Atom CPLD: Made C/L noise filters configurable

Change-Id: I92f6346f74dc1647fc2507df1f0b212399b359ef

vhdl_atom/RGBtoHDMI.vhdl

@@ -61,7 +61,7 @@ architecture Behavorial of RGBtoHDMI is
     constant atom_clamp_end   : unsigned(8 downto 0) := to_unsigned(512 - 255 + 248, 9);
 
     -- Sampling points
-    constant INIT_SAMPLING_POINTS : std_logic_vector(3 downto 0) := "0000";
+    constant INIT_SAMPLING_POINTS : std_logic_vector(5 downto 0) := "110000";
 
     signal shift_R : std_logic_vector(1 downto 0);
     signal shift_G : std_logic_vector(1 downto 0);
@@ -81,10 +81,12 @@ architecture Behavorial of RGBtoHDMI is
     signal counter  : unsigned(8 downto 0);
 
     -- Sample point register;
-    signal sp_reg   : std_logic_vector(3 downto 0) := INIT_SAMPLING_POINTS;
+    signal sp_reg   : std_logic_vector(5 downto 0) := INIT_SAMPLING_POINTS;
 
     -- Break out of sp_reg
     signal offset   : unsigned (3 downto 0);
+    signal filter_C : std_logic;
+    signal filter_L : std_logic;
 
     -- Sample pixel on next clock; pipelined to reduce the number of product terms
     signal sample_C : std_logic;
@@ -132,6 +134,8 @@ architecture Behavorial of RGBtoHDMI is
 begin
 
     offset <= unsigned(sp_reg(3 downto 0));
+    filter_C <= sp_reg(4);
+    filter_L <= sp_reg(5);
 
     -- Shift the bits in LSB first
     process(sp_clk)
@@ -199,15 +203,27 @@ begin
             LH3 <= LH2;
 
             if sample_C = '1' then
-                AL <= (AL1 AND AL2) OR (AL1 AND AL3) OR (AL2 AND AL3);
-                AH <= (AH1 AND AH2) OR (AH1 AND AH3) OR (AH2 AND AH3);
-                BL <= (BL1 AND BL2) OR (BL1 AND BL3) OR (BL2 AND BL3);
-                BH <= (BH1 AND BH2) OR (BH1 AND BH3) OR (BH2 AND BH3);
+                if filter_C = '1' then
+                    AL <= (AL1 AND AL2) OR (AL1 AND AL3) OR (AL2 AND AL3);
+                    AH <= (AH1 AND AH2) OR (AH1 AND AH3) OR (AH2 AND AH3);
+                    BL <= (BL1 AND BL2) OR (BL1 AND BL3) OR (BL2 AND BL3);
+                    BH <= (BH1 AND BH2) OR (BH1 AND BH3) OR (BH2 AND BH3);
+                else
+                    AL <= AL2;
+                    AH <= AH2;
+                    BL <= BL2;
+                    BH <= BH2;
+                end if;
             end if;
 
             if sample_L = '1' then
-                LL <= (LL1 AND LL2) OR (LL1 AND LL3) OR (LL2 AND LL3);
-                LH <= (LH1 AND LH2) OR (LH1 AND LH3) OR (LH2 AND LH3);
+                if filter_L = '1' then
+                    LL <= (LL1 AND LL2) OR (LL1 AND LL3) OR (LL2 AND LL3);
+                    LH <= (LH1 AND LH2) OR (LH1 AND LH3) OR (LH2 AND LH3);
+                else
+                    LL <= LL2;
+                    LH <= LH2;
+                end if;
             end if;
 
             -- YUV to RGB

vhdl_atom/fitting.notes

@@ -107,3 +107,14 @@ FB3          18/18*      28/54       63/90       8/ 9
 FB4          18/18*      29/54       39/90       7/ 7*
              -----       -----       -----      -----
              69/72      109/216     175/360     28/34
+
+10. Atom CPLD: Made C/L noise filters configurable
+
+Function    Mcells      FB Inps     Pterms      IO
+Block       Used/Tot    Used/Tot    Used/Tot    Used/Tot
+FB1          18/18*      29/54       49/90       8/ 9
+FB2          17/18       26/54       29/90       5/ 9
+FB3          18/18*      28/54       63/90       8/ 9
+FB4          18/18*      31/54       44/90       7/ 7*
+             -----       -----       -----      -----
+             71/72      114/216     185/360     28/34