diff options
Diffstat (limited to 'vidproc.vhd')
| -rw-r--r-- | vidproc.vhd | 55 |
1 files changed, 51 insertions, 4 deletions
diff --git a/vidproc.vhd b/vidproc.vhd index 485cd15..0825081 100644 --- a/vidproc.vhd +++ b/vidproc.vhd @@ -65,6 +65,13 @@ signal delayed_disen : std_logic; signal clken_pixel : std_logic;
signal clken_counter : unsigned(3 downto 0);
+-- Cursor generation - can span up to 32 pixels
+-- Segments 0 and 1 are 8 pixels wide
+-- Segment 2 is 16 pixels wide
+signal cursor_invert : std_logic;
+signal cursor_active : std_logic;
+signal cursor_counter : unsigned(4 downto 0);
+
begin
-- Synchronous register access, enabled on every clock
process(CLOCK,nRESET)
@@ -145,6 +152,38 @@ begin end if;
end process;
+ -- Cursor generation
+ cursor_invert <= cursor_active and
+ ((r0_cursor0 and not (cursor_counter(4) or cursor_counter(3))) or
+ (r0_cursor1 and cursor_counter(3) and not cursor_counter(4)) or
+ (r0_cursor2 and cursor_counter(4)));
+ process(CLOCK,nRESET)
+ begin
+ if nRESET = '0' then
+ cursor_active <= '0';
+ cursor_counter <= (others => '0');
+ elsif rising_edge(CLOCK) and CLKEN = '1' then
+ if CURSOR = '1' or cursor_active = '1' then
+ -- Latch cursor
+ cursor_active <= '1';
+
+ -- Reset on counter wrap
+ if cursor_counter = "11111" then
+ cursor_active <= '0';
+ end if;
+
+ -- Increment counter
+ if cursor_active = '0' then
+ -- Reset
+ cursor_counter <= (others => '0');
+ else
+ -- Increment
+ cursor_counter <= cursor_counter + 1;
+ end if;
+ end if;
+ end if;
+ end process;
+
-- Pixel generation
-- The new shift register contents are loaded during
-- cycle 0 (and 8) but will not be read here until the next cycle.
@@ -179,10 +218,18 @@ begin blue_val := (dot_val(3) and r0_flash) xor not dot_val(2);
-- To output
- -- FIXME: Cursor and INVERT option, teletext
- R <= red_val and delayed_disen;
- G <= green_val and delayed_disen;
- B <= blue_val and delayed_disen;
+ -- FIXME: INVERT option
+ if r0_teletext = '0' then
+ -- Cursor can extend outside the bounds of the screen, so
+ -- it is not affected by DISEN
+ R <= (red_val and delayed_disen) xor cursor_invert;
+ G <= (green_val and delayed_disen) xor cursor_invert;
+ B <= (blue_val and delayed_disen) xor cursor_invert;
+ else
+ R <= R_IN;
+ G <= G_IN;
+ B <= B_IN;
+ end if;
-- Display enable signal delayed by one clock
delayed_disen <= DISEN;
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