_logic_vector(to_unsigned(spalte,7)));
 	d_get <= get;
-	char_next <= d_char;
 	tx_new <= new_i;
 	tx_done_i_next <= tx_done;
 	tx_data <= tx_data_i;
@@ -64,7 +60,6 @@ begin
 			get <= '0';
 			new_i <= '0';
 			tx_data_i <= "00000000";
-			spalte_up <= '0';
 			tx_done_i <= '0';
 			s_done <= '0';
 		elsif rising_edge(sys_clk) then
@@ -75,25 +70,37 @@ begin
 			new_i <= new_i_next;
 			tx_done_i <= tx_done_i_next;
 			tx_data_i <= tx_data_i_next;
-			spalte_up <= spalte_up_next;
 			s_done <= s_done_next;
-			if (char_en = '1') then
-				char <= char_next;
-			end if;
 		end if;
 	end process sync;
 
-	output_pc : process (state, zeile, spalte, char, tx_data_i, tx_done_i, spalte_up)
+	output_pc : process (state, zeile, spalte, tx_data_i, tx_done_i)
+	variable spalte_up : std_logic;
 	begin
 		get_next <= '0';
 		new_i_next <= '0';
 
-		spalte_up_next <= '0';
 		s_done_next <= '0';
 		spalte_next <= spalte;
 		zeile_next <= zeile;
 		tx_data_i_next <= tx_data_i;
-		char_en <= '0';
+		spalte_up := '0';
+
+		case state is
+			when IDLE =>
+				null;
+			when FETCH =>
+				get_next <= '1';
+				tx_data_i_next <= d_char;
+			when FORWARD =>
+				new_i_next <= '1';
+				if (tx_done_i = '1') then
+					spalte_up := '1';
+				end if;
+
+			when DONE =>
+				null;
+		end case;
 
 		if spalte_up = '1' then
 			if spalte = hspalte_max  then
@@ -111,22 +118,6 @@ begin
 			end if;
 		end if;
 
-		case state is
-			when IDLE =>
-				null;
-			when FETCH =>
-				get_next <= '1';
-				char_en <= '1';
-			when FORWARD =>
-				tx_data_i_next <= char;
-				new_i_next <= '1';
-				if (tx_done_i = '1') then
-					spalte_up_next <= '1';
-				end if;
-
-			when DONE =>
-				null;
-		end case;
 	end process output_pc;
 
 	next_state_pc : process (state, rx_new, rx_data, btn_a, d_done, tx_done_i, s_done)
-- 
2.25.1